The physicist who inspired the word boson and who, together with Einstein, predicted the fifth state of matter
Satyendra Nath Bose revolutionized the understanding of light and matter, sparked new ideas in Einstein, and left a great legacy in modern physics
“Respected sir,” began a letter that the then Nobel laureate and very famous Albert Einstein received one day in June 1924.
The letter came from the University of Dhaka, a city that was part of India British, so it was on the colonial periphery, far from the scientific center of the world where all established knowledge was being revolutionized.
“I have taken the liberty of sending you the enclosed article for your reading and opinion. I am eager to know what you think about it. If you consider the work worthy of publication, I would be grateful if you would arrange for its publication in Zeitschrift fur Physik.”
The German Zeitschrift fur Physik was one of the most important publications in the world in theoretical and experimental physics at that time.
Who was the author of this letter, and what had prompted him to make such a request?
He acknowledged himself as “a complete stranger” to Einstein, but noted: “I feel no hesitation in making such a request, for we are all your disciples.”
However, he revealed that it was not the first time he had written to him: “I don't know if you still remember that someone from Calcutta asked you for permission to translate your work on relativity into English. You agreed to that request. The book was published. I was the one who translated your work. mathematician Satyendra Nath Bose had found the solution to a problem that even Einstein hadn't been able to solve.
Within eight days, the master of relativity had already translated the article into German and sent it for publication to the journal Zeitschrift fur Physik,accompanied by a note in which he described it as “an important advance” and anticipated that he himself would expand upon these revolutionary ideas.
To Bose, he wrote a postcard confirming that his work was “an important step forward,” adding: “I am very pleased.”
That step forward kept becoming more and more enormous.
From the brief but significant collaboration between Einstein and Bose sprang pioneering knowledge in quantum science that continues to transform the world.
But Despite having contributed to changing the face of 20th-century science and, moreover, having worked with Marie Curie, inspired the poet Tagore, and frequented great scientists and artists, the Indian physicist is little known.
And it is a pleasure to get to know him.
110 out of 100
Bose was born on the first day of 1984 in Calcutta, into a family linked to the Bengali Renaissance, a movement that promoted modern education and cultural renewal in colonial India.
From a very early age, his intellect shone brightly.
Among the various stories circulating about his genius—some true, others perhaps embellished—is the tale of a teacher at his school who, impressed by one of his papers, awarded him a grade of 110 out of 100.
The teacher was convinced that his student would become a brilliant mathematician.
Bose, always curious about all kinds of intellectual and artistic creation, he did indeed end up choosing mathematics as his professional path.
And, like his friend, fellow student, and future astrophysicist Meghnad Saha, he was fascinated by theoretical physics, especially the new quantum theory that German physicists were exploring.
After graduating and becoming professors at the University of Calcutta, Bose and Saha embarked on an unusual task: translating into English the original works of Einstein and Hermann Minkowski on relativity, something that hadn't been done anywhere before.
Remember that in his letter to Einstein, Bose mentioned that he had written to him before?
Well, this was the reason: to avoid violating the great physicist's copyright, he requested special permission.
Einstein gladly granted it, and the book *The Principle of Relativity*, published in 1920, was the first collection in English of those fundamental articles.
More than a simple translation, it was a bridge to global knowledge, a gesture that facilitated the dissemination of revolutionary ideas at a time when scientific news took a long time to cross borders.
However, it was when Bose moved from Calcutta to the University of Dakar that he truly made history.with that article entitled “Planck's Law and the Quantum Hypothesis of Light” that he sent to Einstein.
It was like a key that unlocked the door to knowledge.
In parallel, and thanks to Einstein, Bose obtained a research license to travel to Europe and work with the best laboratories and researchers of the time.
The Amusing Encounter with Marie Curie
Bose arrived in Paris in October 1924 and quickly became involved in scientific circles, attending lectures and talks by figures such as the physicists Paul Langevin and Louis de Broglie.
Interested in learning experimental techniques with radioactivity, Langevin provided him with a letter of introduction to meet Marie Curie at the Radium Institute.
Bose recounted that, after greeting him “warmly,” she told him: “You will certainly have the opportunity to work with me, but not right now, rather in three or four months. First, you have to learn the language; Otherwise, you will find it difficult.” “It's difficult to get around in the laboratory.”
“She told me I should meet a beautiful French woman from whom I should learn. So we searched Paris for this lovely woman. The truth is, I knew French: I could read and write, but I couldn't tell Madame Curie because she talked nonstop.”
Bose found the whole humorous episode and, while waiting for the opportunity to formally join Curie's laboratory, he took advantage of his time in Paris to work with other researchers. and familiarize himself with cutting-edge techniques in experimental physics.
Among them was the French physicist Jacqueline Zadoc-Kahn Eisenmann, with whom he formed a deep friendship.
The correspondence between them portrays the vibrant intellectual exchanges of quantum physics at the time, as illustrated by this letter that Bose wrote to her from Berlin in 1925:
“My sweet Jacqueline, your quick reply made me happy, but mixed with There's a feeling of sadness in her: it makes me think of how little I saw you last day.
"It seems everyone in Berlin is very excited about the developments in physics."
"On the 1st and 28th of last month, [Werner] Heisenberg spoke at the colloquium about his theory. Everyone is very puzzled, and very soon there will be a discussion about the work of [Erwin] Schrodinger."
