Universal Quantum Computing with Arbitrary Continuous-Variable Encoding

TL;DR

This paper introduces a universal framework for quantum computing in continuous-variable systems that allows arbitrary encoding with fixed operations, simplifying hardware design and enhancing noise resilience.

Contribution

A unified formalism enabling universal quantum computation with arbitrary encoding in continuous-variable systems using fixed operations.

Findings

All computing processes implemented via basis state preparations and swap operations.

Quantum information decoupled from collective noise, improving robustness.

Potential implementation using existing continuous-variable interactions.

Abstract

Implementing a qubit quantum computer in continuous-variable systems conventionally requires the engineering of specific interactions according to the encoding basis states. In this work, we present a unified formalism to conduct universal quantum computation with a fixed set of operations but arbitrary encoding. By storing a qubit in the parity of two or four qumodes, all computing processes can be implemented by basis state preparations, continuous-variable exponential-swap operations, and swap-tests. Our formalism inherits the advantages that the quantum information is decoupled from collective noise, and logical qubits with different encodings can be brought to interact without decoding. We also propose a possible implementation of the required operations by using interactions that are available in a variety of continuous-variable systems. Our work separates the `hardware' problem of engineering quantum-computing-universal interactions, from the `software' problem of designing encodings for specific purposes. The development of quantum computer architecture could hence be simplified.