Saha and Bose translate Einstein

In physics, the general theory of relativity is one of the most remarkable achievements. It has turned out to be one of the most profound theories in the history of physics. In 1916, Albert Einstein proposed this theory, and it was confirmed in 1919.

Right after this confirmation, around 1920, two Indian gentlemen named Satyendranath Bose and Meghnad Saha translated Einstein’s German work into English. What you are seeing as an image is the remarkable book Principles of Relativity, containing the original papers by Einstein and Minkowski. This translation was done by M.N. Saha and S. N. Bose, who were then at the University College of Science, Calcutta University. It was published in 1920 by the University of Calcutta.

The book also contains a historical introduction by Mahalanobis, the celebrated statistician, although he was originally trained as a physicist himself. This historical introduction is itself quite remarkable.

If you look at the table of contents of this book, you will find the following:

  1. A historical introduction.
  2. The Electrodynamics of Moving Bodies, which is an important paper and is necessary for understanding what follows.
  3. A short biographical note on Albert Einstein was written by Saha.
  4. The Principle of Relativity, mainly the Minkowski papers, translated by Saha, along with an appendix.
  5. The General Principles of Relativity, Einstein’s epoch-making 1916 paper, translated by S. N. Bose, followed by notes by these gentlemen.

The historical introduction discusses the evolution of ideas that led to the fruition of the general theory of relativity. This turned out to be one of the most important expositions of the general theory of relativity, soon after the emergence of the theory and its subsequent confirmation by Eddington through his famous solar eclipse expedition. This is a remarkable document, and it is available on the Internet Archive.

Quantum Optics course – thoughts and notes

Jan 2026 – Apr 2026 – I am teaching a course on Quantum Optics. Below you will find some random thoughts and notes related to my reading. I will be updating the list as I go along the semester. You can add your comments below.

  1. Anyone interested in physics should know a bit about renormalized QED and the efforts that went behind it… It still remains a benchmark of how experiments and theory work in elevating each other…
    • Hari Dass (erstwhile, IMSc) on FB made an interesting observation:it’s unfortunate that after all those and subsequent developments, a mystery is being built out of renormalisation..it was the price to pay for assuming, without any justification, that the microscopic description held to arbitrarily small distances..wilson,schwinger and even feynman have clarified that the right way to do physics is to start with an effective description with a cutoff, which can be fully quantum in nature, and keep extending it to higher and higher scales with the help of further data, as well as with better theoretical understanding..
  2. “The photon is the only particle that was known as a field before it was detected as a particle.” 
    • This is how Weinberg introduces the birth of quantum field theory. He further adds:  “Thus it is natural that the formalism of quantum field theory should have been developed in the first instance in connection with radiation and only later applied to other particles and fields.”Ref: S. Weinberg (in Quantum Theory of Fields, p.15,  1995)
      • Sudipta Sarkar (IIT G) made an interesting observation in facebook:
        • In some sense, it did right! Dirac started QFT with the effort to quantise radiation! But formally, it is not easy to write down the quantum version of electrodynamics owing to gauge symmetry. It took quite a bit of time to understand how to manage a quantum theory with massless states!
        • My reply: “indeed..the reconciliation of symmetry was a bottleneck. I am also amazed by the progress of thought, especially by Dirac, who took the harmonic oscillator problem and treated it the way he did. Historically, the question of quantization of particles was already an established programme, but to quantize the field was indeed a major challenge, and hence ‘second quantization’.
        • The concept of creation and annihilation operators is an intriguing one because it brings in the thoughts from the commutation relationship that existed in classical physics and transfers that into quantum mechanics. This intellectual connection is mainly attributed to Dirac, and historically, this has been one of the most important connections to be made. The question of field quantization already existed in 1920s, but it is thanks to Dirac who really made this connection in a systematic and mathematically consistent way.
  3. In the context of the quantum harmonic oscillator model of electromagnetic radiation, the shift from canonical variables such as position and momentum to creation and annihilation operators is a fascinating one. Interestingly, this progression further leads to the so-called number operator. It is also a progression from Hermitian to non-Hermitian and again back to a Hermitian operator. In the process of understanding the number operators, one realizes that the ground-state results in the so-called zero-point energy. Taken further, the commutation of the number operator with the electric field of the electromagnetic radiation results in the number-amplitude uncertainty. This further gives an insight into why the field amplitude has a non-zero spread, even for the n = 0 state, and therefore results in the so-called vacuum fluctuations.
    • It can’t get more quantum than this…
  4. An essay on Quantum States in Argand Diagrams: https://historyofscience.in/2026/02/03/quantum-states-in-argand-diagrams-vacuum-coherent-and-squeezed/

Hedi Born’s picture

This is Hedi Born (wife of Max Born) sending a picture with a note to Lokasundari Ammal (CV Raman’s wife) in 1937.

