# Simulating the Dynamics of Single Photons in BosonSampling Devices with Matrix Product States

## TL;DR

This paper demonstrates how matrix product states can be used to simulate and analyze the quantum dynamics of photons in BosonSampling devices, revealing entanglement growth and extending to dissipative and fermionic systems.

## Contribution

It introduces a novel application of matrix product states to simulate photon dynamics in BosonSampling, including dissipative and fermionic circuits, enhancing understanding of quantum interference.

## Key findings

- Matrix product states effectively simulate photon evolution in BosonSampling.
- The method reveals entanglement entropy growth during photon dynamics.
- Applicable to dissipative and fermionic quantum circuits.

## Abstract

BosonSampling is a well-defined scheme for demonstrating quantum supremacy with photons in near term. Although relying only on multi-photon interference in nonadaptive linear-optical networks, it is hard to simulate classically. Here we study BosonSampling using matrix product states, a powerful method from quantum many-body physics. This method stores the instantaneous quantum state during the evolution of photons in the optical quantum circuit, which allows us to reveal the dynamical features of single photons in BosonSampling devices, such as entanglement entropy growth. We show the flexiblility of this method by also applying it to dissipative optical quantum circuits, as well as circuits with fermionic particles. Our work shows that matrix product states is a powerful platform to simulate optical quantum circuits. And it is readily extended to study quantum dynamics in multi-particle quantum walks beyond BosonSampling.