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DY: Fachverband Dynamik und Statistische Physik

DY 28: Statistical Physics far from Equilibrium

DY 28.3: Talk

Thursday, March 17, 2011, 10:45–11:00, HÜL 186

Investigations of unconventional quantum statistics in isolated spin clusters — •Kai Ji and Boris Fine — Institute for Theoretical Physics, University of Heidelberg, Philosophenweg 19, 69120 Heidelberg, Germany

Quantum micro-canonical (QMC) ensemble refers to an isolated quantum system with fixed average energy but unrestricted participation of eigenstates. The QMC ensemble reveals marked deviation from the conventional Boltzmann-Gibbs (BG) statistics [1]. In this work, based on an anisotropic Heisenberg model, we perform numeral investigations on the statistics of QMC ensemble and discuss the physical realization of it in isolated spin clusters. The exploration for superpositions of quantum states in the Hilbert space is proposed to be driven by strong perturbations with a series of magnetic pulses. It is demonstrated that starting from a BG distribution, the occupation numbers universally evolve to the distribution obtained in Ref. [1] before reaching the infinite temperature limit, indicating the onset of QMC ensemble. Possible ways for detecting the established QMC ensemble is to be addressed as well.

[1] B.V. Fine, Phys. Rev. E 80, 051130 (2009).