Max Born and his family spent some time at IISc, Bangalore, in 1935-36.

Amazing to see how communication channels have changed, but the human urge to communicate remains the same..

picture source: (Venkataraman, G.; Journey into Light: Life and Science of C.V. Raman. Indian Academy of Sciences, 1989. p. 364)

Conversation with Chaitanya Athale

Chaitanya is a professor of biology at IISER Pune and works on quantifying biology at the cellular scale. His lab focuses on cytoskeleton and cell shape research and explores synthetic biological roots to address a variety of questions at the cellular scale.

In this freewheeling conversation, we talked about quantitative biology in his lab, reading, the German language, his recent comic-themed book, and a bit on philosophy of biology as we explored his intellectual journey. Also, don’t miss the 3D model he shows to explain his research.

References with links:

‘Chaitanya Athale – IISER Pune’. Accessed 3 January 2026. https://www.iiserpune.ac.in/research/department/biology/people/faculty/regular-faculty/chaitanya-athale/6.

‘Dr. Chaitanya Athale – Lab – Cytoskeleton and Cell Shape Research – Synthetic Biology’. Accessed 3 January 2026. https://sites.iiserpune.ac.in/~cathale/.

‘‪Chaitanya Athale – ‪Google Scholar’. Accessed 3 January 2026. https://scholar.google.com/citations?user=Volq2gEAAAAJ&hl=en.

Chaitanya Athale | LinkedIn’. Accessed 3 January 2026. https://www.linkedin.com/in/chaitanyaa/?originalSubdomain=in.

Arias, Alfonso Martinez. The Master Builder: How the New Science of the Cell Is Rewriting the Story of Life. Basic Books, 2023.

 ‘Athale Lab: CyCelS 💉💉💉💉🚲🤿⛵ (@AthaleLab) / X’. 9 January 2025. https://x.com/athalelab.

Raman essay and Open-Access

I see that the essay I wrote on CV Raman and made open access (thanks to Resonance, which published it) has been used by several educators on YouTube, including some in Indian languages. Also, the Google AI overview shows the published essay as the main reference for a search related to Raman’s science communication (see slideshow below).

I am glad to see that making one’s writing open to all has positive effects. Open-access, not just for readers, but also for authors, is beneficial. Especially in India, paywalls for science are a detriment.

My worry is that open-access publishing has been mainly driven by commercial publishers that extract huge funds from the publishing authors. This defeats the purpose of open science, especially when the research of an author is publicly funded. Added to that, Indian researchers and writers cannot afford to pay huge sums for publishing articles and books.

The publication landscape (including journals and books) across the world needs an introspection. Open-access model is effective only when the readers and authors have access to that model. Otherwise, the model becomes a paywall for authors.

Conversation with A.R.Venkatachalapathy

Welcome to the podcast, Pratidhavani – Humanizing Science

A. R. Venkatachalapathy is a prolific historian, writer and Professor whose work explores the social and cultural history of colonial Tamil Nadu. In 2024, he was awarded the Sahitya Akademi Award. 

His notable books include “In Those Days There Was No Coffee,” “The Province of the Book,” “Tamil Characters,” and “Swadeshi Steam,” which examines V.O. Chidambaram Pillai’s role in anti-colonial maritime resistance. His scholarship spans Tamil literature, publishing history, and intellectual culture, blending rigorous archival research with literary analysis.

In this episode, we explore his intellectual journey as a historian and bilingual author.

History of Maths in India – a good book

In recent years, this has been one of the best books on the history of mathematics in India. The late Prof. Divakaran was a theoretical physicist and a scholar.

This book is also an excellent example of how a scientist can present historical facts and analyse them with rigour and nuance. Particularly, it puts the Indian contribution in the global context and shows how ideas are exchanged across the geography. The writing is jargon-free and can be understood by anyone interested in mathematics.

Unfortunately, the cost of the book ranges from Rs 8800 to Rs 14,000 (depending on the version), which is a shame. Part of the reason why scholarly books, particularly in India, don’t get the traction is because of such high cost. This needs to change for the betterment and penetration of knowledge in a vast society such as India.

There is a nice video by numberphile on Prof. Divakaran and his book: