Qubit-environment entanglement outside of pure decoherence: hyperfine interaction

TL;DR

This paper reviews hyperfine interaction-induced decoherence in spin qubits and investigates how qubit-environment entanglement evolves with environment size and magnetic field, revealing key dynamics of decoherence processes.

Contribution

It provides a theoretical analysis of qubit-environment entanglement dynamics considering environment size and magnetic field effects, extending understanding beyond pure decoherence models.

Findings

Negativity varies with environment size and nuclear spin configurations.

Magnetic field influences qubit-environment disentangling times.

Entanglement persists outside of pure decoherence regimes.

Abstract

In spin-based architectures of quantum devices, the hyperfine interaction between the electron spin qubit and the nuclear spin environment remains one of the main sources of decoherence. This paper provides a short review of the current advances in the theoretical description of the qubit decoherence dynamics. Next, we study the qubit-environment entanglement using negativity as its measure. For an initial maximally mixed state of the environment, we study negativity dynamics as a function of environment size, changing the numbers of environmental nuclei and the total spin of the nuclei. Furthermore, we study the effect of the magnetic field on qubit-environment disentangling time scales.