Schrodinger

Schrodinger was born in Austria in 1887 and was educated in Vienna.

He was at the University of Zurich in 1926 where he published his great breakthrough with his wave mechanics. He then went to Berlin to take up the Chair previously held by Max Planck.

With the rise of the Nazis he left Germany and took up a Fellowship at Magdalen College, Oxford in 1933.

He returned to Austria in 1936 but soon had to leave after the Anschluss in 1938.

After short periods back in Oxford and then Belgium, he eventually was appointed to a position at the new Institute for Advanced Studies in Dublin.

He stayed there until 1956 when he moved back to Vienna. He died in 1961.

— David C Clary (2022) "Schrodinger in Oxford" Singapore : World Scientific - page xi

Biography

Early Life in Vienna

Erwin Rudolf Josef Alexander Schrodinger was born on August 12, 1887 in Vienna. Erwin was an only child. His family had a large apartment in central Vienna with a view of St. Stephen's Cathedral. The Austro-Hungarian Empire was at its peak and Vienna was the centerpiece. Science, music and the arts were all flourishing with great names such as Boltzmann, Freud, Mahler and Klimt producing their best work.

His father, Rudolf, would have preferred a career in science as a botanist, but he instead took over the family business as the owner of a small factory. His maternal grandmother was born in England. His aunt, Minnie, helped bring Erwin up and he spoke English with her from an early age. Minnie was married to Max Bamberger, who was a Professor of General Chemistry at the Vienna Polytechnic -- which later became eventually the Technical University of Vienna --. His mother took him to visit members of their family back in Leamington Spa in England. Thus, even as a child, Erwin was exposed to science and to the English way of living. Erwin started his studies at the Akademisches Gymnasium in Vienna in 1898. This was the oldest secondary school in Vienna with an emphasis on Latin, Greek and German Literature. He graduated from the Gymnasium top of his class and entered the University of Vienna in 1906. Through the work of physicists such as Doppler, Stefan and, most notably, Boltzmann, the University had gained an outstanding reputation for teaching and research in physics in the second half of the 19th century.

Schrodinger attended the lectures in practical physics given by the Director of the Physical Chemistry Institute Franz Exner. In Exner's department, important work had been done on synthesizing radium chloride, which was sent to Rutherford in the UK who used the material for discoveries on the structure of the atom. Exner had also been involved in providing uranium compounds used by Marie and Pierre Curie for their work on radioactivity. Schrodinger performed an experimental project under the supervision of Exner on the conduction of electricity on the surfaces of insulators in moist air. He spoke on this work at a meeting of the Academy of Sciences in Vienna in 1910. His thesis enabled him to be granted the degree of Dr.phil, which nowadays is equivalent to a Master's Degree.

Austria-Hungary at that time had a scheme in which young men who had gone through a significant education could volunteer for military training of one year. This enabled them to avoid the three years of compulsory military service. Therefore, in 1910 Schrodinger volunteered for service in the fortress artillery. Over Christmas, Schrodinger went on a ski trip with his friend Hans Thirring, who broke his leg and had to leave the military service. This enabled Thirring to take up a vacant assistant post with Hasenohrl. Thus, when Schrodinger passed his military training a year later as a cadet officer and returned to the University, he could not work with Hasenohrl and continued experimental research with Professor Exner and his assitant Fritz Kohlrausch. However, he concluded that he was not ideally suited for experimental work. By this time, the great experiments in physics were being done in other countries such as France, the UK and Germany. So he turned to doing individual theoretical work on problems of interest to experiment.

The next qualification in his academic career was the Habilitation, which would enable him to give his own lecture courses, for which he was paid. To achieve this, he had to publish his own papers and give a public lecture on his research. He developed a theory for diamagnetism, in which the electric currents associated with the motion of electrons produce an internal magnetic field. But this theory, based on the velocity distribution of the Scottish scientist Maxwell, did not give good agreement with experiment.

Later, there was a great scientific congress in Vienna to which many of the leading scientists of the day were invited to lecture. As he had achieved his Habilitation, Schrodinger was allowed to attend, but did not give a presentation. This was the first time he had seen Albert Einstein, who spoke on his latest ideas on gravitation. This sparked a new interest for Schrodinger, who just a few years later started an intense correspondence with Einstein that lasted throughout their careers.

World War I

The assassination of the Archduke Franz Ferdinand on 28 June 1914 in Sarajevo set in motion the fast sequence of events that led to the First World War. With Vienna as the epicentre of the Austro-Hungarian Empire, mobilization occured at once. Being aged 26 and a reserve in the army, Schrodinger was called up at once as an artillery officer. He was sent to the border with Italy. At that time Italy was still neutral in the war. Schrodinger was highly fortunate as many of his former student colleagues were sent to the great battles of the Russian front, where the Austro-Hungarian army suffered badly.

With is theoretical style of pursuing research, he was still able, during this period, to continue to think about scientific problems without the need for laboratories or libraries. He even managed to complete some scientific papers. One was on the capillary pressure of gas bubbles and another was on the Brownian motion of particles, the theory of which had been pioneered by Einstein.

Italy finally entered the war in May 1915 on the opposing side to Austria. Schrodinger was moved to Gorz near Trieste. Here there was fierce fighting with the losses on both sides in the hundreds of thousands. However, as he was commander of an artillery battery, he did not see very dangerous service himself. His efforts must have been useful as he received a military citation and was promoted to Oberleutnant, the highest lieutenant officer rank. It was around this time that his former teacher Professor Hasenohrl lost his life in an infantry charge in Tyrol.

Later, Schrodinger was then moved back to Vienna to teach a course for anti-aircraft officers. His experience as an artillery officer inspired him to write a paper on the audibility of large explosions. He developed his own classical wave equation for this problem, which would sow the seed for his great work on another wave equation.

Around this time, Schrodinger also published his first paper on quantum theory. Schrodinger wrote a detailed review of the theory of specific heats, to which Planck, Einstein, Debye and Born had all contributed. Schrodinger's review on specific heats was published in the new journal Naturwissenschaften, which covered all the sciences. It was edited by Arnold Berliner and was a German equivalent to the British journal Nature. In due course Schrodinger became a close friend of Berliner, submitted several more papers to his journal and they corresponded frequently.

Schrodinger studied Einstein's general theory of relativity when he was at the Italian front in 1916. This allowed him to write two short papers on the topic on his return to Vienna in 1917.

Schrodinger was building a reputation for himself. He was approached in 1918 by the Franz Joseph University of Czernowitz about an appointment there. Czernowitz was a small city which had been ruled by several different nations and had been occupied by Austria since 1775. However, in the chaos at the war, the city was taken over first by Ukraine and then Romania. This made it impossible for Schrodinger to take up an appointment there.

In the last year of the First World War, the Austro-Hungarian Empire fell apart. Life became very difficult in Vienna. There was runaway inflation. Food became scarce. When the war finished in November 1918, Schrodinger's military pay was stopped. His income from the University was hardly sufficient to support himself. Schrodinger had continued to live in the apartment of his parents, while his father's business had collapsed. This was the first time in his life that Schrodinger had experienced real hardship. Then, in 1919 his father died.

Moving to German

At the University of Vienna, replacements for Hasenohrl to the Chair of Theoretical Physics and Exner to the Chair of Experimental Physics were to be made in 1920. The appointments of Gustav Jager and Felix Ehrenhaft, respectively, were disappointing to Schrodinger. But, around this time, he was offered an assistantship with Max Wien at Jena in Germany. The financial situation in Germany was better than Austria and the salary offered was quite attractive. So, even though the position in Jena was not a permanent one, Schrodinger took the major step in April 1920 of moving away from Vienna for the first time.

Just before his move to Jena, Schrodinger married Annemarie "Anny" Bertel. She was aged 23 and Schrodinger 32. Anny was the daughter of a photographer in Salzburg. Schrodinger had known her since she was a teenager.

Despite the severe financial and political problems in the early 1920s, theoretical physicists had become much in demand in German universities, following the great advances in quantum theory & relativity and many positions were opening up. Almost as soon as the newly-wed couple arrived in Jena in April 1920, Schrodinger was offered a permanent a associate professorship at the Hoschschule fur Technik in Stuttgart and he moved there in October.

At this time, Schrodinger's mother had become very ill in Vienna with cancer. The value of his late father's investments and pension had been much reduced by inflation and she had been turned out of their comfortable apartment. This had a major influence on Schrodinger. It did much to make him neurotic about financial security. He was always tempted by an apparently lucrative offer to a new position. So, just six months later, Schrodinger was on the move again to a more senior professorship in Breslau.

