The Knowmads Podcast

The Knowmads

This podcast is about Science, Technology, Engineering, Mathematics, Music, Philosophy, Culture, Graduate life and much more. 

  1. 1D AGO

    Ashmeet Singh on a Quantum-First Approach to Space, Time, Gravity, and Cosmology

    In the 1920s, physicists like Schrödinger, Heisenberg, Einstein, Planck—and many others—realized something deeply unsettling and beautiful: the universe at microscopic scales is nothing like what we observe in everyday life. This was the era when quantum mechanics was discovered. And I’m intentionally saying discovered, not born, because that word choice matters. Quantum mechanics isn’t just a framework we invented—it’s closer to the idea that we uncovered something that was already true about reality. What makes this discovery so fascinating is that quantum mechanics feels so far away from how we perceive the world… and yet, it is literally what the world is. The universe is fundamentally governed by quantum laws. And what we experience in daily life—objects with definite properties, predictable motion, a world that feels stable and classical—can be thought of as an emergent phenomenon. And the way we’re taught physics reflects that. When we start learning physics in high school, we begin with the rules of the world we directly experience: classical physics. Only later do we “upgrade” to quantum mechanics, and we try to map our classical intuition onto this quantum world. And we do that for a very human reason: from birth, we’ve trained our intuition on the classical world. So when quantum mechanics tells us something that doesn’t match that intuition, it feels non-intuitive. But what if we flipped the script? If the universe is fundamentally quantum, why don’t we start there? Why don’t we build our intuition from the quantum picture first—and then understand classical reality as something that emerges in the right circumstances? That question—this idea of taking a quantum-first approach—is exactly what our guest today, Ashmeet Singh, is thinking about. Ashmeet is a theoretical physicist who completed his PhD at Caltech and is now a professor of physics at the Indian Institute of Technology, Delhi. Along with being a brilliant physicist, Ashmeet is also an avid science communicator—someone who has a real gift for explaining complex ideas in physics in a way that’s clear, intuitive, and genuinely exciting. In this episode, we also talk to Ashmeet about his personal journey through academia: how he navigated his path from IIT to Caltech to IIT, what that transition felt like, and what he learned along the way about doing research, and finding a place in physics. We’re genuinely grateful to IIT Delhi for hosting us—both giving us this beautiful space to sit in and record and for inviting us to give colloquium talks while we were in India. And a special thanks to Saarthak Parik for being a wonderful host and organizing everything so smoothly. So if you’ve ever wondered what it would mean to understand the universe starting from quantum mechanics—treating classical reality not as the default, but as the thing that has to be explained—then you are in for a treat.  Ashmeet's Website: https://www.quantumfirst.space/ Ashmeet's Youtube (The Scribbled Equation): https://www.youtube.com/@TheScribbledEquation

    1h 37m
  2. MAR 23

    Piotr Sułkowski on Mathematical aspects of Theoretical Physics

    Recently, I came across a definition of a good theory: it should explain as much as possible, with as few ingredients as possible, and with as much accuracy as possible. I think that is something every serious physicist can relate to. And really, that is what modern theoretical physics is striving for — not just identifying what the universe is made of, but understanding the mathematical framework that makes the laws of nature hang together. That is why the mathematical formulation of quantum field theory is so important. It reveals the hidden structures behind particles, forces, symmetry, and even space itself, and it opens surprising connections to geometry, topology, and information. That is precisely the kind of frontier our guest explores, through research spanning string theory, gauge theory, Seiberg–Witten theory, matrix models, quantum curves, knot theory, and even biophysics through the topology of biomolecules. We’re thrilled to welcome Professor Piotr Sułkowski, a theoretical physicist at the University of Warsaw and a visiting faculty member at Caltech. He leads the Chair of Quantum Mathematical Physics, and his work explores some of the most elegant and fundamental structures in modern physics. Alongside that, he has also been actively involved in making science accessible to broader audiences through outreach projects like “Ask a Physicist.” Professor Sułkowski, it’s such a pleasure to have you with us today. Important links: Piotr's Website: https://psulkows.fuw.edu.pl/

