Topological protection of biphoton states

Protecting entangled peers

Photons are simply produced, and are ideal carriers of quantum information. Practical applications, such as quantum computing, will likely be based on an optical-chip platform and require the manipulation of multiphoton states. The inevitable scattering and loss of photons in such a platform would be detrimental for application. Blanco Redondo et al. Dedicated to the protection of propagating biphoton states. The results show that it is possible to obtain the desired robustness required for quantum optical circuitry.

Science, this issue p. 568

Abstract

The robust generation and propagation of multiphoton quantum states are crucial for applications in quantum information, computing, and communications. Although photons are intrinsically well isolated from the thermal environment, scaling to large quantum optical devices is still limited by scattering and other errors arising from random manufacturing imperfections. The recent discoveries regarding topological phases have been introduced to construct quantum systems that are protected against scattering and imperfections. We are experimentally demonstrating topological protection of biphoton states, the building block for quantum information systems. We provide clear evidence of the robustness of the spatial features and the constant propagation of biphoton states generated within a nanophotonics lattice with nontrivial topology and offers a robust path to robust entangled states for quantum gates.