A long-range entangling gate mediated by a time-bin qubit

As superconducting-qubit platforms scale up and begin to adopt modular layouts, it will become increasingly important to have a means of applying entangling gates between distant qubits. The emission and subsequent reabsorption (“pitching and catching”) of single photons has long been recognized as a useful resource for quantum state transfer and Bell-state generation in quantum networks [1-3]. We present an approach based on a time-bin encoding that would enable long-range entangling gates to be realized using a pitch-and-catch protocol. In contrast to gate teleportation, which can also be used to implement long-range gates, the approach presented here does not require ancilla Bell pairs and could therefore reduce the number of physical qubits required for distributed quantum computing.

[1] J. I. Cirac, P. Zoller, H. J. Kimble, and H. Mabuchi, Phys. Rev. Lett. 78, 3221 (1997)

[2] P. Kurpiers et al., Nature 558, 264 (2018)

[3] P. Kurpiers et al., Phys. Rev. Appl. 12, 044067 (2019)