On-demand generation and characterization of a microwave time-bin qubit

TL;DR

This paper demonstrates on-demand generation and phase-robust characterization of microwave time-bin qubits using superconducting circuits, enabling scalable quantum networks with simplified detection methods.

Contribution

It introduces a method for generating and performing Wigner tomography of microwave time-bin qubits with a single detector, without requiring a shared phase reference.

Findings

Successful on-demand microwave time-bin qubit generation

Wigner tomography performed with a single heterodyne detector

Demonstration of phase information conservation in time-bin qubits

Abstract

Superconducting circuits offer a scalable platform for the construction of large-scale quantum networks where information can be encoded in multiple temporal modes of propagating microwaves. Characterization of such microwave signals with a method extendable to an arbitrary number of temporal modes with a single detector and demonstration of their phase-robust nature are of great interest. Here we show the on-demand generation and Wigner tomography of a microwave time-bin qubit with superconducting circuit quantum electrodynamics architecture. We perform the tomography with a single heterodyne detector by dynamically changing the measurement quadrature with a phase-sensitive amplifier independently for the two temporal modes. By generating and measuring the qubits with hardware lacking a shared phase reference, we demonstrate conservation of phase information in each time-bin qubit generated.