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.
Title:
LQC: unfrequently asked questions
PDF [85K] of the slides
Audio [.mp3 6MB]
Title:
Stepping out of Homogeneity
in Loop Quantum Cosmology
PDF [122k] of the slides
Audio [.mp3 10MB]
Title: Quantum gravity perspective on AdS/CFT
PDF [10M] of the slides
Audio [.aif 1MB]
Audio [.mp3 89MB, complete]
Title: Manifestly gauge invariant relativistic pertrubation theory
PDF [1.3M] of the slides
Audio [.aif 3MB]
Audio [.wav 34MB, complete]
Title: Improved effective equations in loop quantum cosmology
PDF [380k] of the slides
Audio [.mp3 7MB] of the slides
Title: Self Dual Gravity
PDF [177k] of the slides
Audio [.mp3 10MB]
Title: Quantum gravity and the information loss problem
PDF [1.5M] of the slides
Audio [.aif 4MB]
Audio [.mp3 10MB, complete]
Title: Schwarzschild interior with loop quantum effects
PDF [150K] of the slides
Audio [.wav 35MB]
Audio [.aif 3.8MB]
Audio [.mp3 9MB, complete]
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]
Title: Computations involving SN, SF, QG and LGT.
PDF [600KB] of the slides
Audio [.wav 36MB]
Audio [.aif 4MB]
Title: Strong gravity and the BKL conjecture
PDF [260KB] of the slides
Audio [.mp3 8MB]
Audio [.aif 4MB]
of the slides
Title:
The loop quantum gravity vertex: a proposal
PDF [260KB] of the slides
Audio [.wav 42MB]
Audio [.aif 4MB]
Title:
Relational observables and cosmological perturbation theory
PDF [860KB] of the slides
Audio [.wav 38MB]
Audio [.aif 4MB]
Title:
Matter coupling to 3d quantum gravity and effective field theory I
PDF [10MB] of the slides
Audio [.mp3 65MB]
Audio [.aif 6MB]
Title:
The KITP program on quantum singularities (encore)
PDF [420K] of the slides
Audio [.mp3 12MB]
Audio [.aif 6MB]
Title:
Effective theories, continuum limit and background independence in LQG
PDF [ 370kb] of the slides
Audio [.mp3 53MB]
Audio [.aif 4MB]
Title:
Emergent chiral excitations of quantum geometries: progress report
PDF of the slides [5.5MB]
Audio [.mp3 56MB]
Audio [.aif 5MB]
Title:
Spherically symmetric loop quantum gravity
PDF of the slides [2MB]
Audio [.wav 26MB]
Audio [.aif 5MB]
Title:
Non metric gravity
PDF of the slides [128k]
Audio [.aif 6MB]
Audio [.wav 4MB]
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.
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.
Title:
Diffeomorphism invariance in LQG
PDF [105K] of the slides
Audio [.wav, 39MB]
Audio [.aif, 4MB]
Title:
KITP program on singularities summary
PDF [420K] of the slides
[there were problems with the audio, talk will be repeated 4/21]
Title: On the UV properties of N=8 supergravity: is it finite?
PDF [190K] of the slides
Audio [.wav, 38MB]
Audio [.aif, 4MB]
PDF [196K] of the slides
Audio [.wav, 29MB]
Audio [.aif, 3MB]
Title:
Approximate observables
PDF [171K] of the slides
Audio [.wav, 33MB]
Audio [.aif, 3MB]
PDF [171K] of the slides
Audio [.wav, 34MB]
Audio [.aif, 3MB]
PDF [430K] of the slides
Audio [.wav, 38MB]
Audio [.aif, 4MB]
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.
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]
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 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.