Temporal-Mode Engineering for Multiplexed Microwave Photons and Mode-Selective Quantum State Transfer

TL;DR

This paper demonstrates the experimental generation and selective absorption of microwave photons in four orthogonal temporal modes, advancing multiplexed quantum communication and mode engineering in superconducting quantum networks.

Contribution

It introduces a photon-shaping technique for generating and selectively absorbing microwave photons in multiple temporal modes, enabling higher-dimensional quantum information encoding.

Findings

Achieved mode-selective absorption efficiencies over 0.89 for matched modes

Generated four orthogonal temporal modes of microwave photons

Showed potential for multiplexed quantum networks using temporal modes

Abstract

Quantum communication between distant superconducting qubits on separate chips using itinerant microwave photons has been studied to realize distributed quantum information processing. To enhance information capacity and fault tolerance in quantum networks, it is beneficial to encode a large quantity of quantum information using auxiliary degrees of freedom of these photons. In this work, we experimentally investigate the use of temporal modes of photon wave packets. Through the photon-shaping technique with a fixed-frequency transmon qubit, we generate single microwave photons in four orthogonal temporal modes propagating along a waveguide. We demonstrate mode-selective absorption across orthogonal modes via the time-reversed process of emission, achieving absorption efficiencies exceeding 0.89 for mode-matched cases, while remaining below 0.13 for orthogonal modes. Photons rejected by a given receiver mode can remain mutually orthogonal, enabling selective absorption at subsequent receivers in future multi-node architectures. These results highlight the feasibility of temporal-mode engineering for constructing a higher-dimensional orthogonal basis for multiplexed quantum networks.