Multi-bit quantum random number generator from a single qubit quantum walk

TL;DR

This paper introduces a method for generating multiple random bits from a single qubit using a one-dimensional quantum walk, leveraging quantum interference and entanglement to ensure high randomness in a single measurement.

Contribution

It demonstrates a novel scheme for multi-bit quantum random number generation from a single qubit via discrete-time quantum walks, highlighting practical applications in quantum cryptography.

Findings

High randomness certified regardless of initial qubit state

Generation of (l+2)-bit random strings from a single measurement

Potential for extension to higher-dimensional quantum walks

Abstract

We present a scheme for multi-bit quantum random number generation using a single qubit discrete-time quantum walk in one-dimensional space. Irrespective of the initial state of the qubit, quantum interference and entanglement of particle with the position space in the walk dynamics certifies high randomness in the system. Quantum walk in a position space of dimension $2^l+1$ ensures string of $(l+ 2)$-bits of random numbers from a single measurement. Bit commitment with the position space and control over the spread of the probability distribution in position space enable us with options to extract multi-bit random numbers. This highlights the {\it power of one qubit} , its practical importance in generating multi-bit string in single measurement and the role it can play in quantum communication and cryptographic protocols. This can be further extended with quantum walks in higher dimensions.