A few days before Christmas in 1925, Austrian physicist Erwin Schrödinger went on a two-and-a-half-week holiday to a villa on Lake Arosa in Switzerland. He left his wife Anny in Zurich, taking with him his work, his Viennese girlfriend, whose identity remains unknown, and two pearls to stick in his ears like plugs. At the age of 38, he put the girl to bed for scientific inspiration, stuck the pearls in his ears so as not to be disturbed by the noise, and set about working out the equation of waves.
He might not have thought about it if one day Nobel laureate Peter Debye had not said to him, “Schrödinger, you are not doing anything important at the moment. Why don’t you tell us something about that thesis of de Broglie that has been attracting attention for some time?” Erwin obliged him and gave a lecture on the fact that matter also has the characteristics of a wave. Debye called his contribution childish. “If you want to deal seriously with waves, you have to have an equation for a wave,” he told him.
It awakened just enough curiosity in Schrödinger to go on holiday. When he returned to Zurich on 9 January 1926, he not only had a mysterious lover with him, but also an idea about wave theory. During his next lecture, he boasted: “My dear colleague Debye said I needed an equation for a wave. Well, I’ve found it!”
Although Debye could not later recall ever challenging Schrödinger, the Swiss physicist Felix Bolch was convinced that he just did not want to remember. He regretted that he had given Schrödinger the opportunity to make the discovery that won him the Nobel Prize in Physics in 1933, instead of playing with the formula himself.
A few weeks after the formula was born, Schrödinger presented it to his colleagues. It was immediately accepted as “a mathematical tool of unimaginable power in dealing with problems of the structure of matter”, as his biographer put it. The first published peer-reviewed paper was followed by three more. He wrote and published all four in just 6 months, an unprecedented feat in the history of science. In those same 6 months, he changed the face of physics from the age of 38, when he was already considered an old man among theoretical physicists.
The historian of science Max Jammer described his 1926 publications as “undoubtedly one of the most influential contributions to the history of science…” The father of the atomic bomb, J. Robert Oppenheimer, called his theory “perhaps one of the most complete, the most accurate and the most graceful ever discovered by man”, and the great physicist and mathematician Arnold Sommerfeld described the wave equation as “the most astonishing of all the astonishing discoveries of the twentieth century”. By 1960, more than 100,000 scientific papers had been published based on his theory.
The physical interpretation of the Schrödinger wave equation and its complexity still boggles the mind today. Quantum mechanics is, in the words of Vladimir Horowitz, like Mozart’s music, “too easy for beginners and too difficult for experts”. If one has only a superficial knowledge of quantum mechanics, it is easy to do the calculations, just as a beginner can easily play the notes of Mozart, but to actually understand the calculations or to master Mozart is much more difficult.
Erwin Schrödinger understood quantum mechanics. His equation earned him the Nobel Prize, but it also earned him the eternal resentment of his colleague Werner Heisenberg. He had destroyed his work, and on top of that, he was 38 years old, came from a certain unremarkable Zurich and did not belong to the respectable quantum circles. Heisenberg could have forgiven him for all this, but he could not forgive him for being right. He and Pauli and other prominent physicists quickly retaliated with a series of scathing criticisms, but he had to eat his words later.
Before he became famous for his equation, Schrödinger was more or less a loner. He has remained so. He worked alone, and had no particular love for the branch of physics he had solved. He was like a lone rider who rode into town, saw a problem, solved it and then literally rode away.
Teacher, do you believe this?
Physics was far from his only interest. In this he was like his father, a chemist by training. Rudolf had inherited his parents’ lucrative Viennese linoleum and waxed linen business. As duty dictated, he took it over and managed it excellently, but he despised his work. He was a scientist at heart. Throughout his life, he took a near-professional interest in botany, chemistry and Italian painting, and thus became the best guide through the childhood of his only son, born to him in marriage to Georgia, 10 years his junior.
Georgia was 19 years old when they married on 12 August 1887. She looked so girlish that passers-by wondered whether she was his wife or his daughter. She was not educated as a woman of her time, but she was a very good violinist, although her expressiveness was more important than her mastery of technique. She did not pass on her love of music to her son. She gave up the violin as soon as her husband showed no interest in it.
