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DY: Dynamik und Statistische Physik

DY 27: Quantenchaos II

DY 27.5: Vortrag

Dienstag, 12. März 2002, 17:30–17:45, H3

Isothermal quantum dynamics: Nosé-Hoover method for coherent states — •D. Mentrup and J. Schnack — Universität Osnabrück, Fachbereich Physik, Barbarastr. 7, 49069 Osnabrück

The popular method of Nosé and Hoover uses pseudofriction terms to create canonically distributed positions and momenta in classical molecular dynamics simulations. We show that it may be transferred to a genuine quantum system of infinite dimensionality.

For quantum particles in an external harmonic oscillator potential, time-dependent pseudofriction terms may be introduced into the quantum equations of motion of coherent states to mimic the coupling of the system to a thermal bath. The time evolution of the pseudofriction coefficients is derived from a generalized Liouville equation on a mixed quantum-classical phase space to create a quantum canonical ensemble.

We present the resulting time evolutions for bosons and fermions that feature Bose attraction and Pauli blocking, and discuss the question of ergodicity for different coupling schemes. Possible applications to more complex systems, especially interacting Fermion systems, are proposed.