Tentative Schedule
September 19, 2011
Speaker: Sergei Dubovsky, New York University
Title: "Superluminal Travel in the Lineland"
September 26, 2011
Speaker: Emil Mottola, Los Alamos National Laboratory
Title: "New Horizons in Gravity: The Trace Anomaly and Its Macroscopic Quantum Effects in 'Black Holes' and Cosmology"
Abstract:
Anomalies are classical symmetries that cannot be maintained at the quantum level. In the familiar axial anomaly in QED and QCD, massless poles necessarily arise
from anomalous Ward identities. These massless poles in two-particle intermediate
states are non-local quantum pair correlated states, described by an effective local Lagrangian containing additional pseudoscalar degrees of
freedom, not present in the classical theory. The stress tensor contains
a similar anomaly in its trace, which leads to additional scalar degrees of freedom not present in the classical Einstein theory. Thus General Relativity receives quantum
corrections from Standard Model fields which can become significant in macroscopic
systems and in particular near black hole and cosmological event horizons.
The region near the classical event horizon of a fully collapsed star may then be instead a quantum boundary layer where the effective value of the gravitational
vacuum energy density can change. By taking a positive value in the interior, the
vacuum energy removes any singularity, replacing it with a smooth dark energy interior.
The observed dark energy of our universe likewise may be a macroscopic finite size effect
whose value depends not on microphysics but on the cosmological horizon itself.
October 3, 2011
Speaker: Yasunori Nomura, University of California, Berkeley
Title: "Physical Predictions in the Quantum Multiverse"
Abstract:
I describe how quantum mechanics plays a crucial role
in defining probabilities (the "measure") in the multiverse. The
resulting picture leads to a dramatic change of our view on
spacetime and gravity, and provides complete unification of the
eternally inflating multiverse and many worlds in quantum mechanics.
The latest result on the distribution of the cosmological constant
is also presented.
October 10, 2011
Speaker: Daniel Green, Institute for Advanced Study, Princeton University
Title: "Signatures of Supersymmetry from the Early Universe"
Abstract:
Supersymmetry plays a fundamental role in the radiative stability of
many inflationary models. I will explain how supersymmetry and
naturalness require additional scalar degrees of freedom with masses on
the order of the inflationary Hubble scale. These fields lead to
distinctive non-gaussian signatures that may be observable in both the
CMB and large scale structure.
October 17, 2011
Speaker: Professor Antonio Delgado, Notre Dame University
Title: "The S-MSSM: the singlet saves the day"
Abstract:
The LEP bound on the Higgs mass has created a problem within the MSSM,
the little hierarchy problem. I will present a model in which that
problem is solved via a singlet whose sole role is to increase the Higgs
mass at tree-level and not to solve the mu problem as in the usual
NMSSM.
October 24, 2011
Speaker: Rafael Porto, Institute for Advanced Study
Title: "Dissipative effects during inflation: An effective field theory approach"
Abstract:
Using an approach originally developed to study gravitational wave
absorption in black hole binary systems, we generalize the EFT of single
clock inflation to include dissipative effects. We show that in the
presence of dissipation/fluctuation the computation of the power
spectrum is significantly modified, and moreover non-gaussianities can
be enhanced with respect to the case without additional degrees of
freedom by a factor of \gamma/H, where \gamma is the `friction'
coefficient. We also discuss the matching of the EFT with a few key
examples such as trapped and warm inflation.
October 31, 2011
Speaker: Ben Freivogel, University of California, Santa Barbara
Title: "Exactly stable collective oscillations in conformal field theory"
November 14, 2011
Speaker: Professor Zohar Komargodski,Weizmann/IAS Princeton
Title: "Renormalization Group Flows in Diverse Dimensions"
Abstract:
If the coupling constants in a general QFT are promoted to functions of
space-time, the dependence of the path integral on these couplings is
highly constrained by conformal symmetry. We use this simple observation
to derive the $a$-theorem. We also study simple examples of the general
procedure. Finally, we discuss the dependence on the coupling constants
in arbitrary two-dimensional RG flows. The constraints of conformal symmetry lead to a new proof of Zamolodchikov's theorem.
December 5, 2011
Speaker: Raphael Bousso, UC Berkeley
Title: "A Geometric Solution to the Coincidence Problem, and the Size of the Landscape as the Origin of Hierarchy"
Abstract:
Without assuming necessary conditions for observers such as galaxies or
entropy production, we show that the causal patch measure predicts the
coincidence of vacuum energy and present matter density. Their common
scale, and thus the enormous size of the visible universe, has its
origin in the number of metastable vacua in the landscape.
December 19, 2011
Speaker: Mark Jackson, APC Paris
Title: "Effective Field Theory in Inflation"
Abstract:
Although the observed CMB is at very low energy, it encodes ultra
high-energy physics in spatial variations of the photon temperature and
polarization fluctuations. This effect is believed to be dominated by
the initial quantum state of the Universe. I will describe the first
theoretical tools by which to construct such a state from fundamental
physics. One can then use this technique to reliably calculate
corrections to the power spectrum, non-Gaussianity, etc from high-energy
physics. We may soon be able to compare these predictions against
experiment, allowing one to rule out classes of quantum gravity models.
Now is the critical time to undertake such investigations, with a
number of ongoing and planned experiments such as Planck and
CMBPol/Inflation Probe poised to collect a wealth of precision data.
