Conference

Displaying 313 - 324 of 4904

Holographic Thermodynamics: C-ing a Black Hole

Ruth Gregory
King's College London
October 26, 2023

PIRSA:23100010
Quantum Gravity
Hearts of Darkness: Nonsingular Black Holes Beyond General Relativity

Francesco Di Filippo
Kyoto University
October 26, 2023

PIRSA:23100013
Quantum Gravity
Quantum hair and information loss paradox - VIRTUAL

Xavier Calmet
University of Sussex
October 26, 2023

PIRSA:23100067
Quantum Gravity
Open Discussion with today's speakers (Ashtekar, Surya, Vieira)
- Abhay Ashtekar
  Pennsylvania State University
- Sumati Surya
  Raman Research Institute
- Pedro Vieira
  Perimeter Institute for Theoretical Physics
October 25, 2023

PIRSA:23100012
Quantum Gravity
Panel Discussion - Cosmological Puzzles (Ashtekar, Brandenberger, Geshnizjani, Sakellariadou, Yazdi)
- Abhay Ashtekar
  Pennsylvania State University
- Robert Brandenberger
  McGill University - Department of Physics
- Ghazal Geshnizjani
  Perimeter Institute for Theoretical Physics
- Mairi Sakellariadou
  King's College London
- Yasaman Kouchekzadeh Yazdi
  Dublin Institute For Advanced Studies
October 25, 2023

PIRSA:23100011
Quantum Gravity
Where is String Theory

Pedro Vieira
Perimeter Institute for Theoretical Physics
October 25, 2023

PIRSA:23100066
Quantum Gravity
Puzzles, Resolutions and Open Questions in Causal Set Theory - VIRTUAL

Sumati Surya
Raman Research Institute

October 25, 2023

PIRSA:23100065
Glimpses into Loop Quantum Gravity

Abhay Ashtekar
Pennsylvania State University
October 25, 2023

PIRSA:23100009
Quantum Gravity
Panel Discussion - QFT vs beyond-QFT approaches (Buoninfante, Rejzner, Smolin, Vieira)
- Luca Buoninfante
  Nordic Institute for Theoretical Physics
- Benjamin Knorr
  Nordic Institute for Theoretical Physics
- Katarzyna Rejzner
  University of York
- Lee Smolin
  Perimeter Institute for Theoretical Physics
- Pedro Vieira
  Perimeter Institute for Theoretical Physics
October 24, 2023

PIRSA:23100008
Quantum Gravity
Open Discussion with today's speakers (Buoninfante, Eichhorn, Holdom, Knorr, Loll)
- Luca Buoninfante
  Nordic Institute for Theoretical Physics
- Astrid Eichhorn
  University of Southern Denmark
- Bob Holdom
  University of Toronto
- Benjamin Knorr
  Nordic Institute for Theoretical Physics
- Renate Loll
  Radboud Universiteit Nijmegen
October 24, 2023

PIRSA:23100007
Quantum Gravity
Form Factors - a unifying language for Quantum Gravity

Benjamin Knorr
Nordic Institute for Theoretical Physics
October 24, 2023

PIRSA:23100087
Quantum Gravity
The Case for Renormalizable Quantum Gravity: from local to nonlocal approaches (and back!)

Luca Buoninfante
Nordic Institute for Theoretical Physics
October 24, 2023

PIRSA:23100064
Quantum Gravity

Holographic Thermodynamics: C-ing a Black Hole

Ruth Gregory
King's College London
October 26, 2023

PIRSA:23100010
Quantum Gravity
One of the fascinating things about Black Hole Thermodynamics is how we often approach it in a very classical fashion, yet - if real - it is an intrinsically quantum phenomenon. I'll use the illustration of thermodynamics of an accelerating black hole to highlight some of these issues, and I'd like to raise questions on how we derive the First Law, and how unique this derivation is.
Hearts of Darkness: Nonsingular Black Holes Beyond General Relativity

