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arXiv · 2108.07365

Bell-state generation for spin qubits via dissipative coupling

Ji Zou·Shu Zhang·Yaroslav Tserkovnyak
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Abstract

We theoretically investigate the dynamics of two spin qubits interacting with a magnetic medium. A systematic formal framework for this qubit-magnet hybrid system is developed in terms of the steady-state properties of the magnetic medium. Focusing on the induced dissipative coupling between the spin qubits, we show how a sizable long-lived entanglement can be established via the magnetic environment, in the absence of any coherent coupling. Moreover, we demonstrate that maximally-entangled two-qubit states (Bell states) can be achieved in this scheme when complemented by proper postselection. In this situation, the time evolution of the entanglement is governed by a non-Hermitian Hamiltonian, where dynamical phases are separated by an exceptional point. The resultant Bell state is robust against weak random perturbations and does not require the preparation of a particular initial state. Our study may find applications in quantum information science, quantum spintronics, and for sensing of nonlocal quantum correlations.

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Ji Zou, Shu Zhang, Yaroslav Tserkovnyak. 2022-11-24. Bell-state generation for spin qubits via dissipative coupling. https://doi.org/10.1103/physrevb.106.l180406

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