Quantum simulation of topologically protected states using directionally unbiased linear-optical multiports

TL;DR

This paper demonstrates how linear-optical multiports can simulate topologically protected states in quantum systems, specifically using a modified SSH model, with resource efficiency and potential for higher-dimensional generalizations.

Contribution

It introduces a novel linear-optical setup for simulating topological phases, reducing resource requirements and enabling higher-dimensional topological quantum simulations.

Findings

Successfully simulates topological boundary states in optical systems

Uses quadratically fewer resources than previous methods

Can be extended to higher-dimensional topological models

Abstract

It is shown that quantum walks on one-dimensional arrays of special linear-optical units allow the simulation of discrete-time Hamiltonian systems with distinct topological phases. In particular, a slightly modified version of the Su-Schrieffer-Heeger (SSH) system can be simulated, which exhibits states of nonzero winding number and has topologically protected boundary states. In the large-system limit this approach uses quadratically fewer resources to carry out quantum simulations than previous linear-optical approaches and can be readily generalized to higher-dimensional systems. The basic optical units that implement this simulation consist of combinations of optical multiports that allow photons to reverse direction.