Francesco Di Filippo
Kyoto University
October 26, 2023

PIRSA:23100013
Quantum Gravity
Black holes contain, deep in their interior, theoretical evidence of the failure of general relativity. A series of fundamental results, starting from the 1965 Penrose singularity theorem, proved that physically realistic initial conditions will unavoidably produce a singular black hole spacetime. It is generally expected that a full theory of quantum gravity should remove the singularities that appear in general relativity. However, the lack of proper understanding of the dynamical laws dictating the evolution of spacetime and matter in these extreme situations hinders the extraction of predictions in specific models. I will discuss, in a model-independent manner, the different possibilities that singularity regularization may open. I will then focus on fundamental open issues that need to be addressed to obtain viable nonsingular black hole candidates.
Quantum hair and information loss paradox - VIRTUAL

Xavier Calmet
University of Sussex
October 26, 2023

PIRSA:23100067
Quantum Gravity
In this talk I present our solution to the information paradox published in Phys.Rev.Lett. 128 (2022) 11, 111301 and Phys.Lett.B 827 (2022) 136995 (see EPL 139 (2022) 4, 49001 for a review). Long wavelength quantum gravitational effects allow the interior state of the black hole to influence Hawking radiation, leading to unitary evaporation. I explain why the Mathur theorem is evaded due to the complex nature of the Hawking radiation superposition state. --- The presenter will be joining via Zoom for this talk.
Open Discussion with today's speakers (Ashtekar, Surya, Vieira)
- Abhay Ashtekar
  Pennsylvania State University
- Sumati Surya
  Raman Research Institute
- Pedro Vieira
  Perimeter Institute for Theoretical Physics
October 25, 2023

PIRSA:23100012
Quantum Gravity
Panel Discussion - Cosmological Puzzles (Ashtekar, Brandenberger, Geshnizjani, Sakellariadou, Yazdi)
- Abhay Ashtekar
  Pennsylvania State University
- Robert Brandenberger
  McGill University - Department of Physics
- Ghazal Geshnizjani
  Perimeter Institute for Theoretical Physics
- Mairi Sakellariadou
  King's College London
- Yasaman Kouchekzadeh Yazdi
  Dublin Institute For Advanced Studies
October 25, 2023

PIRSA:23100011
Quantum Gravity
Where is String Theory

Pedro Vieira
Perimeter Institute for Theoretical Physics
October 25, 2023

PIRSA:23100066
Quantum Gravity
Puzzles, Resolutions and Open Questions in Causal Set Theory - VIRTUAL

Sumati Surya
Raman Research Institute

October 25, 2023

PIRSA:23100065

I will begin with a broad overview of the main ingredients of causal set theory, and then discuss the partial resolution of a long-standing "puzzle" in the causal set path sum. I will then discuss other causal set curiousities, ending with a brief overview of the challenges in constructing a realistic fully non-perturbative quantum dynamics. --- The presenter will be joining via Zoom for this talk.
Glimpses into Loop Quantum Gravity

Abhay Ashtekar
Pennsylvania State University
October 25, 2023

PIRSA:23100009
Quantum Gravity
The organizers requested an overview of Loop Quantum Gravity (LQG). However, this is an impossible task, especially for a 30 minute talk, given that the subject is over three decades old with tens of thousands of papers. Instead, I will outline some of the key distinguishing features of LQG and discuss an illustrative application. Hopefully these topics will complement those that will be covered by Bianca Dittrich and Lee Smolin, without too much of an overlap.
Panel Discussion - QFT vs beyond-QFT approaches (Buoninfante, Rejzner, Smolin, Vieira)
- Luca Buoninfante
  Nordic Institute for Theoretical Physics
- Benjamin Knorr
  Nordic Institute for Theoretical Physics
- Katarzyna Rejzner
  University of York
- Lee Smolin
  Perimeter Institute for Theoretical Physics
- Pedro Vieira
  Perimeter Institute for Theoretical Physics
October 24, 2023

PIRSA:23100008
Quantum Gravity
Open Discussion with today's speakers (Buoninfante, Eichhorn, Holdom, Knorr, Loll)
- Luca Buoninfante
  Nordic Institute for Theoretical Physics
- Astrid Eichhorn
  University of Southern Denmark
- Bob Holdom
  University of Toronto
- Benjamin Knorr
  Nordic Institute for Theoretical Physics
- Renate Loll
  Radboud Universiteit Nijmegen
October 24, 2023

