Universal Continuous Variable Quantum Computation Without Cooling

TL;DR

This paper proposes a universal continuous-variable quantum computing approach that encodes information in mixed states, eliminating the need for cooling to the ground state and enhancing noise resilience.

Contribution

It introduces a mixed-state encoding formalism and hybrid interaction-based gates, broadening the scope of continuous-variable quantum computing without cooling.

Findings

Reduces the need for cooling to the ground state.

Increases resilience to noise processes.

Lowers energy consumption during initialization.

Abstract

One of the limitations to the quantum computing capability of a continuous-variable system is determined by our ability to cool it to the ground state, because pure logical states, in which we accurately encode quantum information, are conventionally pure physical states that are constructed from the ground state. In this work, we present an alternative quantum computing formalism that encodes logical quantum information in mixed physical states. We introduce a class of mixed-state protocols that are based on a parity encoding, and propose an implementation of the universal logic gates by using realistic hybrid interactions. When comparing with the conventional pure-state protocols, our formalism could relax the necessity of, and hence the systemic requirements of cooling. Additionally, the mixed-state protocols are inherently resilient to a wider class of noise processes, and reduce the fundamental energy consumption in initialisation. Our work broadens the candidates of continuous-variable quantum computers.