This is a seminar on research that takes place every Tuesday at 9am (US Central Time). Audio is distributed via telephone. Slides of the talks are posted in advance here. Talks are recorded and the audio posted here. Among the groups that participate live are PennState, Perimeter Institute, Marseille, AEI-Potsdam, Utrecht, UNAM-Mexico, FUW-Poland, CSIC-Madrid, UDELAR, Uruguay, UWO-Canada, UNB-Canada, Umass Dartmouth, Hamilton College, LSU. Others may join soon. Unfortunately, the phone bridge we have has a limited number of lines so we cannot open live participation to everyone. If your group wishes to participate, please write to pullin at lsu.edu. Locally at LSU, we listen to the talks in 241 Nicholson Hall. You are welcome to join the mailing list.

Seminars will restart in the fall of 2008.

Tuesday, May 6th

**Title:**
LQC: unfrequently asked questions

PDF [85K] of the slides

Audio [.mp3 6MB]

Tuesday, April 22nd

**Title:**
Stepping out of Homogeneity
in Loop Quantum Cosmology

PDF [122k] of the slides

Audio [.mp3 10MB]

Tuesday, April 8th

**Title:** Quantum gravity perspective on AdS/CFT

PDF [10M] of the slides

Audio [.aif 1MB]
Audio [.mp3 89MB, complete]

Tuesday, Mar 25th

**Title:** Manifestly gauge invariant relativistic pertrubation theory

PDF [1.3M] of the slides

Audio [.aif 3MB]
Audio [.wav 34MB, complete]

Tuesday, Feb 19th

**Title:** Improved effective equations in loop quantum cosmology

PDF [380k] of the slides

Audio [.mp3 7MB] of the slides

Tuesday, Feb 5th

**Title:** Self Dual Gravity

PDF [177k] of the slides

Audio [.mp3 10MB]

Tuesday, Jan 22nd

**Title:** Quantum gravity and the information loss problem

PDF [1.5M] of the slides

Audio [.aif 4MB]
Audio [.mp3 10MB, complete]

Tuesday, Nov 27th

**Title:** Schwarzschild interior with loop quantum effects

PDF [150K] of the slides

Audio [.wav 35MB]
Audio [.aif 3.8MB]
Audio [.mp3 9MB, complete]

Tuesday, Nov 13th

**Title:** A connection with everything.

PDF [2MB] of the slides

alternate PDF [8MB] of the slides

Audio [.wav 30MB]
Audio [.aif 3MB]
Audio [.mp3 7MB, complete]

Tuesday, Oct 30

**Title:** Computations involving SN, SF, QG and LGT.

PDF [600KB] of the slides

Audio [.wav 36MB]
Audio [.aif 4MB]

Tuesday, Oct 16

**Title:** Strong gravity and the BKL conjecture

PDF [260KB] of the slides

Audio [.mp3 8MB]
Audio [.aif 4MB]
of the slides

Tuesday, Sep 18th (at 9:15 AM US Central time)

**Title:**
The loop quantum gravity vertex: a proposal

PDF [260KB] of the slides

Audio [.wav 42MB]
Audio [.aif 4MB]

Tuesday, Sep 4th (at 9:15 AM US Central time)

**Title:**
Relational observables and cosmological perturbation theory

PDF [860KB] of the slides

Audio [.wav 38MB]
Audio [.aif 4MB]

Tuesday, May 15th

**Title:**
Matter coupling to 3d quantum gravity and effective field theory I

PDF [10MB] of the slides

Audio [.mp3 65MB]
Audio [.aif 6MB]

Tuesday, April 24th

**Title:**
The KITP program on quantum singularities (encore)

PDF [420K] of the slides

Audio [.mp3 12MB]
Audio [.aif 6MB]

Tuesday, April 10th

**Title:**
Effective theories, continuum limit and background independence in LQG

PDF [ 370kb] of the slides

Audio [.mp3 53MB]
Audio [.aif 4MB]

Tuesday, April 3rd

**Title:**
Emergent chiral excitations of quantum geometries: progress report

PDF of the slides [5.5MB]

Audio [.mp3 56MB]
Audio [.aif 5MB]

Tuesday, March 27th

**Title:**
Spherically symmetric loop quantum gravity

PDF of the slides [2MB]

Audio [.wav 26MB]
Audio [.aif 5MB]

Tuesday, March 20th

**Title:**
Non metric gravity

PDF of the slides [128k]

Audio [.aif 6MB]
Audio [.wav 4MB]

Tuesday, March 13th

**Title:**
Quantum fields and Noether charges for kappa-spacetime symmetries

PDF of the slides [268k]

Audio [.aif, 8MB]
Audio [.wav, 4MB]

**Abstract: **
After a brief review of the kappa-Poincare' Hopf algebra I will
discuss how it can be used to describe the symmetries of
kappa-Minkowski non-commutative spacetime. In particular I will
focus on how apparent ambiguities in defining the action of
translations can be overcome and how conserved Noether charges can be
associated with such symmetries. Moving from the classical to the
quantum field framework, I will first recall some older results on
perturbative calculations in a path-integral approach for phi^4
scalar field theory. I will then show how recent work on the
symplectic structure of classical kappa-fields suggests a new
approach to canonical quantization of free fields and I will close
with some remarks on the recent efforts and results on such topic.

Tuesday, March 6th

**Title:**
Relation between Schroedinger and polymer quantum mechanics

PDF of the slides [190k]

Audio [.aif, 8MB]

**Abstract:**

The relation between the ordinary Schroedinger representation and the
so-called polymer representation will be explored. We will show how
the polymer representation can be obtained as an appropriate limit of
the Schroedinger one, and how we can recover this one by means of a
precise renormalization procedure of the polymer quantum
mechanics. Some examples will be discussed.