Thus, Erwin was one of the few physicists in the future who not only did not play any instrument, but even had an aversion to music, perhaps only giving in to a love song. This probably stemmed from his father’s attitude towards his mother, but Erwin had to find another outlet for relaxation, which was usually music.
He didn’t need it in his childhood. He was the pet of his mother, aunts and housekeepers, who immediately recognised in him an exceptional child, even though his father remained his role model throughout. “To my growing son, he was a friend, a teacher and an indispensable interlocutor, a supreme authority on everything that could interest me. My mother was very good and cheerful, sickly, helpless in the face of life’s challenges, but unpretentious. I think it is to her unconditional care for me that I have to thank my respect for women today”, he later wrote.
Respect for women was something he understood in his own way, just as he had understood in his own way what it meant to be a good child in his childhood. He was defiant from a young age and outbursts were not uncommon. He was constantly arguing with his father and had to leave the table at some point because he was being nasty or rude to those around him.
He fought with his friends like all his peers, suffered boyhood injuries, of which his fearlessness made him slightly more prone, and succumbed to illnesses, one of which nearly killed him.
None of this stopped him from studying with a local teacher, which was so successful that he entered junior high school at the age of nine or ten without taking the entrance exams, after spending a summer with his grandmother in England. At school he had only three lessons a week in mathematics and physics, but he studied Goethe and Schiller in depth.
He retained his love of poetry, literature and drama even later in life, writing that he had a good time at school. He loved mathematics and physics, but also the logic of ancient languages, and hated dates and dates that had to be memorised. In German literature, he particularly liked drama, but hated the ‘pedantic dissection of their works’.
Very visually impaired, he was always first at school. His classmates thought he never learned, but at home he often sat at his books in his two rooms, although he grasped the material so quickly that the teacher could call him to the blackboard right after he had explained something and he knew the right answer. Once, even he did not.
“Which is the capital of Montenegro?” asked the teacher. He blushed and visibly suffered in front of the blackboard for his unexpected ignorance. It was the first time he had not known something and he was in complete distress. He should have said Podgorica, but he didn’t remember, and he remembered quite well what his private teacher had told him about Lutheranism. Every time he finished explaining, little Erwin would ask him, “Teacher, do you really believe that?”
They were never religious at home, and only went to church for funerals, memorials and other special occasions when their friends expected them to do so. Erwin was also baptised at home, and in his grandfather’s house, not his father’s. He was not religious in later life either. He was only interested in the history of the Christian Church, but intimately he was more attracted to mysticism.
So he spent his mornings at school and his afternoons improving his English until he spoke as well as if he lived in England. At the same time, he began to learn French of his own accord. He translated French texts into German during his philosophy lessons, during which he was bored to death by the generalised lectures. Later, he added Spanish to English and French and lectured fluently in all three languages.
High school was not only a time of learning, but also of falling in love for the first time. Lotte was the sister of his best friend Tonio Rella, with whose family he spent a lot of time, although it was also a time when he went to the theatre a lot, immersed himself in Gustav Klimt’s erotic paintings and absorbed how Klimt tried to capture the “feeling of femininity” in his images.
Later in life, Erwin was constantly trying to penetrate the essence of female sensuality. He tried to capture it by experiencing sensuality with and through women. He never tried to dominate them or be their master, but he tried to merge with them.
But when it came time to go to university, his reputation as a womaniser did not accompany him; he only acquired it later, and it was his reputation as a genius that first entered through the doors of the building. All the students immediately knew who he was. He was special, but they loved him. He was not unapproachable or haughty. If they had problems with mathematics or physics, which he himself understood almost instinctively, he could easily explain to them what the professors did not know.
“When he was working, we saw in him a real fiery spirit, almost as if he was working his way through each research to something original,” Hans Thirring, his friend who soon became as close to him as a brother, described what it was like to watch him when he warmed up to something.
But it wasn’t just physics that attracted him. He would engage in deep philosophical conversations with his best friend, the botany student Franz Frimmel, during endless evening walks in Vienna. He also gave himself over to his thoughts when he went to the mountains, although he never felt the urge to climb on snow and ice. Like most of his classmates, he was a good skier and an excellent swimmer, which he had to become if he was to survive the many childhood accidents in which he fell into lakes and rivers.
