Abstract
Quantum coherence of superposed states, especially of entangled states, is indispensable for many quantum technologies. However, it is vulnerable to environmental noises, posing a fundamental challenge in solid-state systems including spin qubits. Here we show a scheme of entanglement engineering where pure dephasing assists the generation of quantum entanglement at distant sites in a chain of electron spins confined in semiconductor quantum dots. One party of an entangled spin pair, prepared at a single site, is transferred to the next site and then adiabatically swapped with a third spin using a transition across a multi-level avoided crossing. This process is accelerated by the noise-induced dephasing through a variant of the quantum Zeno effect, without sacrificing the coherence of the entangled state. Our finding brings insight into the spin dynamics in open quantum systems coupled to noisy environments, opening an avenue to quantum state manipulation utilizing decoherence effects.
Highlights
1,2,3, Shinichi Amaha[1], Jun Yoneda 1, 5, Andreas D
In semiconductor quantum dot (QD) devices, potential building blocks of spinbased quantum computers, a great deal of effort have been made to mitigate the decoherence by engineering[1,2], controlling[3], and measuring[4,5] the environmental noise sources
The decoherence effect is significant in entangling gate operations for spin qubits because they are implemented by electrically tuning exchange coupling, which makes these qubits sensitive to charge noise[6]
Summary
1,2,3, Shinichi Amaha[1], Jun Yoneda 1, 5, Andreas D. Numerical simulations show that the adiabatic spin swap is assisted by strong dephasing noise, which can be interpreted as a manifestation of the quantum Zeno effect.
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