Moving to Switzerland

He was then approached by yet another university, and this time it was major appointment. Einstein, Max von Laue and Peter Debye had all held professorships at the University of Zurich. The officials there were looking to make a new appointment to continue this great tradition in theoretical physics. Schrodinger received a strong reference from his recent colleague Regener who had been impressed by the clarity of Schrodinger's lectures, even though he had moved on from Stuttgart all too quickly. In addition, the faculty at Zurich had noted the breath of his papers, covering many different areas of physics.

Switzerland had avoided the horrors of the First World War. There was no hyperinflation. The salary and pension offered were more attractive than those Schrodinger had been receiving at the German universities. At the relatively young age for a full professor, Zurich was an ideal appointment. Even though he was well aware he had not yet made a research contribution at the very top level. This was Schrodinger's opportunity to settle down and produce his great work.

As soon as he started at the University of Zurich in October 1921, Schrodinger became ill with a serious bout of bronchitis. Five appointments in five different cities in two and a half years were taking their toll. Tuberculosis was suspected and he needed to move to a high altitude to recuperate. The Schrodingers went to Arosa, a town in the Swiss Alps.

In Arosa, Schrodinger wrote two papers that continued his progress with quantum theory. The first was on the quantization of vibrations to calculate the specific heats of solids at high temperatures. The second was on the quantized Bohr orbits of an electron. He mentioned the possible need for the use of complex number in the description of the Bohr orbits.

After nine months, Schrodinger was feeling well enough to return to Zurich. As a full professor at the University of Zurich, Schrodinger had to give an inaugural lecture. He chose the title "What is a Natural Law?" In this lecture, he emphasised the statistical nature of matter.

4th Solvay Conference

His rising reputation allowed Schrodinger to be invited to his first Solvay Conference on Physics in 1924. These conferences, supported by the King of Belgium, had become the leading international gathering for the discussion of the very latest developments in physics. The subject was "The electrical conductivity of metals and related topics". Schrodinger did not present a paper. The photograph for this 4th Solvay Conference shows Marie Curie, Ernest Rutherford, Paul Langevin and William H. Bragg in the front row with Schrodinger somewhat nervously appearing in the third row. It would not be very long before Schrodinger would be moved to the first row and indeed his wave mechanics eventually provided a rigorous theory for explaining electrical conductivity.

It should be noted that scientists based in Germany and Austria were not invited to this Solvay meeting due to the tensions still prevailing after the First World War. So there was no Planck, Einstein, Sommerfeld or Born. However, as Schrodinger was based in Switzerland, he did receive an invitation and there was space for him due to the other abstentees.

Schrodinger Equation

Since his convalescence, he often visited Arosa because Schrodinger was inspired by the mountains where he could concentrate without interruption of his work. It was the place where he discovered his equation. This great breakthrough of the Schrodinger equation occured over Christmas 1925 in Arosa. The first communication of Schrodinger on the discovery of his equation seems to be a handwritten letter sent from the Villa Herwig, Arosa to Wilhelm Wien in Munich on 27 December 1925.

"Just now a new atomic theory is niggling me. If only I knew more mathematics! I am very optimistic about this thing and hope that if only I can master the calculations, it will be very fine."

The paper, the first with the Schrodinger equation, rates amongst the greatest publications in the history of science. The new work very soon received acclaim from the most distinguished theoretical physicists.

Max Planck on 2 April 1926 wrote from Berlin :

"I read your article the way an inquisitive child listens in suspense to the solution of a puzzle that he has been bothered about for a long time. I am delighted with the beauties which are evident to the eye."

Einstein wrote on 16 April 1926 to Schrodinger :

"Professor Planck pointed your theory out to me with well-justified enthusiasm. Then, I studied it too with the greatest of interest. The idea of your article shows real genius."

Following his first paper on wave mechanics, and encouraged by the acclaim he had received, Schrodinger went on to publish one new paper on his equation in nearly every month in 1926 until the summer. This was the most intense period for research in his life. In his final paper in the series, Schrodinger proposed a version of his equation in which his wave function depends on time. This paper was his final burst of genius and Schrodinger did not again publish an original paper at this very top level.

Later, he worked very energetically to promote his new theory to audiences around the world. In the summer of 1926, he lectured in his old universities of Jena and Stuttgart, and also in Munich and Berlin. The reception to his lecture from the senior scientists in Berlin, including Planck, Einstein, Nernst and von Laue was very favourable. Planck even invited him to a reception in his house.

Schrodinger also received an invitation from Danish scientist Niels Bohr, who had won the Nobel Prize four years before. Bohr met Schrodinger at Copenhagen railway station in October 1296 and could not leave the lecturer alone for several days in intense discussion of the new theory. The strain was too much for him and he took to his bed in Bohr's house. It was the tradition in those days for the host to invite a distinguished speaker to stay at their own house. Bohr could not resist coming to Schrodinger's bedside to continue the discussion.

Schrodinger was aware of the emerging importance of scientific research in the USA. He arranged for the translation of his collected papers on wave mechanics into English. This is a language which Schrodinger spoke perfectly because of his family links. At the end of 1926, he also published a paper in the "Physical Review", an American journal which was fast evolving as a leading journal for all areas of physics. These publications were a break from essentially all of Schrodinger's previous articles which had been published in German journals and in German language.

Just before Christmas in 1926, almost exactly one year after he discovered his equation, Schrodinger and Anny set sail in a French liner to visit the USA for the first time. He kept a rather amusing diary of the trip. The Atlantic crossing took ten days.

The Schrodingers spent several weeks in Madison at the University of Wisconsin, then travelled by train to the California Institute of Technology (Caltech), Pasadena, stopping off at the Grand Canyon on the way. After Pasadena, he took the train via Salt Lake City and over the Rocky Mountains to Denver, on to Chicago and then to MIT and Harvard. Everyone wanted to meet him and he was a celebrity. At one time, he had to give three talks in a 30-hour period. He gave 57 lectures during this three month visit. His trip forward and backward in many cities across the USA had some similarities to the extensive tours given today by modern rock stars.

His final lecture was at Columbia University in New York before taking the boat for the long cruise home.

Berlin

The Friedrich Wilhelm University was the oldest university in Berlin. Max Planck had held the Chair of Theoretical Physics since 1889. He had won the Nobel Prize in 1918 for his discovery of energy quanta and was to retire in 1926. Max von Laue also held a Chair there, and he had won the Nobel Prize for his work on the diffraction of X-rays by crystals. In addition, Albert Einstein had a non teaching professorship being the Director of the Kaiser Wilhelm Institute for Physics in Berlin. He had moved from the ETH Zurich in 1914.

Several person were considered for the Planck's Chair. Sommerfeld had been the most prolific at supervising early career theoretical physicists who had gone on to major academic careers and this made him first choice. However, he did not want to leave Munich. Debye's interests were thought to be more on the experimental side. Heisenberg, although clearly recognized as a genius, was considered to be too young for a major Chair at the age of just 25.

The appointments committee noted Schrodinger's ingenious invention of wave mechanics, his superb lecturing style and his "charming temperament of a South German". He was also very highly rated by Planck who had been so impressed by his first paper on wave mechanics.

Meanwhile, the University of Zurich came back with a counter offer to attempt to retain their star physicst. Anny recalled

The offer in Berlin was very high from the first moment on. So Zurich tried to get a bit more, but it never came the salary which Berlin offered. When it came to the end, they offered him a double-professor at the ETH and at the university, so that both could pay, but even then he wouldn't have had much as he got in Berlin.

The students in Zurich heard about the offer and organised a torchlight processing that ended in front of Schrodinger's house. He and Anny found this very touching.

Schrodinger and Anny moved to Berlin in August 1927. They rented a large apartment at 44 Cunostrasse in Grunewald.

5th Solvay Conference

Not long after his move to Berlin came the 5th Solvay Conference in Brussels. The topic was "Electrons and Photons". Schrodinger was asked to give one of the main lectures. The Conference did much to promote Schrodinger's breakthrough. However, Schrodinger was still not considered senior enough to be placed in the front row of the photograph for the Conference.

Essentially all of those names who had contributed to the recent development of the quantum theory were at this Solvay Conference, including Bohr, Born, de Broglie, Dirac, Heisenberg, Pauli and Schrodinger. As many as 17 of the attendees had won the Nobel Prize or were to be awarded the Prize. The anti-German prejudice that had prevented Einstein and others from attending the Solvay conferences held after the First World War had melted away. The meeting was chaired by Lorentz who Schrodinger had recently met in Pasadena, where Lorentz had mentioned to him that he would be invited to give a lecture at the 5th Solvay Conference. Lorentz died a few months later.