    42 min
  3. FEB 28

    Niko Šarčević on Modern Cosmology

    Most of what we know about the universe actually comes from what we can’t see. Only a tiny fraction of the cosmos is made of “normal” matter—the stuff that makes up stars, planets, and us. The rest is a mysterious combination we call dark matter and dark energy, which, although invisible to our telescopes, is absolutely crucial for how the universe expands and how structures form over billions of years. So how do we even study something we cannot see? One of the most powerful tools we have is weak gravitational lensing. As light from distant galaxies travels through the cosmic web, the gravity of dark matter gently stretches and shears those galaxy images. The effect on any single galaxy is tiny, almost imperceptible. But when you measure this across millions or even billions of galaxies, a pattern emerges—a subtle cosmic fingerprint that tells us how matter is distributed and how fast the universe is expanding. This is what our guest today, Dr. Nikolina Sarcevic, works on. She is a cosmologist working at the intersection of data and theory. Nikolina is part of the LSST Dark Energy Science Collaboration, and her work focuses on understanding and modelling the systematics that can bias our measurements—things like how galaxies are intrinsically aligned, how we infer their redshift distributions, and how all of that feeds into weak lensing and dark energy constraints. So if you’ve ever wondered how we really know that dark energy exists, or what kinds of experiments are used to learn about this invisible matter, you’re going to be thrilled. So with that, let’s go.

    1h 39m
  4. 10/26/2025

    Daniel Whiteson on Do Aliens Speak Physics?

    Imagine: it’s a lazy Sunday morning, you’re sipping your raspberry-flavored iced latte, and an interstellar traveler lands in your backyard. It starts walking toward you—what do you do? Are you terrified or calm? If you’re a scientist stuck on a problem for years, do you ask for help? If you’re an influencer, are you already crafting your next post? If you’re a cook, are you hunting for new recipes? Honestly, with our limited human experience and understanding, it’s hard to even imagine such an encounter. To help us out, today’s podcast guest, Daniel Whiteson—along with Andy Warner—has written an incredible book illustrating exactly this scenario. Daniel is an experimental particle physicist and a professor of physics and astronomy at the University of California, Irvine. Anchored by his deep knowledge, Daniel asks in the book: can aliens speak physics? The book hits shelves on November 4, and we got to check out a pre-release copy. In today’s episode, we talk with Daniel about his mindset, the fundamentals and nuances of this alien encounter, and how we might communicate with them—without giving away any spoilers. Also, every new episode comes with its own lessons and the lesson her was to make multiple backups of your files because our SSD got corrupted and while we could recover our video files we couldn't recover the audio files. So the audio you're listening to is the one that got recorded by out camera. So anyway whether you’re dying to meet the green dudes, swear you’ve already seen them, or you’re simply curious about what such questions reveal about us humans, you’re in for a delight. So, let’s go! Daniel Ofir Whiteson is an American experimental particle physicist at University of California, Irvine. https://sites.uci.edu/daniel/ He is a co-creator of Elinor Wonders Why, an animated educational television show on PBS Kids. He co-hosts a podcast with biologist Kelly Weinersmith titled Daniel and Kelly's Extraordinary Universe. https://podcasts.apple.com/us/podcast/daniel-and-kellys-extraordinary-universe/id1436616330 Check out his new book: “Do Aliens Speak Physics (http://www.alienspeakphysics.com/)” which explores what it might be like to try to talk to advanced aliens about physics. Will they do physics the way we do, or is our most basic science more human than Universal?

    1h 8m
  5. 09/29/2025

    Eve M. Vavagiakis on What goes into Cosmological Observations

    The universe is about 14 billion years old. Ever wondered—how do we even know the age of the universe? How can we look up at the sky and read time itself? We do this by studying the afterglow of the Big Bang, called the cosmic microwave background radiation (CMBR)—relic radiation from the very beginning of the universe. Physicists build ultra-cold microwave telescopes—cryogenic cameras with incredibly sensitive detectors—that can spot tiny temperature changes and faint polarization, and even see how gravity bends that light. In this episode, Dr. Eve Vavagiakis, an experimental cosmologist at Duke University, takes us behind the scenes of how these instruments are designed, built, and calibrated across ACT, the Simons Observatory, CCAT-prime, and CMB-S4. Her expertise spans cryogenic instrumentation, superconducting detectors, and extracting meaningful physics from enormous datasets. She also writes children’s science books that turn big cosmic ideas into playful stories for young readers—bringing neutrinos, black holes, and photons to life. She believes kids should have access to—even if not a complete understanding of—the latest discoveries and complex ideas. If you wonder how we know the universe’s age—or you just like telescopes—you’re in for a delight. About the guest Dr. Eve Vavagiakis is an Assistant Professor of Physics at Duke University. She builds instruments and analyzes data for cosmology and astrophysics, and works with the ACT, CCAT-prime, Simons Observatory, and CMB-S4 collaborations. Her interests include cryogenic instrumentation, superconducting detectors, and cross-correlation studies that reveal the physics of galaxy clusters and the universe. Previously an NSF Astronomy & Astrophysics Postdoctoral Fellow at Cornell, she’s also the author of the Meet the Universe children’s book series from MIT Kids Press. Students excited about instrumentation or data analysis are welcome to reach out. Website: https://evevavagiakis.com

