Multi-qubit quantum state preparation enabled by topology optimization

TL;DR

This paper demonstrates how topology optimization can be used to design nanophotonic cavities that efficiently prepare high-fidelity multiqubit quantum states, advancing quantum information processing capabilities.

Contribution

It introduces a novel inverse-design approach using topology optimization to create nanophotonic devices for high-fidelity multiqubit state preparation.

Findings

Achieved near-unity fidelity for Bell and W states in distant qubits.

Generated entanglement by maximizing dissipative coupling.

Enabled efficient preparation of multiqubit quantum states.

Abstract

Using topology optimization, we inverse-design nanophotonic cavities enabling the preparation of pure states of pairs and triples of quantum emitters. Our devices involve moderate values of the dielectric constant, operate under continuous laser driving, and yield fidelities to the target (Bell and W) states approaching unity for distant qubits (several natural wavelengths apart). In the fidelity optimization procedure, our algorithm generates entanglement by maximizing the dissipative coupling between the emitters, which allows the formation of multipartite pure steady states in the driven-dissipative dynamics of the system. Our findings open the way towards the efficient and fast preparation of multiqubit quantum states with engineered features, with potential applications for nonclassical light generation, quantum simulation, and quantum sensing.