This meeting is often considered the most celebrated of all the Solvay Conferences. The meeting's chair, Lorentz, invited Schrödinger to give a lecture regarding his newly discovered Schrödinger equation. Schrödinger talk at that meeting was entitled "Wave Mechanics". He started off by summarizing the main conclusions from his papers published in 1926. The statistical interpretation of Schrödinger's wave function was a major discussion point. Both Einstein and Bohr were highly prominent in the debate.

Experimental evidence for the new quantum theory was also a topic at the conference. The experiments of Clinton Davission and Lester Germer, in which electrons scattered from the surface of nickel showed a diffraction pattern, and those of Arthur Compton, in which the frequencies of X-rays were changed when scattered by free electrons, supported de Broglie's ideas on wave-particle duality. Of these three American scientists, Compton had been able to make the long boat trip over the Atlantic for the meeting.

There were several comments from the participant of the meeting. Born wrote to the organiser to say it was the most stimulating conference he had ever taken part in. Heisenberg said :

"Through the possibility of exchange between the representatives of different lines of research, this conference has contributed extraordinarily to the clarification of the physical foundations of the quantum theory. It forms, so to speak, the outward completion of the quantum theory."

Paul Dirac from Cambridge was the youngest person to attend this Solvay Meeting at the age of 25. His view of the meeting was

"I listened to the arguments, but I did not join in them, essentially because I was not very much interested. It seemed to me that the foundation of the work of a mathematical physicist is to get the correct equation. That the interpretation of these equations was only of secondary importance."

On returning to Berlin, Schrodinger was thrown into a major course of lectures covering several areas of physics but with emphasis on electron theory. He was an eloquent and popular lecturer. At that time in Berlin, there was a remarkable range of lectures that the fortunate students could attend. Planck was still lecturing, Lise Meitner gave a course on nuclear physics, Nernst on experimental physics, Ladenburg on spectroscopy, Fritz London on chemical bonding.

Lectures in London

Sir William Henry Bragg had won the Nobel Prize in 1915 with his son William Lawrence Bragg for his work on the diffraction of X-rays by crystals. He had attended the 5th Solvay Conference where he had heard several of the pioneers of the new quantum mechanics speak. He was now the Director of the Royal Institution, in the centre of London.

The Royal Institution had become famous not only through the pioneering experimental research of Humphry Davy and Michael Faraday, but also through the communication of science from lectures to the public. This tradition has continued in great style to the present day. The Royal Institution is based in Albemarle Street at a walkable distance from Buckingham Palace and Downing Street. Members of the Royal family often attended the discourses given on Friday evenings.

Bragg invited Schrodinger to give a course of lectures. Schrodinger was pleased to accept it as it would, for the first time, enable him to speak on wave mechanics to a distinguished English audience. Bragg himself gave a lecture at the Royal Institution in advance of Schrodinger's arrival as a prologue to the talks on wave mechanics and emphasized the wave-particle duality of electrons.

Schrodinger gave four lectures in London on 5,7,12 and 14 March 1928 with the title "Wave Mechanics". Anny accompanied him. Schrodinger did not lecture at a Friday evening discourse. His lectures were too technical for the general public, so they were presented on Mondays and Wednesdays.

Between two of his lectures at the Royal Institution, Schrodinger visited Cambridge. He gave a lecture at the Kapitsa Club in Trinity College on Saturday, 10 March, on "The Physical Meaning of Quantum Mechanics". The Russian physicist Pyotr Kapitsa had started this club to hear the latest developments in physics in an informal setting with blackboard and chalk.

Schrodinger had caught a cold during his visit to Cambridge. He was confined to bed in the house of George Birtwistle. There, Schrodinger was visited by the physicist George P. Thomson who had some exciting new experimental results on electron diffraction. Thomson's results demonstrated experimentally the wave nature of the electron and so were of particular interest to Schrodinger. George Thompson was the son of the great Cambridge physicsist J. J. Thomson, who was awarded for the Nobel Prize for Physics in 1906 for his discovery of the electron.

Schrodinger finished his trip to England by visiting Dr. Frederick Pidduck at Corpus Christi College, Oxford on 15 March. This was his first visit to Oxford after the publication of his 1926 papers.

After his visits to London, Cambridge and Oxford, Schrodinger and Anny made their way to Leiden in the Netherlands. There, Paul Ehrenfest, who had taken the Chair of Lorentz, held a lecture series to rival the Kapitsa Club in Cambridge. After a good dinner, Ehrenfest would fire probing questions at the visiting speaker who would be staying in the guest room of his house at 57 Witte Rozenstraat. The speaker would then write their signature on the wall in the hall just outside the guest room. Many of the great theoretical physicists had signed in this way, including Einstein, Planck, Bohr and Dirac. Schrodinger added his signature on 21 March 1928.

World War II

After the severe financial problems following the First World War, the situation had gradually improved there through the 1920s but this all changed in October 1929 when the Wall Street stock market crashed. There were very serious economic ramifications around the world and this included Germany. Unemployment rose fast and there were riots on the streets of Berlin. The political situation was becoming complicated with Soviet Russia continuing to expand its influence. Right-wing movements becoming more popular throughout Europe. Hitler and his party of National Socialists took full advantage of this situation and he eventually became Chancellor of Germany on 30 January 1933. Meanwhile, in the run up to this momentous event, Schrodinger had beeen working to communicate his breakthrough in quantum mechanics to the world and had not had any time to be concerned with the politics.

Einstein himelf was Jewish and had already given up German citizenship long time ago when he moved to Switzerland in 1895 at the age of 16. Einstein was travelling back to Germany by boat after visiting the California Institute of Technology when he heard in March 1933 that his apartment in Berlin had been raided several times by the Nazis as had his summer house in Caputh. He was advised by friends that it was dangerous to return to Germany. He arrived in Antwerp and sought the assistance from the King of Belgium, whom he had got to know at the Solvay Conferences. Einstein renounced his German citizenship and resigned from the Prussian Academy of Sciences. In the summer of 1933, Einstein secretly moved to a small house in the coastal town of Cromer in Norfolk, England where he had armed guards.

Einstein was Schrodinger's close friend. Back then, Schrodinger and Einstein often went sailing together and Schrodinger stayed at Einstein's vacation house in Caputh. Schrodinger had been particularly concerned by the treatment of his close friend Einstein who was the first to be forced overseas. They kept up a close correspondence after Einstein was forced to leave Germany, As Einstein had, out of necessity, moved abroad, Schrodinger was now very seriously thinking of doing the same.

Later, Einstein had a major influence on the British attempts to assist the many refugee scientists who left Germany in the 1930s.

Moving to Britain

Shortly after the Nazis came to power, the Academic Assistance Council was set up in Britain by several notable people, including Lord Rutherford. This Council over the next few years helped over 2,600 academic refugees to come to Britain. As many as 16 later won Nobel Prizes, 74 became Fellows of the Royal Society, and 34 Fellows of the British Academy. Furthermore, after being rescued by Britain, several of these scientific refugees moved on to the USA.

Frederick Lindemann, a regular attender at the Solvay Conferences, was a supporter of the Academic Assistance Council. He was well aware of the lead that Germany had taken in physics, so he went to Germany in 1933 to see if he could encourage some of the most promising but demoralised physicists to come to Oxford. Lindemann arrived in Berlin on Easter 1933. He went to see his old research supervisor Nernst. There he met Professor Franz Simon. Simon had worked previously with Nernst and was nor leading a group doing research on low temperature physics. Lindemann realised that here was an opportuiny to build up a new research effort in low temperature physics at Oxford with Simon leading the team. ICI had major interests in the properties of gases and Lindemann anticipated he could persuade them to support the work of this team led by Francis Simon. He then made the arrangements for them to move to Oxford.

Lindemann did not stop with Simon's team. He had heard about the work of Fritz London, who had nominally been Schrodinger's assistant. As a Jewish Privatdozent working in Berlin in 1993, London's prospect's were bleak. Although he was not a theoretician, Lindemann realised the important role theoretical physics had played in driving forward new development in physics in Germany. Meanwhile, Lindemann also appreciated London's more pratical approach to theory. He anticipated London could work on low temperature problems with Simon's experimental group.

Lindemann was invited to meet with Schrodinger in his apartment at the 44 Cunostrasse. Schrodinger explained he was very unhappy about what was happening in Germany. Lindemann mentioned he had made an offer to Fritz London to come to Oxford. Schrodinger then enquired if London had accepted it or not. Lindemann said that London was still considering the offer. Schrodinger said that he didn't understand why London had not accepted the offer but if London didn't want to go to Oxford then Schrodinger himself was interested. Lindemann was taken aback and asked Schrodinger if he was serious and he said he was. Having spent vacations in England as a child and speaking perfect English, Schrodinger felt comfortable with this move.