    1h 13m
  6. 08/23/2025

    Ramakrishna V. Hosur on when Science Meets Spirituality

    Science and philosophy have always been woven together. Some of history’s greatest minds—Aristotle, Galileo, Aryabhata and even Einstein—were as much philosophers as they were scientists. This has also been true for ancient Indian civilization, where science and philosophy were explored with extraordinary depth, not as separate pursuits, but as complementary paths to knowledge.  These insights were preserved in Sanskrit, a language whose precision allowed complex ideas to be recorded with remarkable clarity. But centuries of invasions and nearly a thousand years of foreign rule made this knowledge less accessible, and its nuance steadily eroded.  Much of it was collapsed into the broad label of “spirituality”—a word that has itself lost the rigor and depth it once carried. The central dogma of these ancient Indian texts was an uncompromising commitment to curiosity and questioning.  Our guest today, Dr. Ramakrishnan Hosur, apart from being a renowned figure in science, has embarked on the journey of demystifying these texts with that same uncompromising commitment. He believes in building upon that curiosity and using it as an anchor for scientific progress. In his book, Where Science Meets Spirituality, he explores precisely this intersection.  Dr. Hosur is a distinguished biophysicist and his remarkable career spans pioneering developments in nuclear magnetic resonance (NMR) spectroscopy, structural biology, and protein folding. His work earned him India’s fourth-highest civilian honour, the Padma Shri, in 2014. He has spent decades at the Tata Institute of Fundamental Research in Mumbai, where he also headed the National Facility for High-Field NMR. And now, he has been inspiring a whole new way of looking at knowledge by demystifying ancient Indian texts and showing how curiosity can bridge science and spirituality.  So if you’re someone who finds inspiration at the crossroads of science, philosophy and spirituality, or simply someone who’s just curious, you’re in for a treat. So let's go. His wikipedia page: https://en.wikipedia.org/wiki/Ramakrishna_V._Hosur

    1h 43m
  7. 07/18/2025

    Pavan Hosur on Eigenstate Thermalization Hypothesis

    Imagine walking deep into a dense forest without a map or GPS. Initially, you kind of know where you started. But as you wander further, eventually, it's impossible to tell where you came from — every direction looks the same. That's thermalization.  The initial state's details get scrambled across all degrees of freedom and as a result local observables settle into a stable, time-independent state called the equilibrium state. The fact that macroscopic objects equilibrate with their environments is such a ubiquitous experience that understanding it doesn't seem very interesting. Although it's absolutely non-trivial. At Equilibrium these local observables are represented by their thermal expectation values.  So if one had access to a map or perhaps a GPS which just means keeping track of those initial details such as any non-local correlations or even the entire state, locally thermalization would still occur, but one could easily backtrack to the initial state. In physics it is quite surprising how systems behave collectively, when compared to the behavior of its components. This is known as emergent behavior.  We've been taught that evolution of any system should entirely depend on initial conditions but we see that a lack of initial state dependence is what actually gives a consistent behavior macroscopically.  For an isolated quantum many-body system, this becomes even more fascinating because even though the full evolution, is unitary and reversible--which means backtracking is guaranteed-- locally, memory seems to be lost.  Then how does this classical behaviour emerge from Quantum mechanics?  A key idea is the Eigenstate Thermalization Hypothesis (ETH): each non-degenerate energy eigenstate itself can be considered “thermal”. Their expectation values fluctuate little between nearby eigenstates, provided the local operator acts on few degrees of freedom.   Intuitively, a small subsystem of an isolated quantum system acts as if it's in contact with a thermal bath—the rest of the system. So in large, non-integrable systems, thermal behavior emerges without needing a microcanonical average—a single eigenstate often suffices.  If ETH is true then if the initial state dependent coefficients are concentrated around some single energy then our TEV will give the desired microcanonical and canonical averages.  Our guest today is Pavan Hosur, a theoretical physicist in the Department of Physics and the Texas Center for Superconductivity at the University of Houston. His research focuses on understanding topological phases of matter, exotic broken symmetry phases, and how to detect them experimentally. He also explores quantum ergodicity, quantum chaos, and more broadly, how concepts from classical statistical mechanics extend into the quantum realm. We’re recording this episode in his lovely office, discussing how our complex yet elegant macroscopic world emerges from the quantum laws that govern the microscopic one. So let’s get started. His website is here: https://sites.google.com/nsm.uh.edu/qmb/home

    1h 25m

Ratings & Reviews

5
out of 5
4 Ratings

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This podcast is about Science, Technology, Engineering, Mathematics, Music, Philosophy, Culture, Graduate life and much more.