Dark Bell states in tunnel-coupled spin qubits

TL;DR

This paper explores how resonant ac driving and coherent tunneling in coupled quantum dots can dynamically generate and maintain dark Bell states, which are maximally entangled electron states decoupled from the environment, with potential experimental signatures in transport spectroscopy.

Contribution

It introduces a method to produce and identify dark Bell states in tunnel-coupled spin qubits using resonant ac driving, advancing quantum control techniques.

Findings

Dark Bell states exhibit Rabi oscillations under resonant driving.

Dark states remain spatially separated, reducing decoherence.

Proposed transport spectroscopy signatures for experimental detection.

Abstract

We investigate the dynamical purification of maximally entangled electron states by transport through coupled quantum dots. Under resonant ac driving and coherent tunneling, even-parity Bell states perform Rabi oscillations that decouple from the environment, leading to a dark state. The two electrons remain spatially separated, one in each quantum dot. We propose configurations where this effect will prove as antiresonances in transport spectroscopy experiments.