Science has an immense impact on understanding how nature works. The macroscopic world in which we live, feel, and see is governed by laws of classical physics. For example, Newton’s law, a celebrated law in classical physics, explains how an apple falls from a tree on the ground. However, there are phenomena that require a completely different thought process. This requires ideas in which one needs to invoke revolutionary concepts, such as the notion that the particles can be indistinguishable, energy can be quantized in small packets instead of being continuous, and light can consist of particles. These path-breaking ideas gave birth to the first Quantum revolution in the 20th century.
One such phenomenon is black body radiation, in which all incident radiation is absorbed, an example being the spectrum of light from the Sun during a solar eclipse. The classical laws cannot explain the experimentally measured spectra of black body radiation. While Wien’s displacement law explained the behaviour of low-frequency radiation and Rayleigh-Jeans law addressed the high-frequency end, there was no consistent theory that could explain the full spectrum. There was absolute desperation, and Max Planck put forward a groundbreaking idea in this context. He introduced the concept of oscillators that emit energy in discrete packets called ‘quanta’. Interestingly, Albert Einstein, in 1905, proposed the idea that radiation behaves like discrete quanta through a heuristic approach, for which he was awarded the 1921 Nobel Prize in Physics.
SN BOSE AND QUANTUM SCIENCE
In the middle of this intense activity happening in Europe, Satyendra Nath Bose was a modest man from undivided India whose contribution made a mark in the history of Quantum Science. Bose, the eldest son of Amodini Bose and Surendranath Bose, was born and raised in Calcutta. Bose was an extraordinary student, as evidenced by his exceptional academic credentials. He ranked first at the Calcutta University, while his distinguished classmate Meghnad Saha earned second place in the BSc and MSc examinations. Bose, who was first appointed a lecturer in Physics at Calcutta University, moved to the newly established Dacca University (now in Bangladesh) in 1921. At this time, Bose became deeply interested and inspired by the revolutionary new physics of Max Planck’s hypothesis of ‘quanta’ and Einstein’s quantisation of electromagnetism. Working as a Reader at Dacca University, he noticed a logical inconsistency in all the earlier derivations of Planck distribution while teaching his students. This led to a great discovery which added a new insight, namely the indistinguishability of particles, into the then-evolving quantum theory. Based on his work, Bose prepared a manuscript and sent it for publication to The Philosophical Magazine. However, he did not get any response from the magazine. In desperation, he sent a letter to Einstein along with the article with a request to translate it into German and get it published in Zeitschrift für Physik. Einstein took this letter received from an unknown Indian seriously, translated it into German, and sent it for publication in Zeitschrift für Physik with a strong recommendation. The paper was received by Zeitschrift für Physik on 2 July 1924 and was published in December 1924. Einstein wrote back-to-back articles in the same issue on the theory of ideal Bose gas and Bose-Einstein condensation, extending on Bose’s idea. Bose’s revolutionary insight that particles cannot be distinguished from one another, even if they occupy the same quantum state, led to the Bose-Einstein statistics and, consequently, the name BOSONs—the name coined by Paul Dirac to commemorate the contribution of Bose— for such particles. Examples include photons (quanta of light), He-4 atoms, hydrogen molecules, gluons, Higgs boson, etc. The indistinguishability of particles fundamentally alters the quantum mechanical wave function as these wave functions must be symmetrized—swapping two identical bosons does not change the overall state. This is in marked contrast to FERMIONs which obey Fermi-Dirac statistics and have quantum mechanical wave functions which are anti-symmetrized—swapping two fermions changes the overall state. Examples of fermions include electrons, protons, etc. A remarkable consequence of indistinguishability is the phenomena of Bose-Einstein condensation, where many bosons occupy the same lowest energy state at very low temperatures.
NOBEL PRIZES ON BOSE’S WORK
Bose’s paper is regarded as the final piece of the four groundbreaking publications that contributed to the development of new quantum mechanics, alongside those by Planck in 1900, Einstein in 1905, and Niels Bohr in 1913. Despite being nominated several times, Bose did not receive the Nobel Prize. Interestingly, however, several Nobel Prizes were later awarded for work related to the boson—the particles named after him. For example, the 2001 Nobel prize in Physics was awarded to Eric A Cornell, Wolfgang Ketterle and Carl E Wieman “for the achievement of Bose-Einstein condensation in dilute gases of alkali atoms, and for early fundamental studies of the properties of the condensates”. In 2013, the physics Nobel Prize was awarded to François Englert and Peter W Higgs “for the theoretical discovery of a mechanism that contributes to our understanding of the origin of the mass of subatomic particles”—namely Higgs boson.
All Images Courtesy: S.N. Bose National Centre for Basic Sciences
In recognition of his contributions to science, Bose was awarded the Padma Vibhushan by the Government of India in 1954, was elected a Fellow of Royal Society in 1958 and made a National Professor in 1959. He was the president of the Indian Science Congress and the Vice-Chancellor for Visva-Bharati, Santiniketan. He was nominated to the Rajya Sabha and honoured with doctorates from several esteemed universities. However, unlike other renowned scientists of the pre-independence era, such as Meghnad Saha, Homi Bhabha, P C Mahalanobis, and Shanti Swarup Bhatnagar, Bose did not focus on establishing major scientific institutions or research organisations.
