# Arbitrary multimode Gaussian operations on mechanical cluster states

## TL;DR

This paper demonstrates that opto- and electro-mechanical systems can perform universal Gaussian quantum computation through indirect measurements, achieving high fidelity within current experimental capabilities.

## Contribution

It introduces a method for implementing arbitrary Gaussian MBQC in mechanical systems via indirect measurements, bypassing the need for direct measurements on mechanical resonators.

## Key findings

- High fidelity indirect measurements are feasible with current technology.
- Mechanical cluster states can be used for universal quantum computation.
- Performance analysis shows comparable results to direct measurement schemes.

## Abstract

We consider opto- and electro-mechanical quantum systems composed of a driven cavity mode interacting with a set of mechanical resonators. It has been proposed that the latter can be initialized in arbitrary cluster states, including universal resource states for Measurement Based Quantum Computation (MBQC). We show that, despite the unavailability in this set-up of direct measurements over the mechanical resonators, computation can still be performed to a high degree of accuracy. In particular, it is possible to indirectly implement the measurements necessary for arbitrary Gaussian MBQC by properly coupling the mechanical resonators to the cavity field and continuously monitoring the leakage of the latter. We provide a thorough theoretical analysis of the performances obtained via indirect measurements, comparing them with what is achievable when direct measurements are instead available. We show that high levels of fidelity are attainable in parameter regimes within reach of present experimental capabilities.