PIRSA:23100007
Quantum Gravity
Form Factors - a unifying language for Quantum Gravity

Benjamin Knorr
Nordic Institute for Theoretical Physics
October 24, 2023

PIRSA:23100087
Quantum Gravity
QFT's remarkable success lies in its ability to yield precise predictions through e.g. scattering amplitudes, capturing the essence of running couplings in a gauge-invariant manner. However, the introduction of gravity disrupts this straightforward notion of momentum dependence, posing a significant challenge to our theoretical framework. Enter form factors—an ingenious concept that extends the idea of momentum dependence to the curved spacetime of quantum gravity. They form the central ingredient when discussing quantum gravity in a QFT language. Furthermore, within an effective action, form factors offer a unifying language, allowing us to compare and contrast different quantum gravity approaches apples-to-apples. I will give an overview of the ideas underlying form factors, their application to scattering problems, and their potential to put different approaches on the same footing.
The Case for Renormalizable Quantum Gravity: from local to nonlocal approaches (and back!)

Luca Buoninfante
Nordic Institute for Theoretical Physics
October 24, 2023

PIRSA:23100064
Quantum Gravity
In the context of perturbative quantum field theory (QFT), the addition of quadratic-curvature invariants to the Einstein-Hilbert action makes it possible to achieve strict renormalizability in four dimensions. This theory exhibits unusual features due to an additional massive spin-2 ghost which, in general, may cause instabilities. In the first part of this talk, we focus on the possibility of giving up locality as a way to avoid ghost-like degrees of freedom and provide a critical assessment on open questions in nonlocal theories of gravity, such as the uniqueness problem. In the second part of the talk, we take a step back and argue that, despite the presence of the ghost and actually thanks to it, Quadratic Gravity can still provide a consistent local perturbative QFT description of the gravitational interaction and explain new physics beyond Einstein's general relativity, e.g., it offers a natural explanation for the inflationary phase. Finally, we argue that a type of nonlocality in gravity can still occur non-perturbatively and show that a new lower bound on scattering amplitudes indicates that the gravitational interaction is intrinsically nonlocal if black holes form.

Title	Speaker(s)	Date	Talk Type	Info link
Holographic Thermodynamics: C-ing a Black Hole	Ruth Gregory	2023-10-26	Conference	View details
Hearts of Darkness: Nonsingular Black Holes Beyond General Relativity	Francesco Di Filippo	2023-10-26	Conference	View details
Quantum hair and information loss paradox - VIRTUAL	Xavier Calmet	2023-10-26	Conference	View details
Open Discussion with today's speakers (Ashtekar, Surya, Vieira)	Abhay Ashtekar, Sumati Surya, Pedro Vieira	2023-10-25	Conference	View details
Panel Discussion - Cosmological Puzzles (Ashtekar, Brandenberger, Geshnizjani, Sakellariadou, Yazdi)	Abhay Ashtekar, Robert Brandenberger, Ghazal Geshnizjani, Mairi Sakellariadou, Yasaman Kouchekzadeh Yazdi	2023-10-25	Conference	View details
Where is String Theory	Pedro Vieira	2023-10-25	Conference	View details
Puzzles, Resolutions and Open Questions in Causal Set Theory - VIRTUAL	Sumati Surya	2023-10-25	Conference	View details
Glimpses into Loop Quantum Gravity	Abhay Ashtekar	2023-10-25	Conference	View details
Panel Discussion - QFT vs beyond-QFT approaches (Buoninfante, Rejzner, Smolin, Vieira)	Luca Buoninfante, Benjamin Knorr, Katarzyna Rejzner, Lee Smolin, Pedro Vieira	2023-10-24	Conference	View details
Open Discussion with today's speakers (Buoninfante, Eichhorn, Holdom, Knorr, Loll)	Luca Buoninfante, Astrid Eichhorn, Bob Holdom, Benjamin Knorr, Renate Loll	2023-10-24	Conference	View details
Form Factors - a unifying language for Quantum Gravity	Benjamin Knorr	2023-10-24	Conference	View details
The Case for Renormalizable Quantum Gravity: from local to nonlocal approaches (and back!)	Luca Buoninfante	2023-10-24	Conference	View details

Format results