Past Quantum Field Theory Seminar

18 January 2011
12:00
Prakash Panangaden (McGill, visiting Comlab)
Abstract
Communication between observers in a relativistic scenario has proved to be a setting for a fruitful dialogue between quantum field theory and quantum information theory. A state that an inertial observer in Minkowski space perceives to be the vacuum will appear to an accelerating observer to be a thermal bath of radiation. We study the impact of this Davies-Fulling-Unruh noise on communication, particularly quantum communication from an inertial sender to an accelerating observer and private communication between two inertial observers in the presence of an accelerating eavesdropper. In both cases, we establish compact, tractable formulas for the associated communication capacities assuming encodings that allow a single excitation in one of a fixed number of modes per use of the communications channel.
  • Quantum Field Theory Seminar
2 November 2010
12:00
Francis Bursa (Cambridge)
Abstract
String field theory is a candidate for a full non-perturbative definition of string theory. We aim to define string field theory on a space-time lattice to investigate its behaviour at the quantum level. Specifically, we look at string field theory in a one dimensional linear dilaton background, using level truncation to restrict the theory to a finite number of fields. I will report on our preliminary results at level-0 and level-1.
  • Quantum Field Theory Seminar
19 October 2010
12:00
Subir Sarkar (Theoretical Physics)
Abstract
Much effort has been devoted to the study of weak scale particles, e.g. supersymmetric neutralinos, which have a relic abundance from thermal equilibrium in the early universe of order what is inferred for dark matter. This does not however provide any connection to the comparable abundance of baryonic matter, which must have a non-thermal origin. However "dark baryons" of mass ~5 GeV from a new strongly interacting sector would naturally provide dark matter and are consistent with recent putative signals in experiments such as CoGeNT and DAMA. Such particles would accrete in the Sun and affect heat transport in the interior so as to affect low energy neutrino fluxes and can possibly resolve the current conflict between helioseismological data and the Standard Solar Model.
  • Quantum Field Theory Seminar
15 June 2010
12:00
Varghese Mathai (Adelaide)
Abstract
I will define and discuss the properties of the analytic torsion of twisted cohomology and briefly of Z_2-graded elliptic complexes in general, as an element in the graded determinant line of the cohomology of the complex, generalizing most of the variants of Ray- Singer analytic torsion in the literature. IThe definition uses pseudo- differential operators and residue traces. Time permitting, I will also give a couple of applications of this generalized torsion to mathematical physics. This is joint work with Siye Wu.
  • Quantum Field Theory Seminar

Pages