title: Quantum diffusion in a fermionic bath.
abstract: We propose a scheme for quantum brownian motion of a particle in a fermionic bath. Based on the spin coherent-state representation of the noise operators and a canonical thermal distribution of the associated c numbers, we derive a quantum analog of generalized Langevin equation for quantum-mechanical mean position of the particle subjected to an external force field. The approach allows us to map the quantum problem on a classical setting. The quantum dispersion around the mean can be estimated order by order by a set of quantum correction equations up to a desired degree of accuracy for a given nonlinear potential. We derive a quantum diffusion equation for free particle and show that quantization, in general, enhances the mean-square displacement. Increase in temperature leads to suppression of mean-square displacement. The method is based on canonical quantization procedure and may be used for understanding diffusive transport and thermally activated processes in a fermionic bath.
authors.affiliation: Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
authors.forename: Sudarson Sekhar
authors.initials: SS
authors.lastname: Sinha
authors.forename: Debasish
authors.initials: D
authors.lastname: Mondal
authors.forename: Bidhan Chandra
authors.initials: BC
authors.lastname: Bag
authors.forename: Deb Shankar
authors.initials: DS
authors.lastname: Ray