Wallace to speak at UIC

On Wednesday 18 October 2017 please join us at UIC (or at Geneva via livestream, or on our YouTube channel) to hear David Wallace (USC) speaking on “The Case for Black Hole Thermodynamics”

Abstract: I give a fairly systematic and thorough presentation of the case for regarding black holes as thermodynamic systems in the fullest sense (contra recent work by Dougherty and Callender), with particular attention to (i) the availability in classical black hole thermodynamics of a well-defined notion of adiabatic intervention; (ii) the power of the membrane paradigm to make black hole thermodynamics precise and to extend it to local-equilibrium contexts; (iii) the central role of Hawking radiation in permitting black holes to be in thermal contact with one another; (iv) the wide range of routes by which Hawking radiation can be derived and its back-reaction on the black hole calculated; (v) the interpretation of Hawking radiation close to the black hole as a gravitationally bound thermal atmosphere.

More information on all talks above.


First talk of the year!

• Wednesday 27 September 2017 at Geneva – Alexei Grinbaum (CEA-Saclay/LARSIM): How device-independent approaches change the meaning of physical theory

Abstract: Dirac sought an interpretation of mathematical formalism in terms of physical entities and Einstein insisted that physics should describe “the real states of the real systems”. While Bell inequalities put into question the reality of states, modern device-independent approaches do away with the idea of entities: physical theory may contain no physical systems. Focusing on the correlations between operationally defined inputs and outputs, device-independent methods promote a view more distant from the conventional one than Einstein’s `principle theories’ were from `constructive theories’. On the examples of indefinite causal orders and almost quantum correlations, we ask a puzzling question: if physical theory is not about systems, then what is it about? Device-independent models suggest that physical theory can be `about’ languages. This answer indicates a direction for moving beyond quantum theory. In terms of technical difficulty, this talk rates 4/5 4


Please visit us next year!

We invite interested scholars for short visits to the Spacetime After Quantum Gravity research group, located in the philosophy departments at the University of Illinois at Chicago and the University of Geneva. To facilitate visits we can offer financial assistance for travel and lodging, office facilities, and of course excellent intellectual company. Visits can be from a few days to a few weeks (or possibly longer).

Details are here: https://beyondspacetime.net/space-and-time-after-quantum-gravity/visit-us/

Last Talk of the Year!

Please join us this week for the final talk of the year – in Chicago at 11am in UH1430, on skype in Geneva, or on YouTube.

• Wednesday 31 May 2017 at UIC – Nic Teh (Notre Dame): Newton-Cartan theory and Emergent Newtonian Gravitation

Abstract: In recent work on the philosophy of Newtonian gravitation, there has been much discussion of whether the theory’s “spacetime geometry” is best conceived of as Newton-Cartan geometry, on the one hand, or Maxwellian geometry, on the other hand. Roughly speaking, there have been two approaches to understanding this question: one starts from the idea of “relations between observers”, and the other begins from the standard differential geometric architecture of Newton-Cartan theory and the Trautman Recovery Theorem. In this talk, I will explain how the two approaches can be reconciled, thereby yielding “emergent Newtonian gravitation” as a gauge-fixing of Newton-Cartan theory. In terms of technical difficulty, this talk rates 4/5 4

Talk this week!

• Wednesday 24 May 2017 at Geneva – Samuel Fletcher (Minnesota): Reduction, emergence, and direct limits

Abstract: Most discussions of spacetime emergence and the “physical salience” of the structures employed in theories of quantum gravity have understood these terms informally. Applying some new formal definitions based on “similarity structure” on models of theories, I show how to make more precise the sense in which a physical continuum of events could be emergent, and to connect the discussion of physical salience with a precise definition of intertheoretic reduction. As a test example, I consider claims about the emergence of the continuum of relativistic spacetime from direct limits of causal set histories, showing how their justification, though presently incomplete, could be completed. Time permitting, I will comment on the relation between this approach and causal set theory’s hauptvermutung. In terms of technical difficulty, this talk rates 4/5 4

See above links for details.