An Anisotropic Landau-Lifschitz-Gilbert model of dissipation in qubits

TL;DR

This paper develops a microscopic anisotropic Landau-Lifschitz-Gilbert model for qubit dissipation, applicable to superconducting flux qubits, revealing how environmental coupling influences quantum dynamics and trajectory bias.

Contribution

It introduces a generalized anisotropic dissipative model for interacting qubits coupled to a thermal bath, extending previous phenomenological models.

Findings

Model applies to superconducting flux qubits with anisotropic environmental coupling

Dissipation biases quantum trajectories towards reduced phase space

Dynamics resemble phenomenological models used in quantum computing

Abstract

We derive a microscopic model for dissipative dynamics in a system of mutually interacting qubits coupled to a thermal bath that generalises the dissipative model of Landau-Lifschitz-Gilbert to the case of anisotropic bath couplings. We show that the dissipation acts to bias the quantum trajectories towards a reduced phase space. This model applies to a system of superconducting flux qubits whose coupling to the environment is necessarily anisotropic. We study the model in the context of the D-Wave computing device and show that the form of environmental coupling in this case produces dynamics that are closely related to several models proposed on phenomenological grounds.