Nonlinear feedforward enabling quantum computation

TL;DR

This paper demonstrates a fast nonlinear feedforward technique in optical quantum computing, enabling essential measurements for fault-tolerance and universality, with a 10% noise reduction using non-Gaussian states.

Contribution

It introduces a practical implementation of nonlinear feedforward in optical quantum computation, advancing towards scalable, fault-tolerant quantum computers.

Findings

Achieved 10% reduction in measurement excess noise.

Demonstrated nonlinear feedforward for fault-tolerant quantum measurement.

Enabled essential measurement for universal quantum computation.

Abstract

Measurement-based quantum computation with optical time-domain multiplexing is a promising method to realize a quantum computer from the viewpoint of scalability. Fault tolerance and universality are also realizable by preparing appropriate resource quantum states and electro-optical feedforward that is altered based on measurement results. While a linear feedforward has been realized and become a common experimental technique, nonlinear feedforward was unrealized until now. In this paper, we demonstrate that a fast and flexible nonlinear feedforward realizes the essential measurement required for fault-tolerant and universal quantum computation. Using non-Gaussian ancillary states we observed 10$\%$ reduction of the measurement excess noise relative to classical vacuum ancilla.