Entanglement of solid-state qubits by measurement

TL;DR

This paper demonstrates that two identical solid-state qubits can be fully entangled with a probability of 1/4 through measurement, using either strong projective or weak continuous measurement, with specific spectral signatures indicating entanglement.

Contribution

It introduces a measurement-based entanglement scheme for solid-state qubits, showing how measurement can induce entanglement with high probability and identifying spectral signatures of entanglement.

Findings

Entanglement achieved with probability 1/4 via measurement.

Spectral analysis distinguishes entangled from non-entangled states.

Weak measurement yields identifiable spectral signatures of entanglement.

Abstract

We show that two identical solid-state qubits can be made fully entangled (starting from completely mixed state) with probability 1/4 just measuring them by a detector, equally coupled to the qubits. This happens in the case of repeated strong (projective) measurements as well as in a more realistic case of weak continuous measurement. In the latter case the entangled state can be identified by a flat spectrum of the detector shot noise, while the non-entangled state (probability 3/4) leads to a spectral peak at the Rabi frequency with the maximum peak-to-pedestal ratio of 32/3.