Quantum Gravity at the Big Bang and on a Table Top
18 September - 18 December 2022
Biography
Nick Huggett is an LAS Distinguished Professor at the University of Illinois Chicago, whose work lies in the philosophy of science and the philosophy of physics. He earned his PhD from Rutgers University in 1995, for a dissertation on philosophical questions in quantum field theory. This work formed the basis for his early work, for example The Renormalization Group and Effective Field Theories (with Robert Weingard, in Synthese, 1995). Later work concerned theories of space from antiquity to the present: e.g., Space from Zeno to Einstein (MIT Press, 1999) and The Regularity Account of Relational Spacetime (Mind, 2006). He has also published in the foundations of quantum mechanics, including collaborations with Tom Imbo (UIC Physics): here his work focusses on the nature of identical particles. Many of the ideas from all this work were presented for a general audience in Everywhere and Everywhen (OUP, 2010).
Over the past decade, Huggett’s work has focussed on the philosophical implications of quantum gravity, and especially the possibility that space and time may not be fundamental, given ingredients of the world, but ‘emerge’ from something even more basic. In this work he has formed a collaboration with Christian Wüthrich (University of Geneva), for which they have received funding from ACLS, NSF, SNSF, the John Templeton Foundation, FQXi, and others. He has co-edited three volumes on this topic, and been on author on numerous papers: for instance, Emergent Spacetime and Empirical (In)coherence (with Wüthrich, Studies in History and Philosophy of Modern Physics, 2013). Their Beyond Spacetime project (www.beyondspacetime.net) has organized workshops, speaker series, and summer schools, and supports dialogue between philosophers and physicists on these topics.
Research summary
The nature of space and time is a perennial issue of philosophy, from the presocratics, though Newton and Einstein, to the present, engaging at the deepest level with mathematics, psychology and physics. However, philosophy has only recently begun to consider the most recent developments in spacetime physics: theories of 'quantum gravity' (QG), such as string theory. These theories are not fully developed, but they raise many deep philosophical challenges: one strong suggestion is that space and time are not fundamental ingredients of the world, but somehow arise – or 'emerge' – from a deeper reality that does not contain them. This idea that the universe might not, at bottom, be 'in' space and time, that these seemingly fundamental ingredients are just the appearances of something more fundamental, would shatter our conception of the universe as profoundly as any previous revolution. However, it is very hard to test QG empirically, because most of its characteristic effects are thought to occur at extreme energies, such as those found at the big bang.
During his tenure at Bristol as a Benjamin Meaker Distinguished Visiting Professor, Huggett will primarily collaborate with the philosopher, Professor James Ladyman on conceptual issues relating to recent proposals to observe the quantum nature of gravity in a way not previously considered, and perhaps possible in laboratory experiments. Such experiments will require masses tiny enough that quantum effects occur, but heavy enough that gravitational forces are significant: an extremely challenging proposition – though by far our best hope of experiments in QG. But there are subtle questions about the interpretation of the experiment, and in particular whether the predicted effect genuinely involves quantum gravity at all, depending on philosophical issues in quantum mechanics, gravity, and their intersection. Since this work draws on ideas in quantum information theory, Huggett will also be engaging with the Physics Department’s Quantum Information Institute, as well as other members of the philosophy department.
Professor Huggett is hosted by Professor James Ladyman, Philosophy.
Planned activity includes:
Tuesday 7 December, 5 - 7 pm
Open Lecture, Mott Lecutre Theatre, Physics
Explaining Spacetime
Professor Huggett will explain the idea that space and time might be ‘emergent’ from a non-spatiotemporal physics. He will describe examples from string theory and non-commutative geometry to argue that ‘position’ is not fundamental, and how it can be derived. He will use this discussion to explain how evidence of experiments in space might lead us to doubt whether space is a fundamental ingredient of the physical world.
Departmental seminar for philosophers and physicists
Big Bang in Quantum Gravity
Postgraduate seminar
Emergence of Spacetime in String Theory
