First Talk by a Prize Winner – Henrique Gomes

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One of the winners of our essay prize, Henrique Gomes (Perimeter Institute) will speak on Wednesday May 25th 2016 at UIC. His title is Timeless Quantum Mechanics in Configuration Space

Abstract: “In this talk, I will argue in favor of a  ‘transition amplitude’ approach to quantum gravity. For such a position to be internally consistent, not all types of symmetries are allowed. I will describe which ones are and we will see how refoliations become problematic – I will contend that they should only be recovered dynamically (as an on-shell, or effective, symmetry). Given this ‘transition amplitude’  point of view, I will further elaborate on how the allowed symmetries select a unique ‘in state’  for the amplitude. We can thereby use this ‘in state’ to produce a static wavefunction of the Universe, much like some of the interpretations of the Wheeler-DeWitt. Lastly, I will describe how one can extract our usual notion of time from such a fundamentally timeless view, at least semi-classically, through a structure called ‘semi-classical records’. Time allowing (no pun intended), I will further speculate on some recent progress in a relation between renormalization group flow and a notion of instantaneous duration (this part will be pure speculation).”
Please join us at UIC, or Geneva, or on YouTube.

Francesca Vidotto this week

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Wednesday May 11th 2016 at Geneva – Francesca Vidotto (Radboud University Nijmegen): How classical spacetime emerges in Loop Quantum Gravity

Abstract: “Is space an entity or a net of relations? Is classical spacetime emergent? If it is emergent, what is it emerging from? Is spacetime fundamentally discrete or continuous? Is time an ingredient of the fundamental equations of the world? Is time flowing? These philosophical questions need to find an answer in a concrete realisation of a quantum theory of gravity. I illustrate the basics of Loop Quantum Gravity and the specific answers that each of these (philosophical) questions finds in the context of this (physical) theory. I focus on the notion of spacetime emergence: I argue that classical spacetime emerges from the quanta of spacetime, no differently from the emergence of electromagnetism having photons. This quantum emergence is studied in Loop Quantum Gravity, where there is a notion of classical limit. This limit should not be confused with a thermodynamical limit, that may exist but it is not necessary to recover classical spacetime. These ideas can be illustrated in analogy with the case of electromagnetism.” In terms of technical difficulty, this talk rates 4/5  4

Upcoming Talks

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Here are the talks in the next few weeks:

• Wednesday May 11th 2016 at Geneva – Francesca Vidotto (Nijmegen): TBA

• Wednesday May 25th 2016 at UIC – Henrique Gomes (Perimeter Institute): TBA

• Friday June 17th 2016 at UIC – DOUBLE HEADER!

Radin Dardashti (Munich Center for Mathematical Philosophy, and Geneva): TBA

Juliusz Doboszewski (Jagiellonian University, and Geneva): TBA

More information on the Speakers page above.

Crowther to talk at UIC this week

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• Wednesday April 27th 2016 at UIC – Karen Crowther: The Correspondence Principle in Quantum Gravity

Abstract: “The difficulties in discovering a theory of quantum gravity are due not only to its apparently extreme experimental inaccessibility, but the fact that there are no commonly accepted, formally established constraints that define its basic structure and objectives. I critically examine the role of the correspondence principle in quantum gravity, to evaluate its prospects as such a constraint. I find that there is a form of correspondence that serves as an essential heuristic guide in developing the theory, but that another form of correspondence has acquired a status of undue weight. It seems that the stress on deriving general relativity in the low-energy regime is unwise at this stage of theory-development, and possibly altogether.”  In terms of technical difficulty, this talk rates 3/5  3

Livestreaming planned

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We plan to live stream all of the talks this week on our YouTube channel (https://www.youtube.com/channel/UC_VhTJBl6Mpmfjj5q832rjg) — as we think we have solved the tech problems. In the menu of options, select ‘live streams’ at around 16:15 Swiss time tomorrow, and you should see it.

Double Header on Thursday April 14

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Two short talks, from both sides of the Atlantic:

(1) In Geneva, Giuliano Torrengo (Milan): The experience of the passage of time

(2) In Chicago, James Read (Oxford): Background Independence and Holography

For more information follow the links above.

Essay Contest 2016

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We are thrilled to announce the winners of our first essay prize!

In alphabetical order:
“Back to Parmenides” Henrique Gomes (Perimeter Institute)
“Taking Up Superspace” Tushar Menon (Oxford)
“What can (mathematical) categories tell us about space time?” Ko Sanders (Leipzig)

Congratulations to them, and commiserations to the authors of the many other excellent papers that were submitted. Thanks to them all for their patience with the judging process. Even bigger thanks to the referees, who worked very hard.

Look for talks by the winners in the next few months, and for their papers online (TBA) and ultimately in edited volumes we are planning on the philosophy and foundations of quantum gravity.