Quantum Foundations Podcast

Gerard Milburn, a theoretical physicist specializing in quantum optics and foundations, proposes radical ideas at the quantum–gravity interface. He explores whether unmeasured pure quantum states fail to source gravity. Topics include Bell tests and spacetime labeling, gravity’s role in assigning coordinates, implications for black holes and the Big Bang, and possible limits on large-scale quantum technologies.

Tony Short, a theoretical physicist at the University of Bristol who studies quantum foundations, explains why a universal Schrödinger evolution leads to branching worlds. He outlines three simple assumptions that connect branching, decoherence and conserved weights to derive Born-rule probabilities. Short also discusses swap arguments, technical extensions for irrational amplitudes, and how these ideas fit into broader foundations research.

Tim Palmer, Royal Society Research Professor at Oxford known for chaos theory and climate physics, proposes a fractal, discrete rethink of quantum theory. He links chaos and Cantor-like geometry to challenge counterfactual assumptions. He explains how fractal state spaces and rationalized Hilbert coefficients could block Bell-style nonlocality and suggests a gravity-linked limit to quantum advantage.

Dr. Will Zeng, founder of the Unitary Foundation, dives into the intriguing world of quantum observers. He explores how placing an observer in superposition could reshape our understanding of reality. Zeng discusses the measurement problem, local agency, and the implications of violating local friendliness inequalities. He shares insights from recent experiments using photonic qubits, and outlines a roadmap for testing increasingly realistic observers, including the potential for quantum Artificial General Intelligence. This episode is a thrilling journey into the heart of quantum mechanics!

Dr. Chiara Marletto, a research fellow at Oxford, delves into the fascinating world of conservation laws in physics. She discusses how these laws have historically spurred theoretical breakthroughs and their critical role in thermodynamics. Marletto contrasts conservation principles with dynamics, emphasizing their utility in reasoning about future physics theories. She explores the implications in quantum mechanics and proposes novel experimental designs based on these principles, linking them to programmability in thermodynamics and the limits of quantum computing.

In this discussion, Matthew Gray, an Oxford Computer Science PhD student, explores the intriguing intersection of quantum computing and cryptography. He unpacks quantum post-quantum cryptography, revealing how layers of complexity can be navigated. The conversation delves into the dangers posed by quantum adversaries to classical systems and highlights innovative crypto proposals like isogeny-based schemes. Matthew also discusses fundamental concepts of metacomplexity and what potential new physics might imply for computing and security. Prepare for a mind-bending journey!

Dr. Simone Rijavec, a postdoctoral researcher at Tel Aviv University and former Oxford scholar, dives into the mind-bending concept that time may not be fundamental but rather an emergence from quantum mechanics. She discusses the intriguing Wheeler–DeWitt equation and the Page–Wootters model of relational time, explaining how our perception of time may come from superpositions of quantum states. Additionally, she explores the idea of distinct experiences existing as real branches in a multiverse and emphasizes the operational nature of time through quantum clocks.

In this discussion, physicist Dr. Aditya Iyer from the University of Oxford delves into the fascinating interplay between quantum phenomena and cosmology. He examines how the early universe, just moments after the Big Bang, was potentially quantum entangled. Dr. Iyer sheds light on cosmic inflation and its implications for structure formation. He also addresses the challenges posed by non-local phenomena and the significance of quantum fluctuations in shaping our universe, offering insights into the fundamental nature of reality itself.

In this fascinating discussion, Dr. Chiara Marletto, a Research Fellow at the University of Oxford, delves into Constructor Theory of information. She explores how this innovative framework might redefine our understanding of both classical and quantum information, bridging gaps in modern physics. Marletto discusses the interplay of determinism and stochasticity within quantum systems, and highlights a compelling theorem linking quantum entanglement with gravity, urging a fresh look at foundational physics. This talk is a captivating journey into the future directions of quantum theory!

Professor Vlatko Vedral, a leading quantum physics expert from the University of Oxford, dives into the intricate relationship between quantum mechanics and gravity. He explores historic and modern proposals for testing quantum gravity and the significant challenges faced in reconciling it with general relativity. The discussion takes a fascinating turn as they discuss the black hole information paradox and experimental advancements involving nanodiamonds. Tune in to learn how these concepts could reshape our understanding of the universe!