Tuesday February 27th

**Title:**
Diffeomorphism invariance in LQG

PDF [105K] of the slides

Audio [.wav, 39MB]
Audio [.aif, 4MB]

Tuesday February 20th

**Title:**
KITP program on singularities summary

PDF [420K] of the slides

[there were problems with the audio, talk will be repeated 4/21]

Tuesday February 13th

**Title:**
On the UV properties of N=8 supergravity: is it finite?

PDF [190K] of the slides

Audio [.wav, 38MB]
Audio [.aif, 4MB]

Tuesday November 28th

PDF [196K] of the slides

Audio [.wav, 29MB]
Audio [.aif, 3MB]
**Title:**
Approximate observables

Tuesday November 7th

PDF [171K] of the slides

Audio [.wav, 33MB]
Audio [.aif, 3MB]

Tuesday November 7th

PDF [171K] of the slides

Audio [.wav, 34MB]
Audio [.aif, 3MB]

Tuesday October 31st.

PDF [430K] of the slides

Audio [.wav, 38MB]
Audio [.aif, 4MB]

Tuesday October 17th.

PDF [700K] of the slides

Audio [.wav, 41MB]
Audio [.aif, 4MB]

**Abstract: **
In quantum field theory, knowing all transition amplitudes or the
S-matrix is usually considered sufficient to specify the physical
content of a theory. We are often accustomed to adopt a similar
attitude when developing quantum gravity, concentrating on technical
advances. I want to start this talk with a reminder that conceptual
problems with the physical interpretation of quantities in quantum
gravity remain open. In particular, I will review the problem of time
and what I shall call the quantum cosmology problem. I will then
review the general boundary formulation of quantum theory and explain
in which sense it addresses these problems. The key conceptual step in
this is a generalization of the probability rule of quantum theory and
of the associated notion of probability conservation. Finally, I want
to discuss the recent application of the general boundary formulation
in the context of graviton amplitudes from a conceptual point of view.

Tuesday October 10th.

PDF [180K] of the slides

Audio [.wav, 31MB]
Audio [.aif, 3MB]

Tuesday October 3rd.

**Simone Speziale, Perimeter Institute**

**Title:** Graviton propagator from loop quantum gravity II

PDF [1MB] of the slides

Audio [.wav, 40MB]
Audio [.aif, 4MB]

Tuesday September 26th.

PDF [2MB] of the slides

Audio [.wav, 44MB]
Audio [.aif, 4.6MB]

Tuesday September 19th.

** Abhay Ashtekar, PennState**

**Title:**
Loop quantum gravity frequently asked questions

PDF [46kb] of the slides

Audio [.wav, 33MB]
Audio [.aif, 3MB]

**Abstract:**

This is based on the MG11 invited talk

Tuesday June 27th.

** Frank Saueressig, Utrecht**

**Title:**
Renormalization group improved cosmologies

PDF [223k] of the slides

Audio [.wav, 33MB]
Audio [.aif, 3MB]

**Abstract:**

Title:
Renormalization group improved cosmologies
Abstract:
It is generally believed that in the very early universe, at times smaller
than the Planck time, quantum gravity effects play a crucial role. Since the
physics in the Planck era prepares the initial conditions for the subsequent
classical evolution of the universe it is desirable to gain some
understanding of the quantum gravitational processes which took place
immediately after the Big Bang. Based on the Einstein-Hilbert approximation
of asymptotically safe quantum gravity we discuss a consistent
renormalization group based framework which allows for the inclusion of such
quantum gravitational effects into the cosmological field equations and
applies to all stages of the cosmological evolution. The very early universe
is found to contain a period of "oscillatory inflation". Lateron the
cosmological evolution is classical and asymtotes to a de Sitter era at
cosmologically late times.

Tuesday June 20th.

** Andrzej Okolow, Warszaw**

**Title:** Quantization of diffeomorphism invariant theories of connections
with a non-compact structure group --- an example

PDF [250k] of the slides

Audio [.wma, 33MB]
Audio [.wav, 48MB]
Audio [.aif, 3.5MB]

**Abstract:**

A simple diffeomorphism invariant theory of connections with the
non-compact structure group R of real numbers is quantized. The theory
is defined on a four-dimensional 'space-time' by an action resembling
closely the self-dual Plebanski action for general relativity. The space
of quantum states is constructed by means of projective techniques by
Kijowski. Except this point the applied quantization procedure
is based on Loop Quantum Gravity methods.

Tuesday June 13th.

Tuesday June 6th.

** Parampreet Singh (PennState). **

**Title:** The Big Bang and Loop Quantum Cosmology

PDF [1 MB] of the slides

Audio [.wav, 35MB]
Audio [.aif, 3.7MB] of the talk
of the talk

**Abstract:**

The talk deals with the recent developments in homogeneous and
isotropic loop quantum cosmology on the Planck scale physics near the Big
Bang. By constructing the physical Hilbert space, Dirac observables
and physical semi-classical states definite and robust predictions
about quantum nature of big bang can be made. The analysis leads to
a prediction that the current, classical, expanding phase of the Universe
is deterministically joined to a contracting phase by a quantum
gravitational bridge. Quantum geometric effects at Planck scales make
gravity replusive replacing big bang singularity with a big bounce.
Slides will be posted here on Monday. Audio will be posted after the talk.