Schrodinger was not a "non-Aryan". He was not going to be dismissed from his Professorship in Berlin. However, he was well aware by now that several of his colleagues were looking for post overseas. In due course, the scientists such as Bethe, Bloch, Born, Debye, Delbruck, Einstein, Franck, Frisch, Haber, Heitler, Hess, Infeld, London, Mark, Meitner, Peierls, Polanyi, Simon, Stern, Szilard, Teller, Weisskopf, Weyl and Wigner all became refugees.

Lindemann realised that someone of Schrodinger's standing would need the prestige of a Fellowhsip at one of the Oxford colleges. Lindemann's own college, Christ Church, had already provided a Visiting Fellowship for Einstein, which had had its complications. So, he approached Professor George Gordon, the President of Magdalen College, Oxford.

Oxford

The University of Oxford is the oldest English-speaking university in the world.In 1993, there were 24 colleges associated with the University. Many of the colleges were founded originally by bishops or royalty. The colleges are self-governing and some have considerable endowments. They control their own membership and have their own internal governance structures, buildings and grounds. Each college elects its own head who chairs the Governing Body of Fellows, which agrees on the main decisions of the college.

Oxford was traditionally very strong in the arts and humanities, and particularly in subjects such as classics, ancient history and theology. Some great scientists such as Robert Hooke, Robert Boyle and Cristopher Wren had attended the University of Oxford. They were early Fellows of the Royal Society which was founded in 1660. By 1933, only two Oxford scientists had won the Nobel Prize. These were Frederick Soddy, who won the Chemistry Prize for his work on isotopes and Charles Sherrington, who won for his discoveries on the nervous system. By contrast, the University of Cambridge had won 14 Nobel Prizes by this time. Some of these were great discoveries such as electron by J.J. Thomson and the structure of the atom by Rutherford. Meanwhile, research in Physics at Oxford was in the doldrums in 1933. There was no Professor of Theoretical Physics and the limited research in this area was largely conducted in colleges by mathematicians. Lindemann was well aware of this dire situation and this is why he went to Germany with the aim of recruiting top physiscist to Oxford.

Magdalen College, Oxford was founded in 1458 by William Waynflete, the Bishop of Winchester. He provided a significant endowment for the College and built some fine buildings set in beautiful grounds. In the early 1930s Magdalen College did not have a very strong reputation in Physics. But through its Sherardian Chair of Botany and Waynflete Professorships of Physiology, Chemistry, and Mathematics, it had played a leading role in Oxford. In 1933, Sir Charles Sherrington was the Waynflete Professor of Physiology. He had initiated a dramatic improvement in the reputation of Medical Sciences in Oxford. Two of his research students at Magdalen, Howard Florey and John Eccles, went on to win the Nobel Prize for themselves. Robert Robinson, the Waynflete Professor of Chemistry, went on to win the Nobel Prize for Chemistry in 1947 for his research on the synthesis of organic molecules of biological importance such as penicillin and morphine. Magdalen College has also been home to the Sherardian Chair of Botany since 1734. Arthur Tansley, the holder of Sherardian Chair of Botany from 1927-37, was a pioneer in the science of ecology. He, through detailed studies including Wicken Fen near Cambridge, coined the term ecosystem.

Lindemann finally met with Schrodinger in September at Lake Garda. He communicated the positive details of the letter from George Gordon arranging a Fellowship at Magdalen College with every prospect of tenure together with a research grant. He was also able to give more details of the financial support from ICI. There were no formal duties apart from research on which a report would need to be written for ICI every year and it would be necessary to live in Oxford.

On the 9th of November 1933, Schrodinger came to Magdalen College in Oxford. He was admitted as a Fellow of the College by the President George Gordon, using Latin phrases requesting Schrodinger to obey the Statutes and Bylaws of the College. Schrodinger replied "Do Fidem", which is translated as "I swear." He then shook the right hands of all the Fellows present and each one said to him, "I wish you joy." The ancient bells then rang from the Magdalen Great Tower. Schrodinger and his new colleagues processed to the High Table in the Hall to celebrate his admission over a fine dinner.

At the end of the dinner, President Gordon was called to his office in the President's Lodgings to receive a telephone call. It was from the Times newspaper saying that the Royal Swedish Academy of Sciences had just announced that Schrodinger had won the Nobel Prize in Physics for 1933, jointly with Paul Dirac from the University of Cambridge. President Gordon then called Schrodinger to his office to inform him of the happy news. Gordon said to Schrodinger, "I think you may believe it as the Times would not say such a thing unless they really know. As for me I was truly astonished as I thought you had won the prize."

In this way, Schrodinger won the Nobel Prize as a Fellow of Magdalen for just a few hours.

Nobel Prize

Ever since the creation of these prizes in Physics, Chemistry, Physiology - Medicine, Literature and Peace by Alfred Nobel in his will of 1896, they have captured the imagination of the scientific community and the public around the world. In Physics, the Nobel Prize is given to the person who made "the most important discovery or invention" in the field. Being awarded by the Royal Swedish Academy of Sciences and presented in a lavish ceremony by the King of Sweden, the Nobel Prizes have a special independence and kudos. Indeed, once a scientist has won the Nobel Prize, it puts them above other scientists in the public eye. Schrodinger would have been well aware that many of the physicists he had interacted with had already won the Nobel Prize in Physics. This includes Lorentz, the Braggs and Curies, Lenard, Thomson, Wien, von Laue, Planck, Stark, Einstein, Bohr, Millikan, Franck, Hertz, Compton, Richardson, de Broglie and Raman. However, at that time, ther had been no prize awarded for the new quantum mechanics.

In the preliminaries, the Chair of the award committee writes to previous prize winners asking for their opinon on who is most deserving of the award. In addition, they write to other notable scientists such as presidents of academies, or heads of major departments in the subject of the award. The committee always looks to see who wrote the very first papers that led to a "most important discovery or invention", in the words of Nobel.

In a letter to the Committee of 25 September 1928, Einstein had already mentioned Schrodinger as deserving of the Prize, although he considered de Broglie to have precedence. Later, De Broglie was actually awarded the Prize in 1929. Then once again, Einstein mentioned Schrodinger in his letter to Nobel Committe dated 30 September 1931 :

I nominate the founder of wave or quantum mechanics : E. Schrodinger of Berlin and W. Heisenberg of Leipzig. In my opinion, this theory contains without doubt a piece of the ultimate truth. The achievements of both men are independent of each other and so significant that it would not be appropriate to divide a Nobel Prize between them.

However, the Nobel Committee was hesitating as a new discovery or invention arising from the theory was needed under the strict interpretation of Nobel's will. While wave mechanics could explain the spectrum of the hydrogen atom, Heisenberg had actually used his theory to predict in 1927 that the ortho form of the hydrogen molecule (with parallel nuclear spins) would be three times more abundant than the para form (with opposite nuclear spins). This was experimentally verified in 1929 by Harteck and Bonhoeffer. It provided clear evidence of a new discovery arising from a quantum mechanical prediction. Furthermore, Niels Bohr had placed Heisenberg first preference, with Schrodinger second.

Meanwhile, by 1933, many predictions of the specra for diatomic molecules had been made by Mulliken, Hund, Lennard-Jones and others using a molecular orbital theory based on Schrodinger's wave mechanics. Several of these predictions had been verified experimentally. Therefore, the Nobel Committe was anticipating giving the prize for 1932, retrospectively, to Heisenberg, and that for 1933 to Schrodinger.

However, a startling development was made in an observation using a cloud chamber by Carl Anderson a Caltech of the positron. This new particle had been predicted previously by Paul Dirac with his own relativistic form of quantum mechanics. Dirac had only three nominations for the Nobel Prize, although one was from the influential William H. Bragg. That was enough.

As Heisenberg's first paper (1925) had preceded Schrodinger's, the Nobel Committee decided to give the 1932 Prize to Heisenberg while splitting the prize for 1933 equally between Schrodinger and Dirac. During the selection process in 1932, the Nobel Committee for Physics decided that none of the year’s nominations met the criteria as outlined in the will of Alfred Nobel. According to the Nobel Foundation's statutes, the Nobel Prize can in such a case be reserved until the following year. Therefore, both the 1932 and 1933 prizes were announced that year.

The Nobel Awards Committee for Physics made its final recommendation on 23 September 1933. Rumours on the decision then started to spread. The recommendation from the committee needed to be approved at the meeting of the Royal Swedish Academy of Sciences before any official announcement could be made. Finally, on 9 November 1933, the Royal Swedish Academy of Sciences had met and decided formally to award the 1932 Nobel Prize in Physics to Werner Heisenberg "for the creation of quantum mechanics, the application of which has, inter alia, led to the discovery of the allotropic forms of hydrogen" and the 1933 Prize jointly to Erwin Schrodinger and Paul Dirac for "the discovery of new productive forms of atomic theory".

Since the announcement, there was only one month before the presentation of the award in Stockholm. Therefore, much urgent preparation was needed. This included buying clothes, preparing lectures and booking tickets. Meanwhile on November 18 did the promised confirmatory letter from Henning Pleijel, the Permanent Secretary of the Royal Swedish Academy of Science arrive. He stated :

I have herewith the honour to confirm my telegram by informing you that the Royal Swedish Academy of Science in its meeting of November 9th has decided on this year's Nobel Prize for Physics being awarded to you together with Professor Paul Dirac as a reward for the discovery of new fertile forms of the atomic theory.

On behalf of the Academy I also have the honour to invite you to the solemnity to be held at Stockholm on the anniversary of the decease of Alfred Nobel (10th of December), where the amount of the prize as well as the diploma and the medal in gold will be handed over to you. Immediately after the festival a banquet will follow at Grand Hotel Royal in this town.

If on your presumptive visit to Sweden you should be accompanied by a friend or by members of your family, they of course are also included in that invitation. In this case you would oblige me very much by informing me kindly of their names in order that cards may be duly issued to them.

I also would be very much obliged to you if you would let me know, as soon as possible, whether you intend to give, on this occasion, the lecture which is incumbent on each Prize winner within six months of the Founder's day at which the prize was won, and what your wishes may be with regard to that lecture which has to treat the subject to which the prize has been awarded.

Finally, as I presume that you will arrive in Stockholm some day before the 10th and that it could be of some interest to you to become acquainted, before the festival, with some of the leading persons in our Academy, Mrs Pleijel and I would feel really honoured if you would partake together with some scientists of this town in a quiet dinner at our home in the Academy at the 9th of December (Saturday evening).

Schrodinger received strict instructions for his visit to Stockholm from the Nobel Foundation who were organising the celebrations. For a report that would be published, he was asked to send a high-quality photograph of himself and a short biographical note of 1-2 pages containing the most important dates in his life, a summary of his most important work and especially that for which the Nobel Prize was awarded. He was also asked to send a copy of the short speech he was to give at the Nobel banquet, the Nobel lecture, and any associated photograph.

The invitation from the Royal Swedish Academy included the possibility of bringing family members to the celebratitons. Anny Schrodinger joined her husband. Dirac was not married at that time so his mother was his guest. Heisenberg also brought his mother. All the Laurates arrived with their female guests at Stockholm central station on the morning of 9 December. There were many cameramen and a photograph was taken here. They were taken to the Royal Grand Hotel for breakfast. Then, they were given a tour of Stockholm. In the evening they attended the dinner hosted by Professor Pleijel, the permanent secretary of the Royal Swedish Academy of Science. A total of 32 Nobel laureates and ladies were present. The dinner went on until 12 am.

The 10th of December was the big day for the presentation of the Prizes on the anniversary of the death of Alfred Nobel. In the morning the Laureate parties were taken to the Swedish Museum. In the afternoon they were taken on a procession through the crowded streets to the grand ballroom of Stockholm Concert Hall. The Nobel Laureates were to be seated on the plafrom opposite King Gustaf V in the front row.

At 5pm the trumpets played and the Laureates, each escorted by a host, were taken to their velveted seats on the platform. It was a smaller set of Laureates than normal as Thomas Hunt Morgan from Caltech, who had won the Prize for Physiology or Medicine for explaining the role of the chromosome in heredity, was unable to attend and there was no Prize for Chemistry that year. The Chairman of the Nobel Foundation Dag Hammarskjold then gave a welcoming speech. Then there was a speech of reminiscences on Alfred Nobel by Ragnar Sohlman, the creator of the Nobel Foundation, who had been the executor of Nobel's will.

The Laureates were called in turn with Heisenberg first, followed by Schrodinger and then Dirac. Before the presentation of the Nobel Prizes by the King, Henning Pleijel gave a summary of the work of each Laureate that had led to the Nobel Prize. He started off by summarising the research of previous Nobel Prize winners on whose discoveries the new development in quantum mechanics were based. This included Planck, Einstein, Rutherford, Bohr and de Broglie. He then summarised the work of Heisenberg, who was presented with his Nobel Prize by the King. After this, it was Schrodinger's turn. Pleijei said :

For your discovery of new fruitful forms of atomic physics and the application of these, the Royal Academy of Sciences has decided to award you the Nobel Prize. I request you to receive this from the hands of His Majesty the King.

Schrodinger then bowed to the King who presented him with a heavy blue and gold leather case. This contained the 23-carat gold Nobel Prize medal struck by the Swedish Mint. On one side, the medal portrayed the face of Alfred Nobel and his birth and death dates in Latin numerals. The reverse had engraved the name E. Schrodinger, the year 1933, and an inscription from the Aeneid : "Inventas vitam iuvat exclouisse per artes" which translated is "It is beneficial to have improved life through discoveret arts". The case for the medal contained a cheque made out to E. Schrodinger for 85,000 Swedish Kroner. The King also presented a unique certificate designed by the Swedish artist Elsa Ortengren.

After the final award for Literature was made to Ivan Bunin, the Swedish National Anthem was played. The Laurates and their guests were then taken to the Nobel Banquet held back at the Grand Hotel where they were staying. After the dinner, the Nobel Prize winners were invited to give a short speech. Dirac gave a speech on how physics theories could be applied to economics. It is always a risk when scientists move outside their expert field and the reactions from those present were somewhat puzzled. Meanwhile, Heisenberg just give a simple vote of thanks.

The next day Schrodinger gave his Nobel Lecture. The title was "The Fundamental Idea of Wave Mechanics". He chose to discuss wave-matter duality. It was mainly an exposition of the ideas of de Broglie interpreted by Schrodinger. Heisenberg in his Nobel Lecture on "The Development of Quantum Mechanics" gave a balanced description of the improvements of the simple quantum theory that led to quantum mechanics. Starting off with Planck, describing his own work, and then those of Schrodinger and Dirac. He finished by mentioning Gamow's proposal that the forces in the nucleus are different to those in the electron shell of an atom. The whole new area of nuclear and elementary particle quantum physics was just starting.

Dirac's Nobel Lecture was more mathematical on "The Theory of Electrons and Positrons". He also gave one of the first tantalising proposal on anti-matter :

If we accept the view of complete symmetry between positive and negative electric charge so far as concerns the fundamental laws of Nature, we must regard it rather as an accident that the Earth -- and presumably the whole solar system -- contains a preponderance of negative electrons and positive protons. It is quite possible that for some of the stars it is the other way about, being built up mainly of positrons and negative protons. In fact, there may be half the stars of each kind. The two kinds of stars would both show exactly the same spectra and there would no way of distinguishing them by present astronomical methods.

Schrodinger deposited his 85,000 Swedish Kroner Nobel Prize cheque in a Swedish bank account. This meant that when he later had to leave Austria in a hurry in September 1938, the Nazis were unable to confiscate his prize money, which they did with other Nobel Prize winners who were forced to leave Austria.

Schrodinger's Cat

While in Oxford, Schrodinger published four papers which have been very influential. These papers extended the debate on the appropriate interpretation of quantum mechanics.

The first of these papers was submitted to the Mathematical Proceedings of the Cambridge Philosophical Society on 14 August 1935. It was communicated by Max Born. "Communicated" refers to the process by which a scientific paper is submitted to a journal for publication by a third party, who is typically an established member of the academic community. Born acted as a mediator between the author of the paper and the journal. He would have reviewed the paper and deemed it appropriate for publication in the journal, and then submitted it on behalf of the author. In those days, to ensure the integrity of a paper submitted to a journal of a learned society, it needed to be communicated by a member of the society.

The paper, written in English, had the title "Discussion of Probability Relations between Separated Systems". It stated :

When two systems, of which we know the states by their respective representatives, enter into temporary physical interaction due to known forces between them, and when after the time of mutual influence the systems separate again, they can no longer be described in the same way as before, viz, by endowing each of them with a representative of its own.

I would not call that "one", but rather "the" characteristic trait of quantum mechanics. The one that enforces its entire departure from classical lines of thought.

By the interaction, the two representatives (or ψ-functions) have become entangled. To disentangle them we must gather further information by experiment.

This problem had become quite well known in quantum chemistry. When two electronic wave functions (orbitals) based on different atoms in a molecule which are placed quite far apart can still be mixed together if there is an interaction between them. The mixing becomes strongers if the two original states have similar energies, even if they are quite far apart in distance.

