Archiv 2016

Raum: Seminar Room III, EG.080 Gastgeber: Martin Eckstein

Dynamical phase transitions in the long-range (powerlaw) interacting transverse-field Ising model

MPSD Seminar
Dynamical phase transitions (DPTs) have gained a lot of interest in the past few years in a variety of quantum many-body systems, where a system in its groundstate is quenched by abruptly changing a control parameter of the Hamiltonian, such as interaction strength or external field. Afterwards, a DPT can be detected in one of at least two forms: a type-I DPT which is detected, after relaxation in time, through the nonanalyticity of an appropriate order parameter as a function of the control parameter through which the quench is effected; and a type-II DPT which is detected as a nonanalyticity of the Loschmidt echo return rate as a function in time, without giving care as to whether or not a stationary state has been reached in the time evolution. [mehr]

Nonequilibrium dynamics of strongly coupled phonon-mediated superconductors

CFEL Theory Seminar
Recent developments in ultra-fast laser techniques allow experimentalists to reveal intriguing aspects of the dynamics of superconductors such as the Higgs oscillations (amplitude oscillations of the order parameter) and photo-induced superconductivity. These experiments demonstrate the interesting possibility of manipulating superconductivity in nonequilibrium settings. However, the properties of nonequilibrium superconductors are not fully understood, and further theoretical explorations are needed. [mehr]
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