Realization of a second-generation scheme for dissipative entanglement of hyperfine beryllium-ion qubits

The generation of entanglement using engineered dissipation has recently attracted attention because this approach can be competitive in fidelity and robustness against noise when compared with methods of entanglement generation based on controlled unitary evolution, and can enable optical pumping directly into entangled resource states for quantum protocols [1]. In a dissipative entanglement generation scheme, population is trapped in a target entangled state through evolution according to dissipative dynamics that have the target state as a steady state. We will discuss the generation of entangled states of hyperfine beryllium-ion qubits using engineered dissipation. In particular, we will present experimental realization of a ‘second generation’ scheme for dissipative production of an entangled singlet state that offers an improvement in speed and fidelity, along with reduced experimental complexity [2]. This scheme involves engineering suitable spin-motion couplings in the Hamiltonian, which are then combined with dissipation in the form of pumping to and decay from an electronic excited state.

[1] Y. Lin et al., Nature 504, 415 (2013).
[2] K. Horn et al., New J. Phys. 20, 123010 (2018).