Universal unitary transfer of continuous-variable quantum states into a few qubits

TL;DR

This paper introduces a deterministic protocol for transferring continuous-variable quantum states into a few qubits using two-mode Rabi interactions, with exponential error suppression and noise robustness, enabling hybrid quantum systems.

Contribution

It presents a novel, practical method for universal state transfer between continuous and discrete quantum systems, compatible with existing platforms.

Findings

Error suppression increases exponentially with the number of qubits

Encoded states are robust against noise such as dephasing and damping

Protocol is compatible with trapped-ion and superconducting circuits

Abstract

We present a protocol for transferring arbitrary continuous-variable quantum states into a few discrete-variable qubits and back. The protocol is deterministic and utilizes only two-mode Rabi-type interactions which are readily available in trapped-ion and superconducting circuit platforms. The inevitable errors caused by transferring an infinite-dimensional state into a finite-dimensional register are suppressed exponentially with the number of qubits. Furthermore, the encoded states exhibit robustness against noise, such as dephasing and amplitude damping, acting on the qubits. Our protocol thus provides a powerful and flexible tool for discrete-continuous hybrid quantum systems.