Quantum randomness certification with untrusted measurements and few probe states

TL;DR

This paper introduces an experimentally feasible quantum random-number generation scheme that certifies randomness with untrusted measurement devices and minimal trusted probe states, robust against noise and imperfections.

Contribution

It provides a practical protocol for quantum randomness certification that requires only a few trusted states and no assumptions about measurement noise, demonstrated with homodyne detection.

Findings

Successfully certified randomness with untrusted measurements.

Demonstrated implementation using homodyne detection of vacuum states.

Proved robustness against Gaussian and non-Gaussian noise.

Abstract

We present a scheme for quantum random-number generation from an untrusted measurement device and a trusted source and demonstrate it experimentally. No assumptions about noise or imperfections in the measurement are required, and the scheme is simple to implement with existing technology. The measurement device is probed with a few trusted states and the output entropy can be lower bounded conditioned on the observed outcome distribution. The protocol can be applied to measurements with any finite number of outcomes and in particular can be realised by homodyne measurements of the vacuum using a detector probed by coherent states, as we experimentally demonstrate by intensity modulation of a telecom-wavelength pilot laser followed by homodyne detection and discretisation by analog-to-digital conversion. We show that randomness can be certified in the presence of both Gaussian additive noise and non-Gaussian imperfections.