Category: science

More is Different – A Brief Overview

P.W. Anderson (image from wikipedia)

In 1972, P. W. Anderson wrote what is considered one of the most remarkable essays in the history of physics, and the title of that essay is “More is Different.” In the essay, Anderson was trying to make a case for emergence, where new, interesting physical properties can emerge by the combination of matter, which you would not anticipate if you had just kept it as an individual entity.

One of the aspects related to this essay is also the thought that reductionism has its limitations and that groups act very differently compared to individuals. The higher-level rules that can emerge from the combination of small entities are actually very different from the rules that are applicable to individual entities.

For example, if you consider electrons in a solid, you have the emergence of properties of electrons such as magnetism or superconductivity, or, for that matter, putting molecules inside a compartment and, lo and behold, life arises out of that. This has turned out to be one of the most influential ways of thinking in physics because it opened up a new avenue for understanding complex systems not as just combinations of simple systems but as the emergence of properties.

Very interestingly, this essay does not actually mention the word “emergence” at all, but the concept is so fascinating that it has turned out to be one of the most influential essays ever written in physics. The whole point about this particular essay is that the whole is more than the sum of its parts, and P. W. Anderson has to be remembered for this magnificent essay.

Quartet of Modern World

Recently, I read an essay by James Read, a philosopher of physics at Oxford, in Aeon magazine.

The title of the essay is Why Philosophy of Physics?

It is a good read, and addresses a pertinent question of highlighting the role of philosophy of physics within the larger umbrella of physics as a discipline and human endeavor. Although the viewpoint and examples are mainly from theoretical physics, it makes a good case for the philosophy of physics.

Below are my thoughts:

I would add that both theoretical and experimental approaches to physics do raise philosophical questions that may be complementary, and in certain cases, necessary, to get a complete picture of the underlying physics.

I would go further and add that the foundations and approaches to engineering and its philosophy cannot be fully appreciated without grasping the underlying physics. This thought can be extrapolated to include mathematics, chemistry and biology too.

Engineering beautifully extracts knowledge from all the branches of science and puts them into use in the noisy world. By interacting with the external noise, it showcases the resilience and limitations of the foundational principles. Thus, it further motivates philosophical questions that will have to be addressed, going back to the first principles of science.

In that sense, science, technology, and philosophy form a trinity of ideas, each feeding the other, and sometimes creating a sum that is greater than its parts. To capture this evolution, we need the tools of history and hence a case for the history of science.

Together with history and philosophy of science, science and technology make an essential quartet. Our modern world stands on this quartet.

YouTube as an Archival Source

There are several models for using YouTube. One of them is to use it as a substitute for television and media outlets. This is where the number of views, subscriptions, and reach becomes important.

Another model is to harness YouTube as an archival source that is open to the public. This is one of the crucial elements of a platform that is easily accessible and, importantly, searchable. Such a platform becomes a repository for many informal academic discussions and interactions.

The archive model is an important category, especially if there is no need to generate revenue from the content deposited on the platform. A crucial aspect is that it can be accessed across the world and, in that sense, represents truly open-access content without paywalls, publication charges or subscriptions. Therefore, I am glad to see that many Indian academic programs, including NPTEL, ICTS, Science Activity Center/Media Center at IISER-Pune and many others are utilizing platforms such as YouTube to post their lectures and talks. Also, many individual academics in India are gradually using YouTube to discuss their work, in the context of research, teaching and entrepreneurship.

This development is slowly turning out to be an invaluable resource that can reach a large audience. Although YouTube is one of the most well-known platforms, many other platforms in the context of social media can also be tapped to spread knowledge. Given their reach and simplicity of use, both for creators and users, these tools become important in a vast country such as India.

As audio-visual public platforms join hands with artificial intelligence tools, they can positively (hopefully) affect how people, especially students, consume educational content. Going forward, I anticipate language translation through direct dubbing to be a game-changer. It could attract many new viewers who have been hesitant to watch technical content simply because it was in a foreign language. Of course, on these platforms, the noise is equally high compared to the signal, and therefore, curating good, targeted resources will be vital. Also, these platforms cannot be treated as a substitute for formal education, but as an extension or complementary source for research and education.

Interesting times ahead.

15 years at IISER Pune – Journey so far

Today, I complete 15 years as a faculty member at IISER-Pune. I have attempted to put together a list of some lessons (based on my previous writings) that I have learnt so far. A disclaimer to note is that this list is by no means a comprehensive one, but a text of self-reflection from my viewpoint on Indian academia. Of course, I write this in my personal capacity. So here it is..