This paper has become highly cited in modern times as it is an early work discussing some of the principles behind quantum information processing and quantum computation. It also introduced the word "entangled" into quantum mechanics. The problem expressed in the final sentence above, with regards to disentangling the states in a practical experiment, remains one of the key challenges in quantum computation.

The paper referenced one published by Einstein, Podolsky and Rosen, in which it was argued that quantum mechancis provides an incomplete description of physical reality. That paper had considered two interacting particles. If the position of the first particle was measured, under the principles of quantum mechanics, the result of measuring the position of the second particle could be predicted. However, they claimed this was unsatisfactory as no action taken on the first particle could instantaneously influence the other particle, as information would then be transmitted faster than light.

Scrodinger then followed up his first paper on entanglement with a second one to the same journal entitled "Probability relations between separated systems". In this case, the paper was communicated to the Cambridge Philosophical Society by Paul Dirac. This paper develops the concept of mixtures of states that had been introduced by John von Neumann. The paper concludes by stating on mixed states that : "These conclusions, unavoidable within the present theory but repugnant to some physiscists including the author, are caused by applying non-relativistic quantum mechanics beyond its legitimate range".

The third paper from Schrodinger in Oxford was published on 29 November 1935 in Die Naturwissenschaften, the popular science journal whose editor had been Schrodinger's close friend, Arnold Berliner. In the paper, Schrodinger stated :

A cat is penned in a steel chamber, along with a tiny bit of radioactive substance in a Geiger counter, which must be secured against direct interference by the cat. The radioactive substance is so small that perhaps in the course of the hour one of the atoms decay, but also, with equal probability, perhaps none of the atoms decay. If it decays, the counter tube discharges. Then, through a relay, it releases a hammer which shatters a small flask of hydrocyanic acid.

If one has left this entire system to itself for an hour, one would say that the cat still lives, if meanwhile no atom has decayed.

The ψ-function of the entire system would express this by having in it the living and (pardon the expression) dead cat mixed or smeared out in equal parts.

Because Schrodinger used the example of the life or death of a cat, it has caught the imagination of the public more than any other of his works to the present day. Accordingly, "Schrodinger's Cat states" is also a phrase used by physicists in connection with a microscopic quantum effect having an influence on a macroscopic phenomenon.

Back to Austria

Schrodinger visited Austria in 1935 to give his guest lectures in Vienna. He also visited Graz where his old friend Kohlrausch was based. The possibility of a post there was discussed further. After returning to Oxford, he wrote to Hans Thirring on 1936:

In the last four weeks (and more) I have let the Austrian affair go through my head and I regretted that after the visit to Graz and the second conversation in the Ministry I could no longer talk to you in a frank manner.

The following dream has now developed for me. Couldn't you get people around to turn the professorship in Graz into something that plays between Graz and Vienna? I don't want to officially accept a full teaching commitment in Graz, but would like to do a small amount also in Vienna.

I would like to go back. I felt so warm and at home in Austria during the weeks I was there.

By the spring of 1936, Schrodinger was having detailed negotiations with the federal authorities about a position back in Austria. And finally by the summer of 1936, Schrodinger had settled the arrangements for a Chair at the University of Graz and an Honorary Professorship at the University of Vienna.

Anschluss

Schrodinger had been working away from Austria for 16 years when he returned in 1936. His home country had seen many changes during this period.

When he left Vienna to go to Jena in Germany with his new bride Anny in 1920, the Austro-Hungarian Empire had collapsed just two years before. A provisional assembly had drafted a constitution. Over 98% of the population in the border regions of the Tyrol and Salzburg were in favour of unification of Austria with Germany. But the Treaties of Versailles and Saint-Germain, signed by the victorious allies in 1919, forbade this Anschluss unification. Nevertheless, the first constitutions of the Weimer Repulic and the First Austrian Republic expressed a political goal for unification.

In the 1920s, Austria and Germany both suffered severe economic problem which was exacerbated by the worldwide financial crash at the end of the decade. There were many political parties and changes of government. The ties of the more powerful Germany with Austria remained strong, particularly with the need for minerals and skilled labour. Hitler was born in Austria and his National Socialist Party had the firm aim of reuniting all Germans who lived in the countries neighbouring Germany. He had written in Mein Kampf that he wished to create a union between Austria and Germany.

The Christian Socialist Party, the dominant party in Austria in the late 1920s, did not favour an Anschluss or association with the Nazis. After Hitler was made Chancellor of Germany in 1933, there was considerable unrest in Austria from the Nazi groups there. There was civil war in 1934 and all political parties, except the Christian Socialist, were banned. Engelbert Dollfuss, the Cancellor of Austria, was assassinated by Austrian Nazis in an attempted coup in 1934. He was replaced by Kurt Schuschnigg, who was anti-Hitler.

By the summer of 1936, it seemed obvious to many observers that the political situation in Austria was rapidly deteriorating but Schrodinger failed to realise this. It seems that his friend Hans Thirring, who largely responsible for bringing him back to Austria, was not fully aware of this either. Schrodinger wife Any commented :

It never occured to us that this step might turn out to be rather foolish, even dangerous. Many of our friends shook their heads and soon we understood their attitudes.

Two years later, on January 1938, the headquarters of the Austrian National Socialist Party in Vienna was raided by the Austrian police who discovered a huge cache of arms and plans for a putsch.

Later, on 12 February 1938, Schusnigg, the Chancellor of Austria, had met with Hitler in his residence at Berchtesgaden. Hitler proposed that Nazi sympathiser be appointed to positions in the Austrian Government. This included making Arthur Seyss-Inquart the Minister of Public Security, which could control the police. In return, Hitler said the would affirm his support for Austrian sovereignty.

Chancellor Schuschnigg called a referendum on 9 March proposing to keep Austria independent of Germany. Hitler was furious and insisted that the referendum must be cancelled. Under much pressure of an invasion, Schuschnigg agreed on the cancellation. Hitler then demanded Schuschnigg's resignation and replacement by Seyss-Inquart.

Then, on 12 March 1938, German troops entered Austria and were greeted by jubilant crowds with Nazi salutes and flags. Seyss-Inquart, now the Chancellor, signed an act making Austria a province of Germany. Hitler himself then entered Austria. He went first to his birthplace of Braunau am Inn and then on to Linz, the town of his boyhood. After this, he went to Vienna. In front of a jubilant crowd of 200,000 in the Heldenplatz, he said : "The oldest eastern province of the German province, shall be, from this point on, the newest bastion of the German Reich". Heinrich Himmler and Reinhard Heydrich entered Austria with members of the SS and arrested several prominent politicians, political dissenters and Jewish citizen. Three weeks later Hitler returned again to Austria. He visited Graz on April 4. On the same day, the New York Times reported on his visit : "This Styrian Nazi stronghold (Graz) gave Chancellor Adolf Hitler a reception today that surpassed even his triumphal entry into Vienna a fortnight ago. The hurricane of "Heils" that greeted his arrival was the final outlet of the Styrian longing for unification with Germany".

The Magdalen Fellow in Politics, William Mackenzie, was travelling in Austria just after the Anschluss. At the suggestion of President Gordon, he managed to arrange a meeting with Schrodinger and Anny. Mackenzie wrote to Lindemann on 21 April 1938 :

I was staying at the Seekarhaus in the Radstadter Tauern and took the chance of sending a postcard to Mrs. Schrodinger at Graz. I was rather surprised to get a phone call last Tuesday, the 12th, to say that they had just arrived at the nearest hotel, a couple of miles or so from the Seekarhaus. They both came up to lunch next day, the 15th, and were with me most of the afternoon. We had a very long talk about things in general.

Schrodinger himself is in good health, has not at any time been under arrest and has not been personally molested. His correspondence, however, is probably being tempered with. No letter from him is to be taken at its face value. Anything sent to him should be as colourless as possible.

The University had been shut since the disturbances in February. After the Nazis took over, several of the professors were arrested. The University reopens this week, but Schrodinger's personal position is one of complete uncertainty. He summed it up by saying that they ought logically either promote him to a better job, or put him in a concentration camp. He had no idea which it would be and he doesn't know who is responsible for deciding his fate. Nor what his attitude to the regime is supposed to be. Nor whether he is debarred completely from leaving the country. At least, for the present, he certainly cannot come to Oxford to lecture without specific authorisation from some high power. He doesn't even know whether he needs permission to travel to Berlin.

In regard to future plans, he would on the whole like to make his peace with the regime if they will let him. So that his policy is to establish a reputation as a non-political person.

We had four or five hours of talk. Naturally, there was a great deal more than this said, but I think these are the main points.