"Einstein seems very enthusiastic about it. The other day, on the train back from the colloquium, we found him jumping into the same compartment we were in, and he immediately began to speak passionately about what we had just heard."
"We all remained silent, while he spoke almost the entire time, unaware of the interest and fascination he aroused in the other passengers."
Back Home
Any physicist visiting Berlin in the 1920s must have felt a bit like a musician visiting Liverpool in the 1960s, commented physicist and science writer Sharon Ann Holgate in the BBC radio portrait of Bose, The Indian Particle Man.
Some of the brightest minds of the early 20th century were there, discussing the intricacies of the strange new quantum theory that seemed too bizarre to grasp.
“You'll never in your life have the chance to meet such great men of science,” Bose noted.
But India and his family were waiting for him.
On his return, Bose established himself as a central figure in the country's physics, combining teaching, research, and institutional almost leadership, and influencing generations of scientists.
One thing he strongly advocated was the importance of teaching science in India's native languages, rather than the English.
According to his grandson, Falguni Sarkar, who spoke to the BBC, Bose admired countries like Israel and Japan for having created a solid scientific culture and first-rate contributions based on the use of their own languages.
The idea, however, met with much resistance. The Indian physicist Partha Ghose, a disciple of Bose, recalled that one day he asked him why he insisted so much on that question, and that he received a “very convincing” answer.
“I don't think about people like you, who are dedicated to science,” Bose told him. “I think about the average Indian: why should he have to learn a foreign language to be able to understand the basic things that happen in science?”
His activity was not limited to science: he was also a humanist intellectual, deeply interested in music—particularly Indian classical music—literature, and art, and he actively participated in the cultural circles of his time, convinced that scientific creativity was part of a broader creative impulse.
But let's return to the scientific creativity of Bose and Einstein, and to that article.
Bose's Brilliance
At the end of the 19th century, physicists faced a seemingly simple problem: how does a hot object emit light? More precisely, how much light does it emit in each color depending on its temperature? If a metal is heated, how much red light does it produce? How much blue? How does this distribution change as the temperature increases?
Classical physics attempted to answer using the known laws of electromagnetism and thermodynamics… and failed spectacularly.
Its equations predicted that a body should emit an infinite amount of ultraviolet radiation, something that clearly did not happen. This theoretical absurdity was somewhat ironically dubbed, like the ultraviolet catastrophe.
The problem was profound: it wasn't an experimental error, but an internal contradiction in the theory. The same laws that successfully described the everyday world led here to mathematical nonsense.
Understanding how a hot body emits light wasn't a minor technical detail, but a sign that something fundamental was wrong with the very way we conceived of energy and radiation.
Solving it required changing the rules of the game.
In 1900, the German physicist Max Planck solved the enigma by proposing something radical for the time: energy wasn't exchanged continuously, but in small "packets" or quanta, whose size depended on the frequency of the radiation.
His formula accurately described how objects emit light according to their temperature.
What was truly profound wasn't just that it worked, but what it implied: energy was quantized. That break with classical physics opened the door precisely to quantum physics. A few years later, Einstein took the idea a step further and applied it directly to light, proposing that radiation itself traveled in quanta—photons—to explain phenomena that classical theory could not. Even so, the new physics was advancing on still unstable conceptual foundations. Planck's law worked perfectly, but its theoretical justification remained unsatisfactory, supported by assumptions inherited from classical physics that were proving increasingly fragile.
That's where Bose radically changed the approach.
He treated light not as a continuous wave, but as a collection of indistinguishable quanta, and counted their possible distributions without resorting to the conceptual artifices of classical physics.
The result was as simple as it was compelling: Planck's law emerged naturally, without patches or contradictions.
With this, Bose not only clarified the foundation of one of the most important formulas in modern physics, but also showed that the hypothesis of light quanta was not a provisional solution, but a central piece of a new way of understanding nature.
Einstein's Genius
Einstein understood it immediately.
He saw that Bose hadn't performed a mathematical trick, but had discovered a new way of counting, an unprecedented way of describing systems made up of indistinguishable particles.
And here came the surprising twist.
Einstein wondered: if this way of counting works for light, what happens if it's applied to matter?
In doing so, he predicted something completely unexpected: that at extremely low temperatures a large number of particles could collapse into a single quantum state, having as a single macroscopic object.
Thus, at least on paper,the Bose-Einstein condensate was born, popularly known as the fifth state of matter.
It took almost seven decades before scientists experimentally confirmed Einstein's prediction.
Today, the ideas of Bose and Einstein underpin cutting-edge technologies: from quantum computers to superconducting magnets used in magnetic resonance imaging and the large particle accelerators at CERN.
Even the mathematics of superconductivity inspired the ideas that led to the discovery of the Higgs particle and its role in the structure of the universe.
Although many of the discoveries inspired by this theoretical framework won Nobel Prizes, Bose himself did not receive such an award. His legacy, however, remains immortal in physics. His surname gave rise to the name of bosons, one of the two major families of fundamental particles, formed from "Bose" and the Greek suffix "-on," common in subatomic nomenclature. In the words of the eminent physicist and Einstein biographer, Abraham Pais (1982): "Bose's paper is the fourth and last of the revolutionary papers on the old quantum theory; the other three are by Planck, Einstein, and Bohr." Nothing less than the cream of the crop of physics that transformed our world!

