Continuous mode cooling and phonon routers for phononic quantum networks

TL;DR

This paper explores methods for quantum state transfer in phonon networks, introducing cooling schemes and phonon routers that enable efficient, magnetic-field-free quantum communication in various physical systems.

Contribution

It proposes optomechanical multi- and continuous mode cooling schemes and phonon circulators/routers that operate without strong magnetic fields, advancing phononic quantum network technology.

Findings

Cooling schemes create a 'cold' frequency window for quantum states.

Phonon circulators and routers rely solely on coherent optomechanical interactions.

Techniques are adaptable to various physical implementations with spin or charge qubits.

Abstract

We study the implementation of quantum state transfer protocols in phonon networks, where in analogy to optical networks, quantum information is transmitted through propagating phonons in extended mechanical resonator arrays or phonon waveguides. We describe how the problem of a non-vanishing thermal occupation of the phononic quantum channel can be overcome by implementing optomechanical multi- and continuous mode cooling schemes to create a 'cold' frequency window for transmitting quantum states. In addition, we discuss the implementation of phonon circulators and switchable phonon routers, which rely on strong coherent optomechanical interactions only, and do not require strong magnetic fields or specific materials. Both techniques can be applied and adapted to various physical implementations, where phonons coupled to spin or charge based qubits are used for on-chip networking applications.