Lindemann wrote back to thank Mackenzie on 22 April 1938. He had an additional worrying query about a letter from Schrodinger published in the German papers. Lindemann was referring to a letter that had been published under Schrodinger's name on 30 March 1938. The local newspaper, the Grazer Tagespost, gave the letter the headline "Acclamation of the Fuhrer : A Leading Scientist offers himself for the Service of Nation and Fatherland". His scientific colleagues in Europe and America felt particularly let down by the statement. Some of his former colleagues and associates never forgave him. He also had to do a lot of explaining with close friends, including Einstein, Born and Dirac, when he met or corresponded with them personally in the years to come. Later, he wrote to Einstein with an explanation : "I hope you did not seriously denounce my subsequent, certainly quite cowardly, behaviour. I wanted to stay free. I couldn't do it without gross hypocrisy".

The German Consulate in Graz had also seen Schrodinger's public statement seeming to support Hitler. They had forwarded it to the Department of Foreign Affairs in Berlin. The response came that : "The question of withdrawing his Professorship might still be addressed by the local administration". Finally, Schrodinger received a leater from the dean of University of Vienna :

On the basis of the decree of the Austrian Ministry of Education of 22 April 1938, No 12474/I/1b, your authorisation to participate in instruction in the Philosophical Faculty of the University of Vienna is withdrawn. You are, therefore, to refrain from any professorial or other duties falling on you within the scope of your former appointment or especially assigned to you.

Following Schrodinger's dismissal from the University of Vienna, it would not be long before the same occured from the University of Graz. On 26 August 1938, the Ministry of Education in Vienna wrote :

On the basis of Sect 4. Paragraph 1 of the ordinance for renovation of the Austrian civil service of 31 May 1938, RGBI.I S. 607, you are dismissed. The dismissal is effective as of the day of arrival of this notice. You have no right to any legal recourse against this dimissal.

Escape from Austria

The formal description of the ordinance was "the retirement or dismissal of politically unreliable civil servants." For the first time, the alarm bells were truly ringing in the ears of Schrodinger and Anny. Anny described what happened next.

When the Nazis came to Austria, my husband got several invitations to foreign countries.

He was not allowed to get the telegrams himself. They were brought to the university. He was called to the university and he was told : "Of course, you have to refuse. You can't go to Brussels or so." So it was really absolutely like a prison.

Only through de Valera we were secured. He knew that we were in danger. But it was absolutely sure he could not write to my husband because everything was censored. So he asked Whittaker to ask born. Born wrote to our friend Professor Richard Bar in Zurich. He told a Dutchman, who then came to Vienna. He came to my mother and told her this important thing. He wrote down in just a few lines that de Valera wanted to create an Institute for Advanced Study and whether he would come, in principle. My mother sent this little piece of paper to Graz. We saw it, we read it three times, and then destroyed it, put it into the fire, and told nobody about it at all.

Later, I went with my car with Thirring as far as Munich. I went to Switzerland to Constance. I met our friends there and I told them : "Yes, in principle, he will come. But nothing should be done that will let anybody know that we are going away." My friends wrote that to Born, Born told Whittaker, Whittaker told de Valera.

My husband never spoke to de Valera. He Never knew de Valera. Nothing at all. But when this missive came, he was perfectly sure that he must leave Austria at once.

Eamon de Valera was a prominent Irish politician who had been a commander in the 1916 Dublin Easter Rising. He had been the Taoiseach (Head of Government) of Ireland since 1937. He had graduated from the Royal University of Ireland and taught mathematics at several schools. He had heard about the Institute for Advanced Study in Princeton. He was impressed by the recruitment there of Einstein and Weyl. With the distinguished refugees leaving Germany and Austria in large numbers, he had the vision of creating a similar Institute for Advanced Studies in Ireland through recruitment at the top level.

Sir Edmund Whittaker, who Schrodinger had met one year before in Rome when they were made founding members of the Pontifical Academy of Science, was a close friend and advisor to de Valera. He had discussed the idea of the Institute for Advanced Studies in detail with de Valera and was a good choice to act as a go-between from De Valera to Max Born and other quiet and careful contacts.

So in three days we packed everything. Three suitcases, we had nothing more. We left everything in Graz behind, took a return ticket to Rome, because everybody knew us in Graz. We didn't dare to take a taxi, so that they knew what we have got with us. With my car I brought the luggage to the station, and then I brought it back to the garage, and I said that they should wash the car. I never saw the car at all again of course. I never saw the other things either because they were confiscated. And with ten marks in our pocket, we left Graz.

Schrodinger had to leave all of his personal documents behind when he fled from Austria. This included his Nobel and Max Planck gold medals. They left Graz on 14 September 1938, taking the day-long train ride to Rome. At that time, it was possible to cross the border from Austria to Italy without a visa. Once the Schrodingers arrived in Rome, they headed for the Vatican, where Schrodinger had been received at the Pontifical Academy of Science.

We didn't have the money to pay the porter in Rome. There Fermi told us : "Don't write from Rome because it is already dangerous. It might be censored."

From Vatican City, where the Papal Academy is situated, my husband wrote three letters. One was to Lindemann to tell him that we left Graz. One to our friends in Zurich to get us some money, because we had to borrow money from Fermi. The third one to de Valera, who was the President of the League of Nations at that time. That was a Saturday when we posted the letters in Vatican City.

On Monday morning we went again to the Academy. After half an hour's time, came a servant who told us that his excellency was wanted at the telephone. The Irish envoy was at telephone and he said de Valera rang up this morning from Geneva. He told him to do everything for us to bring us as soon as possible into Geneva. We should be at the legation in the afternoon and there de Valera would phone.

So, we were there. This was the first time my husband heard de Valera speaking. He said that he was glad that we were out of Austria. He also said that we should come to Geneva to discuss a few things. But as soon as possible, we should go to England or Ireland, because there was such a great danger of war in 1938. The Munich Conference, you know.

The Munich conference was going to be held at the end of September 1938. It involved the leaders of Britain and France, meeting with Hitler and Mussolini. The question was the transfer of the German-speaking Sudeten part of Czechoslovakia to Germany. After much discussion, the transfer was agreed with an international commission to consider the future of other disputed areas. On his return, the British PM Chamberlain famously announced, "Peace for our time." Lord Halifax, who did not go with Chamberlain to Germany, informed the House of Lords that the agreement made was a "lesser of two evils".

Anny continued the description of their movements

So de Valera tried to get everything ready for us. We couldn't take any money out of Italy, but he gave us a pound each and gave us first class tickets and off we went. I was quite happy already. I felt already safe, but my husband didn't feel safe at all.

In Domodossola they looked at our passports and the luggage. They hardly looked at the luggage at all, but the passports were all right. Then, before we came to Iselle, a carabinieri came into our compartment. He had a piece of paper with our name written on it and we had to leave the compartment with all our luggage. They had looked at our passports. We already had visas for all of Europe because de Valera had said that if we can't go through France, we must go through Spain or Portugal or something.

Then, we were asked if we had some money. We said that we had one pound. They thought that we had to smuggle something, because one can't go through Europe on one pound.

Finally, after another 24-hour train trip, they arrived in Geneva. Schrodinger met with de Valera. Then, they stayed for three days in his hotel and then rode on.

There was a blackout in Switzerland. On the other side of the Rhine, one could see the bright lights of Germany.

Trains were overflowing and greatly delayed. In France we passed airports with countless airplanes standing ready. All bridges and tunnels were under military guard.

In England in Hyde Park, bomb shelters were being feverishly prepared. Anti-aircraft guns pointed to the sky. Everyone had gas masks. In Paddington, we heard reports about the Four Power Conference in Munich. That day, 80,000 children were evacuated.

On the 28 September 1938, we reached Oxford.

It was becoming clear that, due to his letter seemingly supporting the Fuhrer, Schrodinger was not nearly as welcome in Oxford as he had been. The Schrodingers were fortunate to be able to stay in the spacious house of J.H.C Whitehead. Whitehead and Schrodinger had run their joint seminar in Oxford some three years before and had become good friends.

Following his flight from Austria and Italy, Schrodinger had no personal resources except his Nobel money in Sweden. That was not even readily available. With just the small grant from Magdalen to live on in Oxford, the Schrodingers were living almost hand to mouth. However, de Valera remained very enthusiastic and provided funds for Schrodinger to travel to Dublin to meet him.

There, De Valera explained that it would take about a year to get the legislation passed through the Irish Parliament to set up the Institute for Advanced Studies. De Valera also had an interest in Celtic Studies. He constructed an Act to "make provision for the establishment and maintenance in Dublin of an Institute for Advanced Studies, consisting a School of Celtic Studies and a School of Theoretical Physics". The strange mix of Celtic Studies and Theoretical Physics was to produce some criticism from the opposition members in the Irish Parliament that would delay the passing of the Act.

