Generating Haar-Uniform Randomness Using Stochastic Quantum Walks on a Photonic Chip.

Area of Science:

• Quantum Information Science
• Quantum Optics
• Quantum Computing

Background:

• Quantum operations require reliable randomness measures for tasks like boson sampling.
• The Haar measure is a standard for quantifying randomness in quantum systems.
• Previous theoretical work proposed combining quantum control and stochastic quantum walks to generate Haar-uniform randomness.

Purpose of the Study:

• To experimentally implement a protocol for generating Haar-uniform random quantum operations.
• To investigate the efficiency and scalability of using stochastic quantum walks for quantum randomness generation.
• To demonstrate the conversion of classical randomness into quantum randomness on an integrated photonic platform.

Main Methods:

• Implementation of a two-dimensional stochastic quantum walk on an integrated photonic chip.
• Analysis of distribution profiles to confirm convergence to an even distribution.
• Comparison of the convergence speed between one-dimensional and two-dimensional waveguide arrays.

Main Results:

• Experimental demonstration of convergence to 1-pad Haar-uniform randomness with increasing evolution length.
• The two-dimensional array showed faster convergence compared to a one-dimensional array with the same number of waveguides.
• Successful conversion of classical randomness into quantum randomness was achieved.

Conclusions:

• The study presents a scalable and robust method for generating Haar-uniform randomness.
• The integrated photonic implementation provides a practical approach for quantum randomness generation.
• This work offers essential building blocks for advancing quantum information technologies.