  1. People First, Infrastructure Next
    As an experimental physicist, people and infrastructure in the workplace are of paramount importance. When I am forced to prioritize between them, I have chosen people over infrastructure. I am extremely fortunate to have worked with, and continue to work with, excellent students, faculty colleagues, and administrative staff members. A good workplace is mainly defined by the people who occupy it. I do not neglect the role of infrastructure in academia, especially in a country like India, but people have a greater impact on academic life.
  2. Create Internal Standards
    In academia, there will always be evaluations and judgments on research, teaching, and beyond. Every academic ecosystem has its own standards, but they are generalized and not tailored to individuals. It was important for me to define what good work meant for myself. As long as internal standards are high and consistently met, external evaluation becomes secondary. This mindset frees the mind and allows for growth, without unnecessary comparisons.
  3. Compare with Yourself, Not Others
    The biggest stress in academic life often arises from comparison with peers. I’ve found peace and motivation in comparing my past with my present. Set internal benchmarks. Be skeptical of external metrics. Strive for a positive difference over time.
  4. Constancy and Moderation
    Intellectual work thrives not on intensity alone, but on constancy. Most research outcomes evolve over months and years. Constant effort with moderation keeps motivation high and the work enjoyable. Binge-working is tempting, but rarely effective for sustained intellectual output.
  5. Long-Term Work
    We often overestimate what we can do in a day or a week, and underestimate what we can do in a year. Sustained thought and work over time can build intellectual and technical monuments. Constancy is underrated.
  6. Self-Mentoring
    Much of the academic advice available is tailored for Western systems. Some of it is transferable to Indian contexts, but much of it is not. In such situations, I find it useful to mentor myself by learning from the lives and work of people who have done extraordinary science in India. I have been deeply inspired by many people, including M. Visvesvaraya, Ashoke Sen, R. Srinivasan, and Gagandeep Kang.
  7. Write Regularly—Writing Is Thinking
    Writing is a tool to think. Not just formal academic writing, but any articulation of thought, journals, blogs, drafts, clarifies and sharpens the mind. Many of my ideas have taken shape only after I started writing about them. Writing is part of the research process, not just a means of communicating its outcomes.
  8. Publication is an outcome, not a goal Publication is just one outcome of doing research. The act of doing the work itself is very important. It’s where the real intellectual engagement happens. Focus on the process, not just the destination.
  9. Importance of History and Philosophy of Physics
    Ever since my undergraduate days, I have been interested in the history and philosophy of science, especially physics. Although I never took a formal course, over time I have developed a deep appreciation for how historical and philosophical perspectives shape scientific understanding. They have helped me answer the fundamental question, “Why do I do what I do?” Reflecting on the evolution of ideas in physics—how they emerged, changed, and endured—has profoundly influenced both my teaching and research.
  10. Value of Curiosity-Driven Side Projects
    Some of the most fulfilling work I’ve done has emerged from side projects, not directly tied to funding deadlines or publication pressure, but driven by sheer curiosity. These projects, often small and exploratory, have helped me learn new tools, ask new questions, and sometimes even open up new directions in research. Curiosity, when protected from utilitarian pressures, can be deeply transformative.
  11. Professor as a Post-doc
    A strategy I found useful is to treat myself as a post-doc in my own lab. In India, retaining long-term post-docs is difficult. Hence, many hands-on skills and subtle knowledge are hard to transfer. During the lockdown, I was the only person in the lab for six months, doing experiments, rebuilding setups, and regaining technical depth. That experience was invaluable.
  12. Teaching as a Social Responsibility
    Scientific social responsibility is a buzzword, but for me, it finds its most meaningful expression in teaching. The impact of good teaching is often immeasurable and long-term. Watching students grow is among the most rewarding experiences in academia. Local, visible change matters.
  13. Teaching Informally Matters
    Teaching need not always be formal. Informal teaching, through conversations, mentoring, and public outreach, can be more effective and memorable. It is free of rigid expectations and evaluations. If possible, teach. And teach with joy. As Feynman showed us, it is a great way to learn.
  14. Foster Open Criticism
    In my group, anyone is free to critique my ideas, with reason. This open culture has been liberating and has helped me learn. It builds mutual respect and a more democratic intellectual space.
  15. Share Your Knowledge
    If possible, teach. Sharing knowledge is a fundamental part of academic life and enriches both the teacher and the learner. The joy of passing on what you know is priceless.
  16. Social Media: Effective If Used Properly
    Social media, if used responsibly, is a powerful tool, especially in India. It can bridge linguistic and geographical divides, connect scientists across the world, and communicate science to diverse audiences. For Indian scientists, it is a vital instrument of outreach and dialogue. My motivation to start the podcast was in this dialogue and self-reflection.
  17. Emphasis on Mental and Physical Health
    In my group, our foundational principle is clear: good health first, good work next. Mental and physical well-being are not optional; they are necessary conditions for a sustainable, meaningful academic life. There is no glory in research achieved at the cost of one’s health.
  18. Science, Sports, and Arts: A Trinity
    I enjoy outdoor sports like running, swimming, and cricket. Equally, I love music, poetry, and art from all cultures. This trinity of pursuits—science, sports, and the arts—makes us better human beings and enriches our intellectual and emotional lives. They complement and nourish each other.
  19. Build Compassion into Science
    None of this matters if the journey doesn’t make you a better human being. Be kind to students, collaborators, peers, and especially yourself. Scientific research, when done well, elevates both the individual and the collective. It has motivated me to humanize science.
  20. Academia Can Feed the Stomach, Brain, and Heart
    Academia, in its best form, can feed your stomach, brain and heart. Nurturing and enabling all three is the overarching goal of academics. And perhaps the goal of humanity.

