Generation of a microwave time-bin qubit with a superconducting qubit

Quantum information can be encoded in a propagating photonic qubit by constructing a set of computational basis states with one or more modes of light. This encoding scheme defines the characteristic properties of the qubit such as its decoherence properties and how it retains phase information. By encoding the qubit in a basis constructed from two orthogonal temporal modes, as a time-bin qubit, it is possible to detect and correct photon decay during information transfer with a parity measurement.
We experimentally demonstrate a protocol for deterministic on-demand generation of a time-bin qubit in the microwave regime through microwave-driven coherent control of a transmon qubit placed in a three-dimensional cavity. To perform quantum state tomography on a prepared time-bin qubit state, we apply iterative maximum likelihood estimation on time-bin encoded single-photon signal squeezed in different quadratures. We also discuss different factors affecting the time-bin qubit state preparation fidelity. Our protocol can be used as a means of realizing robust information transfer in quantum networks.