Electron-nuclear dynamics in a quantum dot under non-unitary electron control

TL;DR

This paper presents a new method for modeling the non-unitary dynamics of an electron spin in a quantum dot interacting with nuclei, incorporating external controls and environmental effects, with implications for nuclear relaxation rates.

Contribution

It introduces a novel approach to account for non-unitary evolution in quantum dot electron-nuclear systems under external control and environmental interactions.

Findings

Nuclear relaxation rates are significantly faster than previously reported.

The method accurately models nuclear-induced frequency focusing.

External controls and environment effects are effectively incorporated.

Abstract

We introduce a method for solving the problem of an externally controlled electron spin in a quantum dot interacting with host nuclei via the hyperfine interaction. Our method accounts for generalized (non-unitary) evolution effected by external controls and the environment, such as coherent lasers combined with spontaneous emission. As a concrete example we develop the microscopic theory of the dynamics of nuclear-induced frequency focusing, as first measured in Science 317, 1896 (2007); we find that the nuclear relaxation rates are several orders of magnitude faster than those quoted in that work.