My academic journey so far has given me plenty of reasons to love physics, India and humanity. Hopefully, it has made me a better human being.

Einstein – Science and its History & Philosophy

I have been interested in the views of Einstein related to the history and philosophy of science (HPS). The more I read about his work, the more I find that his inclination is to combine science with its historical and philosophical evolution. I am in search of his correspondence with fellow scientists and intellectuals, and have been looking at clues towards this combinational approach to science.

The above image is the title of the Physics Today article.

Recently, I came across an article in Physics Today1 that reproduced a part of Einstein’s letter2. Here it is:

I fully agree with you about the significance and educational value of methodology as well as history and philosophy of science. So many people today—and even professional scientists—seem to me like someone who has seen thousands of trees but has never seen a forest. A knowledge of the historic and philosophical background gives that kind of independence from prejudices of his generation from which most scientists are suffering. This independence created by philosophical insight is—in my opinion—the mark of distinction between a mere artisan or specialist and a real seeker after truth

It is clear that Einstein liked this combination and thought that it should be part of one’s scientific education. There is a lot more on this topic in the Physics Today article, and it is an excellent read to understand the thoughts of Einstein on this topic. More on this in a future blog…

  1. Howard, Don A. “Albert Einstein as a Philosopher of Science.” Physics Today 58, no. 12 (December 1, 2005): 34–40. https://doi.org/10.1063/1.2169442. ↩︎
  2. A. Einstein to R. A. Thornton, unpublished letter dated 7 December 1944
     (EA 6-574), Einstein Archive, Hebrew University, Jerusalem ↩︎

From Yukawa Archives: a draft, a letter & a rejection

I have been amazed to explore the archives on Hideki Yukawa, which have been systematically categorized and meticulously maintained by Osaka University in Japan. My sincere thanks and acknowledgment to the Yukawa Memorial.

Below are a few gems from their public archives :

  1. Draft of the paper written in 1934 – The making of the groundbreaking paper of Yukawa, which eventually led to his Nobel Prize in 1949.

The archive draft is accompanied by a note which reads:

Yukawa had not published any paper before then. In 1933, Yukawa began working at Osaka Imperial University and tackled the challenge of elucidating the mystery of nuclear forces while Seishi Kikuchi and other prominent researchers were producing achievements in nuclear physics and quantum physics. The idea of γ’ (gamma prime) that Yukawa came up with in early October led to the discovery of a new particle (meson) that mediates nuclear forces. The idea of introducing a new particle for the purpose of explaining the forces that act between particles was revolutionary at that time. Yukawa estimated the mass of the new particle and the degree of its force. No other physicists in the world had thought of this idea before.

2. Letters between Tomonaga and Yukawa

Sin-Itiro Tomonaga was a legendary theoretical physicist from Japan, who independently formulated the theory of quantum electrodynamics (apart from Feynman and Schwinger) and went on to win the Nobel Prize in physics in 1965.

Tomonaga was a friend and classmate of Yukawa, and they inspired each other’s work. Below is a snapshot of the letter from 1933 written in Japanese.

Both these theoreticians were intensely working on interrelated problems and constantly exchanged ideas. The archival note related to the letter has to say the following:

During this period, Yukawa and Tomonaga concentrated on elucidating nuclear forces day in and day out, and communicated their thoughts to each other. In this letter, before starting the explanation, Tomonaga wrote “I am presently working on calculations and I believe that the ongoing process is not very interesting, so I omit details.” While analyzing the Heisenberg theory of interactions between neutrons and protons, Tomonaga attempted to explain the mass defects of deuterium by using the hypothesis that is now known as Yukawa potential. The determination of potential was arbitrary and the latest Pegrum’s experiment at that time was taken into consideration. Tomonaga also compared his results with Wigner’s theorem and Majorana’s theory.

3. Rejection letter from Physical Review

Which physicist can escape a rejection from the journal Physical Review?

Even Yukawa was not spared :-) Below is a snapshot of a rejection letter from 1936, and John Tate does the honours.

