Visit by Andrzej Krolak

 

Prof. Krolak  from Institute of Mathematics, Polish Academy of Sciences at Warsaw is visiting us from Nov 27-Dec 6, 2017. Prof. Krolak has made very seminal contributions to our understanding of strength of singularities, and various aspects of theoretical gravity and gravitational waves. He is the head of the Polish gravitatioanal wave community involved with Virgo gravitational wave detector.

You are welcome to discuss with Andrzej in room 255.

Talk by Andrea Dapor

Speaker: Andea Dapor, FAU-Erlangen, Germany
Place: 241 Nicholson
Date: Tuesday November 14th
Time: 9am

Title: Coherent States in LQG: Cosmology, Black Holes and Effective Dynamics

Seminar by Prof. Christian Fleischhack

Seminar by 

Prof. Christian Fleischhack

 

Symmetries in loop quantum gravity

 

Date: Aug 30, 2017

Time: 11:30 AM

Gravity Suite

Talk by Raul Carballo-Rubio

Seminar by Raul Carballo-Rubio

Talk time and date:

May 17th at 11:00 AM in Nicholson 241

 

Title:  Exponential decay of black holes into white holes

Abstract: In recent years, it has been proposed by different authors that non-perturbative quantum gravity effects may turn black holes into white holes. To evaluate the characteristic time scale of this transition, a theory of quantum gravity that assigns probabilities to geometric interpolations between black hole and white hole geometries is needed. In this talk, I will explain the results that are obtained in a truncation of the problem that assigns probabilities à la Euclidean quantum gravity to a reduced set of interpolating geometries. I will show how an exact exponential decay law is found, extract the characteristic time scale that follows from it, and discuss the astrophysical relevance of this calculation.

Seminar by Andrzej Krolak

Seminar by Andrzej Krolak

 

Strong curvature singularities 

- past and future

 

Time: 12:30 PM 

Date: March 23, 2017

Gravity Suite

 

Seminar by Lucas Fabian

Seminar by Lucas Fabian

Talk time and date:

March 21th at 11:00 AM in Nicholson 241

 

 

 

 

 

 

 

 

Title: Review / progress report on entanglement of squeezed vacua

Abstract: There is a lot of ongoing work using complex structures to study power spectrum and entanglement entropy of scalar perturbations in cosmology. I will review our general methods and explain the machinery connecting entanglement entropy, correlation function and complex structure for Gaussian states. There are some subtleties when going from finitely many degrees of freedom to infinitely many, due to unitarily inequivalent representations. A recent progress provided an elegant method of finding adiabatic vacua using an ε expansion of the complex structure, rather than going through the standard WKB approximation. This aspect is still incomplete, but I will explain the general approach.

Seminar by Lucas Fabian

Seminar by Lucas Fabian

Talk time and date:

March 20th at 1:30 AM in Nicholson 241

 

 

 

 

 

 

 

 

Title: Entanglement production at parametric resonance

Abstract: The most prominent example in cosmology is the reheating phase where one couples a test scalar matter field to the inflaton field treated as a classical source.  Our result is a generic theorem stating that the entanglement entropy associated to a detector grows linearly in time with a slope given by the Floquet exponents associated to resonant modes.