Deterministic generation of shaped single microwave photons using a parametrically driven coupler

TL;DR

This paper demonstrates a superconducting circuit that deterministically transfers quantum states into shaped microwave photons with high fidelity, enabling reliable quantum communication between distributed quantum processors.

Contribution

It introduces a method using a parametric drive to shape microwave photons for improved quantum state transfer in superconducting circuits.

Findings

Achieved a process fidelity of 94.5% in state transfer.

Implemented a self-calibrating routine for frequency shifts.

Shaped photons are time-symmetric with constant phase for reabsorption.

Abstract

A distributed quantum computing system requires a quantum communication channel between spatially separated processing units. In superconducting circuits, such a channel can be realized by using propagating microwave photons to encode and transfer quantum information between an emitter and a receiver node. Here we experimentally demonstrate a superconducting circuit that deterministically transfers the state of a data qubit into a propagating microwave mode, with a process fidelity of 94.5%. We use a time-varying parametric drive to shape the temporal profile of the propagating mode to be time-symmetric and with constant phase, so that reabsorption by the receiving processor can be implemented as a time-reversed version of the emission. We demonstrate a self-calibrating routine to correct for time-dependent shifts of the emitted frequencies due to the modulation of the parametric drive. Our work provides a reliable method to implement high-fidelity quantum state transfer and remote entanglement operations in a distributed quantum computing network.