Meteorology, which he had at college, didn’t interest him much, but it may have saved his life. During the First World War, he was conscripted and sent to the Italian front as an artilleryman. When they realised that he knew meteorology, he was transferred to the Military Meteorological Service in Vienna, where he waited safely until the end of the war.
Stolen love
Before that, he fell in love again in Vienna, where the cultural scene had already begun to lose its former splendour before the war. For Ella Kolbe’s sake, he told Lotte, his high-school sweetheart, that her mother’s hopes of marriage would never be realised, and soon he too had to bury his dreams.
He fell in love with 17-year-old Felice Krauss and she fell in love with him at the age of 25. Her mother said no. At a time when a girl had almost no chance of following her heart, she stipulated that they should only see each other once a month. The ban, of course, only added fuel to the fire of unfulfilled love. The lovers missed each other a little at first and then more and more, until they were so deeply in love that they wanted to marry. They committed themselves to a future together with an informal engagement.
The only problem was that Erwin was penniless. Inflation had long since made his home business no longer as successful as it once was, and he, with his physics profession, was facing a future as a low-paid assistant. In love, he went home and asked his father if he could give up his studies and take over the home business to earn enough for himself and his wife.
My father said no. He knew what awaited his son if he sacrificed a scientific career for a business one. He experienced it himself when he took over the company he inherited, and he regretted it for the rest of his life. He would not allow his son to repeat his mistake, or he would not have been able to offer Felice what her family expected of her, even with the proceeds of the business.
Felice was the daughter of Baroness Krauss and she found Erwin completely unacceptable. He was penniless and he was an atheist. She pressured her daughter until she fell. In mid-1913 she broke off her informal engagement and the dream of love was over.
Erwin has been in love before, but he has never been ready to commit himself emotionally, spiritually and physically. Now he was. The loss of Felice cut him deeply. From then on, he had a distaste for the upper classes, and he also looked down on marriage. He later married, but he had created an emotional life for himself completely outside the rigid framework of social expectations.
After the engagement broke up, it was many years before he fell in love again with a woman who was his equal or even his superior. He did not want to risk being rejected by another family as Krauss had been, his biographers assume. So he ended up marrying the much younger Anny Bertel, treating her as an excellent housekeeper. He would never have had the same attitude towards Felice, and might actually have lived with her in marriage in the way he was used to in the house.
But he didn’t live with her. He lived with Anny, about whom he wrote honestly: “I love Anny as a friend, but sexually I have an aversion to her.” So there were always other women around him, whose names he wrote down in “little black books” and added codes to them, reporting the outcome of which relationship. Three of his many mistresses also bore him three illegitimate daughters.
Felice married the baron of her mother’s choice in 1917 and later gave birth to a daughter. She followed Erwin’s career throughout her life. For his 70th birthday, she sent him a long poem she had written for him. In one of the stanzas she reflected on how she felt as if their youth had only just passed, and their playfulness and happiness were only a moment away.
Family life for three
In fact, many years passed during which Erwin became famous for his wave equation. Not long after, he agreed to coach 14-year-old twins Withi and Ithi Jugner, who had been kicked out of school for not understanding physics. The more times he was in their company, the more he liked Ithi. When she was 17, he finally won her over. He assured her that she would not get pregnant. Of course she did, but at that moment he was no longer interested in her. She had an abortion, which went so badly wrong that she was left sterile.
In 1929, he visited his assistant Arthur March. He married in July of the same year. On his return to Berlin, Erwin gave his wife a vivid description of how much he had been charmed by Hilde March’s beauty and charm. She was not educated either, but she liked skiing, loved amateur theatre and, like him, was rather optimistic.
It was not a love that exploded in an instant. As Hilde had just got married, the feelings smouldered somewhere beneath the surface until she became one of Erwin Schrödinger’s greatest loves. She gave birth to a daughter, whom his assistant took as his own, and Erwin’s wife took as hers. Since Erwin did not want to share his bed with her, Arthur invited her into his.
When Hilde became pregnant, both couples were childless: Hilde and Arthur after four years of marriage, Anny and Erwin after thirteen. So it is possible that the child was planned, and the golden one because not long afterwards Hilde moved into his home and lived there as his “second wife”.
He also explained that he lives with two wives and that they would both look after the child when he was offered a place at Princeton. He reportedly asked whether they would be comfortable with such a family arrangement and whether it might even be illegal in New Jersey. The conservative dean of Princeton reportedly told him that he was not comfortable with this perception of the family.
