# Simple source device-independent continuous-variable quantum random number generator

## TL;DR

This paper presents a practical, high-speed quantum random number generator using phase-randomized optical homodyne detection that does not require active optical components, making it suitable for compact and certified randomness sources.

## Contribution

It introduces a source-device-independent quantum random number generator leveraging phase-randomized homodyne detection with a gain-switched laser, simplifying implementation for practical use.

## Key findings

- Achieved a random number generation rate of 270 Mbit/s.
- Demonstrated a device-independent approach without active optical components.
- Provided a proof-of-principle implementation suitable for compact applications.

## Abstract

Phase-randomized optical homodyne detection is a well-known technique for performing quantum state tomography. So far, it has been mainly considered a sophisticated tool for laboratory experiments but unsuitable for practical applications. In this work, we change the perspective and employ this technique to set up a practical continuous-variable quantum random number generator. We exploit a phase-randomized local oscillator realized with a gain-switched laser to bound the min-entropy and extract true randomness from a completely uncharacterized input, potentially controlled by a malicious adversary. Our proof-of-principle implementation achieves an equivalent rate of 270 Mbit/s. In contrast to other source-device-independent quantum random number generators, the one presented herein does not require additional active optical components, thus representing a viable solution for future compact, modulator-free, certified generators of randomness.