In the discipline of quantum physics, names like Albert Einstein and Niels Bohr often take centre stage. But there’s another figure who deserves as much recognition: Indian physicist Satyendra Nath Bose, whose pioneering work on particles indistinguishability revolutionised modern physics, introducing the concept of the particle later named “boson” in his honour, and laying the foundation for discoveries like the Higgs boson nearly a century later.
Now, as we commemorate 100 years of Bose-Einstein Statistics, it is incredible to see Bose’s legacy celebrated around the world. His work didn’t just shape the course of quantum mechanics, it changed how we understand the building blocks of the universe.
Born on January 1, 1894, in Calcutta (now Kolkata), Bose showed remarkable talent in mathematics from an early age. He graduated with top honours in physics from Presidency College. Despite weak eyesight, his passion for science marked him as one of India’s most promising young scientists.
Motivated by his teacher, Jagadish Chandra Bose, a pioneer in radio waves, Bose was inspired to explore the untapped potential of physics and ventured into quantum mechanics, where his contributions would immortalise his name.
In 1917, he began teaching physics and applied mathematics at the University College of Science, Calcutta, where he collaborated with physicist Meghnad Saha. Together, they published a paper on the kinetic theory of gases in Philosophical Magazine, developing molecular understanding in statistical mechanics.
Bose and Saha also translated Albert Einstein’s key works on relativity from German to English. This dedication to widening scientific knowledge became a defining feature of Bose’s career.
In the early 1920s, Bose was studying Max Planck’s quantum theory, which dealt with the energy distribution in blackbody radiation. Planck’s work was novel, but it relied on assumptions that Bose found dissatisfying. He believed that photons, particles of light, behaved in a way that was different from the particles of classical mechanics, which obeyed the laws of distinguishability. Stating the accepted norms to be absurd, Bose proposed a new way of counting particles in quantum states, particularly focusing on indistinguishable particles — an entirely new concept. In 1924, Bose wrote a paper, Planck’s Law and the Hypothesis of Light Quanta, in which he derived Planck’s radiation law without any classical assumptions. He developed a method to treat photons as indistinguishable particles, laying the foundation for what would later be called Bose-Einstein Statistics. Bose submitted his paper to a prestigious British journal, only to face rejection. Undeterred, he decided to send his work directly to Albert Einstein, then the world’s leading physicist, with this letter: “If you think the paper is worth publication, I shall be grateful if you arrange for its publication in Zeitschrift für Physik. Though a complete stranger to you, I do not feel any hesitation in making such a request. Because we are all your pupils though profiting only by your teachings through your writings.”
Einstein recognised the significance of Bose’s work almost immediately. Not only did he arrange for its publication in the Zeitschrift für Physik, but he also expanded Bose’s ideas, applying the new statistics to atoms and predicting a remarkable state of matter that would later be known as the Bose-Einstein Condensate (BEC). This novel state occurs when particles occupy the same quantum state, resulting in quantum phenomena observable on a macroscopic scale. Einstein’s enthusiastic endorsement of Bose’s work helped propel Bose’s statistics into mainstream physics, cementing his legacy.
Though his name was now linked with a revolutionary theory, Bose’s work did not immediately grant him fame or accolades. In 1924, Einstein extended Bose’s statistics without seeking Bose’s input, and in two of his subsequent papers, he even incorrectly credited the concept to another scientist, Debendra Mohan Bose. This oversight, combined with the geographical and cultural divide between Bose and the scientific establishment, delayed full recognition of his contributions. After a stint in Dhaka, Bose spent two years in Europe, 1924 to 1926, initially intending to work with Einstein in Berlin. However, by the time he arrived, Einstein had moved on to other research areas, focusing on the unification of electromagnetic and gravitational fields. Despite this missed opportunity, Einstein provided letters of introduction that allowed Bose to connect with prominent European physicists.
Upon his return to India, Bose continued his academic career, eventually becoming head of the physics department at Dhaka University. Here, he introduced novel ideas in quantum mechanics and statistical physics, inspiring a new generation of Indian physicists. Later, in 1945, he joined Calcutta University, where he spent the remainder of his career advancing scientific education and research in India. Despite his academic success, Bose faced challenges, such as the lack of resources and resistance from conservative faculty members at Santiniketan, where he briefly taught.
Bose’s work laid the foundation for several important discoveries in quantum mechanics. The BEC concept, predicted in the 1920s, remained theoretical until 1995, when scientists Eric Cornell and Carl Wieman created the first BEC in a lab using rubidium atoms. Their work, along with Wolfgang Ketterle’s research, earned the Nobel Prize in Physics in 2001 and validated Bose’s ideas, demonstrating the quantum behaviour of particles on a macroscopic scale.
In a broader sense, Bose’s contributions were fundamental in distinguishing between two classes of particles in the quantum realm: bosons and fermions. Bosons, named in Bose’s honour by physicist Paul Dirac, follow Bose-Einstein statistics and can occupy the same quantum state, enabling phenomena like superconductivity and superfluidity. Fermions, in contrast, obey the Pauli exclusion principle and cannot occupy the same state, giving rise to the structure of matter.
Although Bose was nominated for the Nobel Prize, he never received it. His work was foundational, but like many scientists from outside the Western world, he struggled for recognition. Despite this, Bose’s contributions remain an integral part of physics. His work with Einstein is celebrated as a turning point in quantum theory, and the impact of Bose-Einstein statistics extends beyond physics to fields like cosmology and condensed matter science. As we witness modern physics evolving with discoveries like the Higgs boson and advancements in quantum computing, Bose’s pioneering work on particle indistinguishability and quantum statistics remains more relevant than ever.
Nearly 50 years after his death, his legacy lives on in the institutions named in his honour and his name continues to inspire, representing a scientist who broke boundaries and laid the groundwork for discoveries that continue to shape our understanding of the universe.
Nishant Sahdev is a theoretical physics researcher and research affiliate at the University of North Carolina, Chapel Hill, the United States. The views expressed are personal
