Le contenu de cette page n’est pas disponible en français. Veuillez nous en excuser.

Quantum Gravity

This series consists of talks in the area of Quantum Gravity.

Seminar Series Events/Videos

fév 25 2019 - 11:00am
Room #: 294
Speaker(s):
Scientific Areas:
fév 25 2019 - 1:30pm
Room #: 294
Speaker(s):
Scientific Areas:
fév 26 2019 - 11:00am
Room #: 294
Speaker(s):
Scientific Areas:
fév 26 2019 - 1:30pm
Room #: 294
Speaker(s):
Scientific Areas:
fév 27 2019 - 3:30pm
Room #: 301
Speaker(s):
Scientific Areas:
TBA
fév 28 2019 - 2:30pm
Room #: 400
Speaker(s):
Scientific Areas:
mar 7 2019 - 2:30pm
Room #: 400
Speaker(s):
Scientific Areas:
mar 11 2019 - 1:00pm
Room #: 400
Speaker(s):
Scientific Areas:
TBA
mar 14 2019 - 2:30pm
Room #: 400
Speaker(s):
Scientific Areas:
avr 19 2019 - 2:30pm
Room #: 400
Speaker(s):
Scientific Areas:
 

 

Jeudi jan 24, 2019
Speaker(s): 

Black hole entropy is a robust prediction of quantum gravity with no observational test to date. We use the Bekenstein-Hawking entropy formula to determine the probability distribution of the spin of black holes at equilibrium in the microcanonical ensemble. We argue that this ensemble is relevant for black holes formed in the early universe and predicts the existence of a population of black holes with zero spin.

Collection/Series: 
Scientific Areas: 
 

 

Jeudi jan 17, 2019
Speaker(s): 

I argue that we do not understand gauge theory as well as we think when boundaries are present. I will briefly explain the conceptual and technical issues that arise at the boundary.  I will then propose a tentative resolution, which requires us to think of theories not in spacetime, but in field-space. 

Collection/Series: 
Scientific Areas: 
 

 

Jeudi jan 10, 2019
Speaker(s): 

Black holes are like bells; once perturbed they will relax through the emission of characteristic waves. The frequency spectrum of these waves is independent of the initial perturbation and, hence, can be thought of as a `fingerprint' of the black hole. Since the 1970s scientists have considered the possibility of using these characteristic modes of oscillation to identify astrophysical black holes. With the recent detection of gravitational waves, this idea has started to turn into reality.

Collection/Series: 
Scientific Areas: 
 

 

Jeudi oct 25, 2018
Speaker(s): 

We  find an  approximation of  the induced spatial distance on a Cauchy hypersurface using only the causal structure and local volume element. The approximation can be made arbitrarily precise for a globally hyperbolic spacetime with compact Cauchy hypersurfaces.

Collection/Series: 
Scientific Areas: 
 

 

Jeudi oct 11, 2018
Speaker(s): 

I discuss the canonical degrees of freedom of metric Einstein gravity on a null surface. The constraints are interpreted as conservation equations of a boundary current. Gravitational fluxes are identified, and the Hamiltonians of diffeomorphism symmetry are discussed. Special attention is given to the role of a modification of the phase space at the boundary of the null surface. Based on 1802.06135 with Laurent Freidel.

Collection/Series: 
Scientific Areas: 
 

 

Jeudi oct 04, 2018
Speaker(s): 

The large j asymptotic behavior of 4-dimensional spin foam amplitude is investigated for the extended spin foam model (Conrady-Hnybida extension) on a simplicial complex. We study the most general situation in which timelike tetrahedra with timelike triangles are taken into account. The large j asymptotic behavior is determined by critical configurations of the amplitude. We identify the critical configurations that correspond to the Lorentzian simplicial geometries with timelike tetrahedra and triangles. Their contributions to the amplitude are phases asymptotically, whose exponents equal

Collection/Series: 
Scientific Areas: 
 

 

Jeudi sep 20, 2018
Speaker(s): 

I will discuss certain irrelevant operator deformations of holographic conformal field theories that define a one parameter family of quantum field theories which are thought to be dual to quantum gravity in finite regions. 
Some examples include the "$T\bar{T}$ deformation of two dimensional holographic CFTs, its generalisations and higher dimensional cousins.

Collection/Series: 
Scientific Areas: 
 

 

Jeudi aoû 02, 2018
Speaker(s): 

Despite being broadly accepted nowadays, temperature gradients in thermal equilibrium states continue to cause confusion, since they naively seem to contradict the laws of classical thermodynamics. In this talk, we will explore the physical meaning behind this concept, specifically discussing the role played by the university of free fall. We will show that temperature, just like time, is an observer dependent quantity and discuss why gravity is the only force capable of causing equilibrium thermal gradients without violating any of the laws of thermodynamics.

Collection/Series: 
Scientific Areas: 
 

 

Jeudi juin 28, 2018
Speaker(s): 

The entanglement entropy, while being under the spotlight of theoretical physics for more than ten years now, remains very challenging to compute, even in free quantum field theories, and a number of issues are yet to be explored.

Collection/Series: 
Scientific Areas: 
 

 

Vendredi juin 08, 2018
Speaker(s): 

I will discuss a proposed mechanism to fix the value of the top quark mass from asymptotic safety of gravity and matter, and will review the status of the proposal.

Collection/Series: 
Scientific Areas: 

Pages