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DY: Fachverband Dynamik und Statistische Physik

DY 53: Poster: Quantum Dynamics, Chaos and Information; Many Body Systems

DY 53.2: Poster

Donnerstag, 19. März 2020, 15:00–18:00, P1A

Wave Functions in White Noise Potential: Spreading or Localization? — •Marco Hofmann and Barbara Drossel — Institute of Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstr. 6, 64289 Darmstadt, Germany

We study the dynamics of a quantum wave function on a 1D lattice subject to a fluctuating potential that is described as uncorrelated Gaussian white noise. Starting from a stochastic Schrödinger equation, we derive the corresponding Lindblad equation. This Lindblad equation, in turn, can be unravelled in terms of stochastic wave function dynamics in several different ways, all of which are empirically equivalent, as the density matrix alone determines the outcome of measurements. Two of these unravellings are widely used in the theory of Open Quantum Systems, namely the Quantum State Diffusion Model and the Quantum Jump Method. We show that the degree of localization or spreading of the wave function depends on the type of unravelling used, and in particular on the way the trace-conserving term of the Lindblad equation is implemented in the wave function dynamics. Part of the implementations lead to the localization of the wave function on a limited number of lattice sites. Our results raise interesting questions related to the interpretation of the wave function.