Triangle Seminars
Monday, 15 Jan 2007
Black holes, qubits and the Fano plane
Mike Duff
(Imperial College)
Tuesday, 16 Jan 2007
Wavepacket dynamics of the nonlinear Harper model
Tsampikos Kottos
(MPI Goettingen)
Abstract:
The destruction of anomalous diffusion of the Harper model at
criticality, due to weak non-linearity chi is analyzed. It
is shown that the second moment grows sub-diffusively as its expectation value is proportional to t to the power alpha, up to times t star proportional to chi to the power gamma. The exponents alpha and gamma reflect the multifractal properties of the spectra and eigenfunctions of the linear model. For t larger than t star the anomalous diffusion law is recovered, however the evolving profile has different shape with respect to the linear case. Applications to waveguide structures, and arrays of magnetic micro-traps for atomic Bose-Einstein condensates are discussed.
The destruction of anomalous diffusion of the Harper model at
criticality, due to weak non-linearity chi is analyzed. It
is shown that the second moment grows sub-diffusively as its expectation value is proportional to t to the power alpha, up to times t star proportional to chi to the power gamma. The exponents alpha and gamma reflect the multifractal properties of the spectra and eigenfunctions of the linear model. For t larger than t star the anomalous diffusion law is recovered, however the evolving profile has different shape with respect to the linear case. Applications to waveguide structures, and arrays of magnetic micro-traps for atomic Bose-Einstein condensates are discussed.
Posted by: brunel
Wednesday, 17 Jan 2007
The dynamics of cosmic superstrings
📍 London
Edmund Copeland
(University of Nottingham)
Thursday, 18 Jan 2007
Duality Groups, Automorphic Forms and Higher Derivative Corrections
Neil Lambert
(King's College)
Abstract:
We discuss how the duality group G controls the higher derivative corrections that arise in the effective action of M-theory compactified on a torus.
In particular we show that the perturbative contributions always involve the weights of G and that this is a consequence of the appearance of automorphic forms of G in the complete quantum effective action.
We discuss how the duality group G controls the higher derivative corrections that arise in the effective action of M-theory compactified on a torus.
In particular we show that the perturbative contributions always involve the weights of G and that this is a consequence of the appearance of automorphic forms of G in the complete quantum effective action.
Posted by: IC
Twisted Tori and (New) String Vacua
Ruben Minasian
(CEA/Saclay)