It is not entirely certain whether the story is true or not, but it is very likely that Erwin had no interest in life across the pond. Until then, he had worked in his native Vienna, Zurich and Berlin, so he had no desire to go to “an old-fashioned ceremonial village full of cringing demigods on stilts”, as Einstein put it. Another reason for refusing Princeton’s offer could be that he was offered a lower salary than Einstein, and he wanted the same.
At one point he worked and lived in Oxford. At that time, Anny found a small flat in London so that he had more time for Hilde and his friends, including Hansi Bauer Bohm. It was at this time that she came to London with her husband from Berlin. Erwin had been attracted to her before, although since he had been prevented from marrying Felice, he had only been around women who were his inferiors, and she was at least culturally superior. She was not superior. She did not overlook his extraordinary intellect and boyish charm.
They had to become lovers. When Hilde left Oxford in 1935, they went on holiday together. This time, Erwin, 48 years old, was captivated by the woman, both intellectually and emotionally. Their relationship lasted until the Nazis got in the way.
Not that Erwin was a Nazi. When in 1933 they started to put Jewish colleagues abroad in safe houses, he wanted to leave too, even though he was not Jewish. “I want out”, he told Pauli, even though he was very careful in his public statements and tried to be as correct as possible at the University of Berlin. He even received an official letter signed by Adolf Hitler thanking him for his services, but he was nevertheless considered “politically unreliable” by the Nazis and was out of favour from the start.
So he moved to Oxford, but from there he went to Graz shortly before Germany annexed Austria in 1938. Hansi was Jewish and he didn’t want any trouble. He asked her to burn all his letters. She complied. One by one she threw them into the fire, feeling that, despite everything, he too was not completely immune to the virus of anti-Semitism. But he was only afraid for his job, while he was trying to get back to Oxford for at least one semester.
Happiness in Dublin
Until then, his career has followed the usual course of German scientists. In 1918, he was looking forward to a part-time professorship because it would allow him to devote himself to philosophy, his second love. At the University of Czernowitz, his dream would become a reality. “I was ready to give a good lecture on theoretical physics … but otherwise I would devote myself entirely to philosophy.” But after the First World War, Czernowitz was no longer part of Austria. “My guardian angel intervened … I had to stay with theoretical physics, and to my great amazement, sometimes something even came out of it.”
So he spent a short time at the University of Jena, and a little time in Stuttgart and Wroclaw, before spending six years at the University of Zurich, where Einstein had preceded him. This was also the most active period of his life, because it was then that he completed his major work in quantum mechanics.
When Max Planck retired in Berlin in 1927, Planck persuaded him to succeed him. Now, for the first time, life was really fun: Berlin was a centre of theoretical and experimental research and he shared his days with Planck, Einstein and Max von Laue.
He and Einstein became good friends. Neither of them liked the pretensions or the ossifications of their colleagues. Erwin often visited Einstein at his summer house on Lake Schwiel in Potsdam. They would walk around for hours or go sailing together. Erwin loved sailing so much that he bought his own boat.
Anny and Erwin worked well as a couple at the time, but only outwardly. They threw parties, the house was full of friends and everything was relaxed, but when the friends were gone, there was no happiness in the house either.
But Anny got used to everything. For example, that she drives the car. Erwin liked to slip into meditation while driving, which was not very safe. Her attitude to the law was as special as her husband’s. “For her he was a great husband in every way, a man above criticism and above ground. She was willing to tolerate his deceptions and be his safety net when he wanted her,” his biographers wrote.
And so, when he fled Germany because of the Nazis, she went with him to Oxford, from there to Graz, back to Oxford, from there to Ghent and on to Rome. There Erwin was approached by the Irish Prime Minister, Eamon de Valera, who was also a mathematician and a scientist. He suggested that he spend the war at the Institute of Advanced Studies in Dublin. There was little money for research, but he would head the School of Theoretical Physics.
Erwin accepted the offer. He surprisingly liked life in Ireland and worked with enthusiasm again. The students loved him. Not only because he was a good lecturer, but also because of his knowledge of Irish music, Celtic design and the Gaelic language.
In Ireland, he had only one problem: the weather didn’t suit him. He was increasingly plagued by respiratory problems, but in 1956, after 16 years of living in Dublin, he returned to Vienna because of them, but also because of homesickness.