Bose was an academically oriented intellectual person interested in different branches of science. Beyond his foundational work, Bose conducted research in various areas of physics, including crystallography, the ionosphere, and unified field theory. After returning from Europe, where Bose worked with Maurice de Broglie, he took an interest in building up the Crystallography activities at Dacca University. He set up laboratories and libraries to make the department a centre of research in X-ray spectroscopy, X-ray diffraction, magnetism, and optical spectroscopy. Bose designed the equipment himself in this laboratory. Besides, he took an interest in literature and music. His love for music was well-known. He used to play the esraj, which is parallel to Einstein’s love for the violin.
BOSE STATISTICS AND SECOND QUANTUM REVOLUTION
Along with developing new quantum statistics, Bose’s work also constitutes the foundation of novel technologies that also find applications in the Second Quantum Revolution, a topic of discussion today that is strongly backed by the Indian Government’s National Quantum Mission, launched in 2023. His work, especially on Bose-Einstein statistics, has had lasting impacts, fostering innovations that are particularly relevant today in the era of the second quantum revolution. This current revolution harnesses the puzzling rules of the quantum world to devise advanced information processing methods and develop new computing machines that surpass their classical counterparts in performance and efficiency. Globally, both private and public agencies are vigorously pursuing breakthroughs in this domain, aiming to unlock the full potential of quantum technologies.
S N Bose National Centre for Basic Sciences, an Autonomous Research Institute established under Department of Science and Technology (DST), Government of India in 1986 to honour the life and work of Professor S N Bose, celebrated the centenary of Bose’s colossal work in theoretical physics in 2024 by organising three international conferences and several outreach programmes throughout the year. While the conferences provided opportunities for experts across the globe to come together and exchange their ideas, the outreach programmes created momentum towards popularising science. Renowned scientists from research laboratories and universities all over the world, have come and spoken about their work, shared their views on the future of the second quantum revolution and interacted with students and young researchers to ignite their minds about the expanding horizons in quantum science and technology. The conferences had talks by Wolf prize winners, Buckley prize winners, Dirac medalists, Bardeen prize winners, Onsagar prize winners and Europhysics prize winners. Most importantly, several prominent Indian diaspora scientists from Princeton, Penn State, UIUC, Toronto, OSU, Harvard, UC Davis, Oxford, etc., attended the meeting.
PROMOTING SCIENCE IN MOTHER TONGUE
Inspired by Gurudev Rabindranath Tagore, Bose devoted considerable time to promoting science in his mother tongue. Tagore dedicated his book on science, Visva-Parichay or Introduction to the Universe, to Bose. In 1948, Bose set up Bangiya Vijnan Parishad, an institution for popularising scientific knowledge. Keeping this in mind, in the centenary celebration by S N Bose Centre, public lectures were organised in Bengali, with Bangiya Vijnan Parishad. Seminars and talks were also organised at colleges and universities all over West Bengal. Thousands of students have been reached through multiple outreach programmes. Other than Bangiya Vijnan Parishad, these programmes were organised in collaboration with the Indian Physics Association, a national-level organisation dedicated to popularising Physics.
Besides his scientific attributes, Prof Bose had a progressive mind compared to his time. In particular, for him, the gender of a researcher was never an important factor. Purnima Sinha, a promising Physics student at Calcutta University, joined her PhD programme in Prof Bose’s group. Purnima Sinha was the only woman in this group. Sophisticated instruments were built under Prof Bose’s active guidance. Purnima Sinha’s PhD work involved analysing clay from all over India. She was awarded the PhD degree in 1956, becoming the first Indian woman to earn a PhD degree in Physics from an Indian university. Interestingly, Prof Ashima Chatterji started her initial research on medicinal plant extracts with Prof Bose and conducted the first small molecule XRD, which was a pioneering work at that time. Even though women in science have earned firm ground under their feet today, their path has not been easy. The second conference of celebration of Bose statistics was thus dedicated to “Women in Quantum Science and Technologies” to bring under focus the challenges and achievements of the women scientists and their path-breaking work in modern day quantum science.
On a closing note, Bose altogether was a different person as compared to many other scientists of his level. He was not an ambitious man. Bose never felt any regret or bitterness about not being awarded the Nobel Prize, despite his significant contributions to science. He valued the respect and admiration from his peers and the scientific community more than any personal award, finding fulfilment in the impact his work had and the legacy he left behind. While we may regret the Missed Physics Nobel Prize, it is an exceptional recognition and perhaps enough that one of the two families of particles was named (bosons) after him. Among the educated society in Dacca at that time, Bose was looked upon as a young professor who no one else could understand except Einstein. According to Lev Landau’s logarithmic scale of productivity and genius, while Einstein was ranked 0.5, Bose was awarded a rank of 1 along with Niels Bohr, Werner Heisenberg, Paul Dirac and Erwin Schrödinger.
*Prof Tanusri Saha-Dasgupta is the Director of SN Bose National Centre for Basic Sciences, Kolkata, where Dr Saquib Shamim is an Assistant Professor at the Department of Condensed Matter and Material Physics.
