Decoherence induced by electron accumulation in quantum measurement of charge qubits

TL;DR

This paper investigates how electron accumulation during quantum measurement causes decoherence in charge qubits, using a master equation approach to understand the dynamics and effects on qubit coherence.

Contribution

It introduces a master equation framework to analyze decoherence caused by electron accumulation in charge qubit measurements with quantum point contacts.

Findings

Electron accumulation leads to measurable decoherence effects.

The derived equations quantify the impact of electron tunneling on qubit coherence.

Results provide insights into minimizing decoherence in quantum measurements.

Abstract

In this paper, we study the quantum decoherence induced by accumulation of electron tunnelings during the quantum measurement of a charge qubit. The charge qubit is a single electron confined in coupled quantum dots. The measurement of the qubit states is performed using a quantum point contact. A set of master equations for qubit states is derived within a nonequilibrium perturbation to the equilibrium reservoir due to the electron accumulation between the source and drain of the quantum point contact. The quantum decoherence of the qubit states arose from the electron accumulation during the measurement is explored in this framework, and several interesting results on charge qubit decoherence are obtained.