Single-photon bus connecting spin-wave quantum memories

Vladan Vuletić, Jonathan Simon, Haruka Tanji +1 more

A single spin-wave quantum (magnon) is transferred phase-coherently between two atomic ensembles via a dark state of an optical resonator. Partial transfer results in an entangled state, with the magnon shared between the two ensembles.

Nunn, Langford, Champion +6 more

Tomáš Neuman, Matt Eichenfield, Matthew E. Trusheim +3 more

We introduce a method for high-fidelity quantum state transduction between a superconducting microwave qubit and the ground state spin system of a solid-state artificial atom, mediated via an acoustic bus connected by piezoelectric transducers. Applied to present-day experimental parameters for superconducting circuit qubits and diamond silicon vacancy centers in an optimized phononic cavity, we estimate quantum state transduction with fidelity exceeding 99\% at a MHz-scale bandwidth. By combining the complementary strengths of superconducting circuit quantum computing and artificial atoms, the hybrid architecture provides high-fidelity qubit gates with long-lived quantum memory, high-fidelity measurement, large qubit number, reconfigurable qubit connectivity, and high-fidelity state and gate teleportation through optical quantum networks.

Chuan‐Feng Li

Carlos, Belmonte, Vandenberghe, Frederik, Krassimir P. Panajotov +1 more

Daniel Rieländer, Andreas Lenhard, Margherita Mazzera +1 more

We report on a source of heralded narrowband ( MHz) single photons compatible with solid-state spin-wave quantum memories based on praseodymium doped crystals. Widely non-degenerate narrow-band photon pairs are generated using cavity enhanced down conversion. One photon from the pair is at telecom wavelengths and serves as heralding signal, while the heralded single photon is at 606 nm, resonant with an optical transition of Pr 3+ :Y 2 SiO 5 . The source offers a heralding efficiency of 28% and a generation rate exceeding 2000 pairs mW −1 in a single-mode. The single photon nature of the heralded field is confirmed by a direct antibunching measurement, with a measured antibunching parameter down to 0.010(4). Moreover, we investigate in detail photon cross- and autocorrelation functions proving non-classical correlations between the two photons. The results presented in this paper offer prospects for the demonstration of single photon spin-wave storage in an on-demand solid state quantum memory, heralded by a telecom photon.