At that time, he was also known as a molecular physicist. In 1944, he published a booklet called What is Life?, in which he ventured into a world that had hitherto been alien to him. Francis Crick, who with James Watson discovered the double helix of DNA, later said that this booklet was largely responsible for his turn from physics to molecular biology.
Did he dissipate his energy by pursuing many interests and therefore achieve less in the field of physics? No. He saw integrity in everything that interested him. Thus, in the introduction to What is Life?, he talks about the different ways of thinking that are important to him, and he keeps returning to them.
He also constantly returned to the defence of humanism in science. It seemed to him that theorists were too closed in their own circles and only talked among themselves. The remedy for this, he thought, was to deal with things that did not concern their own field, even at the risk of making a fool of themselves. So, as a precaution, he also excused himself for daring to enter the field of molecular physics:
“A scientist is expected to know some things first-hand, completely and in depth, but because of this he is also expected not to write about areas in which he is not an expert. This is perceived as ‘noblesse oblige’.” He then asked to be relieved of this “noble obligation” because “we have inherited from our ancestors a longing for comprehensive knowledge, all-embracing knowledge”.
In his defence, he also reflected on whether it is better to be a generalist or an expert in one field. He concluded that some people can afford to take trips to areas where their knowledge is not perfect, even at the risk of making a fool of themselves.
Sexuality as a science
His scientific work was incredibly multifaceted. In his early years, for example, he worked on the theory of colour perception, and then became familiar with almost all aspects of modern physics: statistical mechanics, general relativity, X-ray diffraction and the like, and, of course, quantum mechanics, which was his main field.
But he also thought about sexuality in the same depth as he did about physics and philosophy. In fact, he thought about it so much that it became his most important non-scientific work. He not only enjoyed lovemaking, he consciously saw it as a path to transcendence and the possibility of being freed from oblivion.
According to him, human sexual behaviour was largely unlearned and instinctive: “All these hard-to-describe, partly painful, partly divine feelings, and above all the spontaneous decision to fall in love, point to special memory traces in man which are not peculiar to all species.” Thus he rationalised the fact that he was capable of falling in love with any attractive young woman who came into his vicinity.
But serial falling in love was not his only characteristic. In his everyday life, he was also constantly involved in arguments. He was very irritable and could burst out like a child. It was at this stage that he usually wrote his philosophical writings.
As in love, he was fascinated by beauty in science. He wrote to Max Born: “I want nothing more than to reveal the beauty of science. I put beauty before science. We are always longing for our neighbour’s wife and for perfection, which we will almost certainly never attain.”
But Erwin Schrödinger, who drove around in a BMW, was no stranger to fears. Almost neurotically, he feared that he would be stricken by poverty in his old age, or that Anny would end up in it if something happened to him.
This fear probably stemmed from the years of inflation between the wars, when his family slipped from being fairly well-off to the brink of poverty, but it certainly also brought back memories of the years when he lived on the money Anny earned as a secretary, because his university salary was almost non-existent.
The pension has almost become a fetish. He was so obsessed with it that he could hardly see the present, even though he had safely stashed the Nobel Prize money in a Swiss bank. He was one of those who had always done well and yet constantly feared poverty.
Quite unnecessarily. He lectured at the University of Vienna as long as his health allowed. After he discovered the wave equation, although he did not produce anything of significance, he left behind the so-called Schrödinger’s cat mental paradox as revenge. He used it to illustrate the incompleteness of the early interpretation of quantum mechanics in the transition from sub-atomic to macroscopic systems.
A cat sits in a sealed box. Connected to the box is a device containing radioactive atomic nuclei and a container of poison gas. The cat cannot interact with the device. The test is ready when there is exactly a 50% chance that the nucleus will disintegrate within one hour. If the nucleus disintegrates, it will emit a particle that triggers the device, which opens the canister so that the gas kills the cat. If the core does not disintegrate, the cat survives.
Quantum-mechanically, the unobserved particle is a superposition (co-existence) of a “decayed” and a “non-decayed nucleus”. When the observer opens the container, he sees only the “decayed core or dead cat” and the “non-decayed core or living cat” respectively. So the question is: when does a system cease to exist as a mixture of both states and become one or the other?