The influence of Yukawa and Tomonaga can be seen and felt at many of the physics departments across Japan. Specifically, their influence on nuclear and particle physics is deep and wide, and has inspired many in Japan to do physics. As the archive note says:

Yukawa and Tomonaga fostered the theory of elementary particles in Japan from each other’s standpoint. Younger researchers who were brought up by them, so to speak, must not forget that the establishment of Japan’s rich foundation for the research of the theory of elementary particles owes largely to Yukawa and Tomonaga.

4. Lastly, below is a picture of the legends from the archive: Enrico Fermi, Emilio Segrè, Hideki Yukawa, and James Chadwick.

From the archive note on the picture from September 1948:

Yukawa met Prof. Fermi and other physicists of the University of Chicago who were staying in Berkeley for the summer lectures. From the left: Enrico Fermi, Emilio Segrè, Hideki Yukawa, and James Chadwick.

Tomorrow, I will conclude my third trip to Japan. I always take a lot of inspiration from this wonderful country. As usual, I have not only met and learnt a lot from contemporary Japanese researchers, but also have metaphorically visited the past masters who continue to inspire physicists like me across the world.

For this, I have to say: Dōmo arigatōgozaimasu !

Where Ideas Merge: A Visit to the Institute of Science Tokyo

With Prof. Daiki Nishiguchi

New ideas are often created by the merging of two old ideas. How often is this true, and how often do we tend to forget this?

Today I visited the Institute of Science Tokyo, formerly known as Tokyo Tech. This is a new avatar of a very interesting institution funded by the government of Japan. By merging the Tokyo Institute of Technology with the Tokyo Medical and Dental University, a very interesting concept has emerged: the Institute of Science Tokyo. These two institutions have been important pillars of the research and educational landscape of Tokyo, and I had the privilege of visiting this new place, which is a result of a new merger.

Thanks to the invitation and fantastic hospitality of Prof. Daiki Nishiguchi, a faculty member in the Physics Department of the Institute of Science Tokyo, I had a memorable experience. I met Daiki a couple of years ago at the University of Tokyo, where he previously held a faculty position. Recently, he has moved to the Institute of Science Tokyo to establish his independent research group as an Associate Professor.

Daiki has done amazing work on topological soft matter, and his recent results include remarkable observations related to turbulence and vorticity in suspensions of bacteria under spatial confinement. He has also been setting up interesting experiments involving Janus particles, and I got a nice overview of his work. Thanks to him and his research group, I got a flavor of the research being carried out in their lab, and I was also treated to a wonderful lunch by Daiki.

I gave a physics seminar on some of our work on structured light and confinement of soft matter, especially thermally active colloidal matter in optothermal potentials. Since Daiki and his group (see image below) have expertise in topological soft matter, my seminar emphasized structured topological beams, including ring optical beams and optical vortices. I gave an overview of our experimental results and highlighted the prospect of utilizing the topology of light to interact with topological soft matter.

There is much to explore at this interface, and again, it brings me back to the point that new ideas often emerge from the merging of evolving old ideas, such as topological light and topological soft matter.

This is my third visit to Japan, and I always find their calm, focused, and deeply committed research environment inspiring. There is much to learn from their approach to science and technology, and my visit to the Institute of Science Tokyo reinforced this thought.

I thank Daiki and his research group for the wonderful time I had at their laboratory and offer my best wishes to him in his new explorations.

Book alert – Science, Pseudoscience, and the Demarcation Problem

There is a new book (88 pages) on the philosophy of science that discusses the demarcation problem between science and pseudoscience. The topics look interesting, and have relevance in a day and age where science has been appropriated for various purposes, including spirituality.

One will have to ask how to differentiate science from something that may sound like science but, with further exploration, turns out to be a hoax?

This book tries to address this issue from a philosophical viewpoint.

The book is free to read for 2 weeks (starting 9th March 2025).

Article on Gerhard Herzberg

The October 2024 issue of Resonance, Journal of Science Education

highlights the life and science of Gerhard Herzberg.

He was one of the greatest molecular spectroscopists who laid the foundation of atomic and molecular quantum mechanics and deeply impacted molecular astrophysics and astrochemistry.

He lived an extraordinary life, first in Europe learning quantum mechanics and then escaping 1930s Germany as his wife was of Jewish origin. Then, he settled in Canada to build and lead his lab, which was considered the ‘mecca of spectroscopy’ at NRC, Ottowa.

I wrote a sci-biography article about him in this issue

Link to full edition: https://www.ias.ac.in/listing/articles/reso/029/10

If you don’t know – Resonance is a pedagogical journal published by the Indian Academy of Sciences. It is a true open-access journal. Free to read and does not charge the authors to publish.

Do explore the past editions. There are some absolute gems. https://www.ias.ac.in/listing/issues/reso