Qubit decoherence due to detector switching

TL;DR

This paper analyzes how switching detectors cause decoherence in qubits during measurement, offering a simple analytical approach and exploring the balance between measurement speed and invasiveness.

Contribution

It introduces a straightforward method to analytically evaluate qubit dephasing and errors caused by switching detectors, applicable to various quantum systems.

Findings

Switching detectors induce decoherence during qubit escape events.

Fast measurements with weak invasiveness are possible using switching detectors.

Intrinsic symmetry can invert errors, affecting measurement fidelity.

Abstract

We provide insight into the qubit measurement process involving a switching type of detector. We study the switching-induced decoherence during escape events. We present a simple method to obtain analytical results for the qubit dephasing and bit-flip errors, which can be easily adapted to various systems. Within this frame we investigate potential of switching detectors for a fast but only weakly invasive type of detection. We show that the mechanism that leads to strong dephasing, and thus fast measurement, inverts potential bit flip errors due to an intrinsic approximate time reversal symmetry.