Towards Bell-state stabilization using the Very Small Logical Qubit (VSLQ) device: Part I

Preparing and stabilizing entangled states is critical to many quantum information tasks, including autonomous quantum error correction. Inspired by previous dissipation-engineering schemes[1,2], we propose an autonomous protocol that prepares and stabilizes an arbitrary Bell state between a pair of superconducting qubits. This is achieved by parametrically coupling the superconducting qubits to each other, and to two dissipative baths that are made of low-Q resonators. The parametric couplings are engineered through the dynamical modulation of the qubit-qubit and the qubit-cavity interaction strengths at three different frequencies with appropriate phases. Numerical simulation shows that high fidelities of >95% are reached for all the Bell states, under realistic circuit parameters well-achievable by current circuit-QED technology. We further demonstrate how this scheme is fully compatible and can be experimentally realized on the VSLQ circuit[1].
[1] E. Kapit. Phys. Rev. Lett.116, 150501 (2016)
[2] Y. Lu et al. Phys. Rev. Lett. 119, 150502 (2017)