Things were now very uncertain for Schrodinger and Anny. However, as has frequently been the case in Schrodinger's story when he was unsure about his future, he then received a very welcome letter. This was from the Fondation Francqui in Belgium offering him a Visiting Professorship at the University of Ghent. He at once accepted. As was often his method to announce the next move in his career, Schrodinger arranged for Nature on 31 December 1938 to report :

Professor Erwin Schrodinger has been appointed by the Fondation Francqui as a Visiting Professor for the next six months to a "Chaire Francqui" in the University of Ghent. His address is Laboratory of Physics, Plateaustraat 22, Gand, Belgium.

Moving to Ireland

The summer of 1939 was a very tense time for the whole of Europe. Schrodinger was waiting more and more anxiously for the call to come to Dublin. On 1 September, German troops invaded Poland and on 3 September Britain and France declared war on Germany. At that time, Belgium was remaining neutral, but it was very vulnerable and had a border with Germany. Schrodinger still had German nationality that once caused a difficulty with the authorities in Belgium. With the announcement of war, de Valera realised he had to act very quickly. He informed Schrodinger he should come to Dublin as soon as possible, even though his Institute for Advanced Studies had not yet been approved by the Irish Parliament. A temporary professorship was being arranged for him.

De Valera's promise to assist with travel permits and visas came through. Schrodinger left Belgium on 4 October 1939. First taking a ferry from Ostend to Dover. After arriving in England, the Schrodinger party then travelled to London, leaving from there at 9 pm to Liverpool, going on to Holyhead in Wales and then taking another boat at 4 am to Dublin.

Upon his arrival in Ireland, Schrodinger was being funded on a temporary basis by University College Dublin and the Royal Irish Academy. Irish politics, was volatile. De Valera could easily have lost his position of Taoiseach and his proposed Institute for Advanced Studies. Nevertheless, Schrodinger's reception in Dublin was much more enthusiastic than he had been the case in Oxford. In Dublin, he was an academic superstar who was head and shoulders above other academics in the country in terms of his international repuation.

He had developed a popular style of lecturing in almost perfect English and in general terms with no mathematics. He was invited to give many public lectures which were enthusiastically received, advertised and reported in the national Irish press. The Irish Independent on 4 November 1939 reported :

Prof. Erwin Schrodinger, Nobel Prize Winner who formerly held an academic chair in Vienna and was just dismissed from his post by the Nazis, began a course of lectures on the latest form of the Quantum Theory at University College Dublin, yesterday.

The lecturer paid a tribute to the work of the late Sir William Rowan Hamilton, Astronomer Royal and former President of the Royal Irish Academy. He had been deeply impressed by his work, he said, long before he had come to Ireland.

By 1940, the German army had invaded Belgium, the Netherlands and Denmark. Chamberlain had resigned and Winston Churchill had become Prime Minister of Great Britain. The situation was getting critical just over the Irish Sea. Meanwhile, the bill to create the Dublin Institute for Advanced Studies was finally passed by the Irish Parliament on 19 June 1940. The first appointment to be made was Professor Erwin Schrodinger as Senior Professor in the School of Physics. He was also appointed to the Council of the Institute for Advanced Studies. So finally Schrodinger had his permanent appointment in a safe place away from the war ravaging close by in Europe. The annual salary was £1,200. This allowed him to cover the living expenses for himself and his family in reasonable comfort.

After a succession of nine moves in 20 years with appointments in Jena, Stuttgart, Breslau, Zurich, Berlin, Oxford, Graz, Ghent and Dublin, he did not anticipate that he would be living in Ireland for as long as 17 years. During his 17 years in Ireland, Schrodinger was hugely popular with the public and with the press. As time moved on, he chose more and more general title for his public lectures such as "What is Life", "Science at Play", and "Fun in Science". They were sell-outs. He had become the public face of science in Ireland. Every new prize, election to an academy, new appointment or Honorary Degree, was reported in complementary terms in the "Irish Press".

De Valera himself had founded the "Irish Press" newspaper, which always reported very positively on the Taoiseach and his colleagues. Accordingly, Schrodinger was regularly asked by the Irish Press to comment on almost any subject. Even when he went on cycling holidays, it was reported in the press. It seems that any movement he made or any comment he expressed was reported. There were non-sensational reports on his life at home with his family with no difficult questions asked. After the Second World War, he was also in regular demand to speak on highly serious topics such as the nuclear bomb, or how to deal with German or Austrian Nazis.

Wave Mechanics

One-Electron Hidrogen Atom

Schrodinger was awarded the Nobel Prize for the equation under his own name which he published early in 1926 when he was working at the University of Zurich. In this paper, he wrote down a new equation for the description of the electron in the hydrogen atom. It had the simple form HΨ = EΨ. Here H contains mathematical terms representing both the kinetic energy and the potential energy of the electron. At particular quantised energies, contributions from the kinetic and potential energies cancel to leave just the constant energy E of the electron.

This equation gave a very simple form for the possible energies of the electron of the hydrogen atom in terms of integers describing the different quantum states and fundamental constants associated with the mass and charge of the electron, together with Planck's constant.

This formula for the energy states had been given first by the Danish physicst Niels Bohr, who found it fitted to the results derived by Balmer and Rydberg from the lines they observed experimentally with different colours in the emission spectrum of hydrogen gas. It was not this energy formula, however, that seemed so revolutionary to the scientists of the day, but the wave function Ψ, also denoted by Schrodinger as an "orbital". This new mathematical invention gave very accurately all the other observed properties of the electron, such as the spectrum for electron in the presence of an electric field, an observation known as the Stark effect.

The term "wave mechanics" was given by Schrodinger to his theory because it relates to the work of the French physicist Louis de Broglie who had proposed that the electron has some properties similar to those of a wave. Accordingly, shortly before his discovery, it was suggested to Schrodinger by his Zurich colleague Peter Debye that there ought to be a mathematical equation for the electron describing it as a wave. That is exactly what Schrodinger discovered.

It was easy to write down Schrodinger's equation for any number of electrons and protons, but it was harder to solve it, even in an approximate form, especially for an atom or molecule with more than one electron. However, the idea of the orbital for one electron at once found many uses in the qualitative description of chemical bonding and properties of molecules.

Two-Electron Helium Atom

Niels Bohr had not been successful at extending his own theory to atoms with more than one electron and to molecules. Schrodinger himself did make unpublished attempts to to this with his own theory, but without success. However, he was not aware of the work by Uhlenbeck and Goudsmit, which suggested that an individual electron could have different quantum states that were visualised as the particle spinning clockwise or anticlockwise. When Schrodinger's wave functions were modified to include these spins, the spectrum for the two-electron helium atom was explained, as was the chemical bonding of the hydrogen molecule. Linus Pauling stated, "His great discovery based on an idea, the idea that the properties of atoms and molecules could be calculated by solution of a differential equation."

Positron

Not long after the publication of the first paper by Schrodinger, the Cambridge theoretical physicist Paul Dirac published his own form of quantum mechanics which incorporated the treatment of Einstein's theory of relativity. He predicted a new kind of particle, which was called a positron. This particle had the same properties as an electron, except for an opposite charge. It was observed soon after its prediction.

Follow Ups

In 1926, Schrodinger followed up his paper on the energy levels of the hydrogen atom with four other papers which were published in the Annalen der Physik. He demonstrated that his equation described the harmonic oscillator and rotational motion, which can be identified with the vibrating and rotating states of a diatomic molecule. He also showed that his new quantum theory could be made equivalent to an alternative approach developed a few months before by Heisenberg, Born and Jordan. He developed his theory to show how it applied to the Stark effect. Finally, he derived a second Schrodinger equation in which his wave function depended on time.

Research Style

Schrodinger had received an education which had allowed him to move eventually to a top university in which he could undertake his own research. He had developed his own particular style of finding a problem of interest to experimentalists, proposing an equation to describe the system and finally using rigorous mathematics to find analytical solutions. He did this work completely on his own and not in a research group or even guided by a more senior scientist. Elsewhere, many of the most celebrated theoretical physicsts of the time were emerging from large research groups headed by distinguished professors.

Schrodinger did his research on his own and this enabled him to tackle unique problems in his personal style. He had a good supply of research projects from his close link to the experimental department of Exner. There is a parallel to Paul Dirac at Cambridge University who developed his quantum theory entirely on his own, but was still aware of the great experimental discoveries being made on the structure of the atom at the Cavendish Laboratory in Cambridge.

Schrodinger was no focused just on science and nothing else. He was an avid theatre goer and read very widely in philosophy.

References

• C.W Kilmister (1987) "Schrodinger : Centenary Celebration of a Polymath" Cambridge : Cambridge University Press
• David C Clary (2022) "Schrodinger in Oxford" Singapore : World Scientific