Indistinguishable photons play a crucial role in quantum technologies

Indistinguishable photons are an integral part of many quantum applications. Lal et al. review the concept of indistinguishability, its significance in quantum information processing, and experimental techniques of quantification. The review also includes a detailed literature survey of the state-of-the-art technology.

The study and quantification of photon indistinguishability is foundational in photon-based information processing, specifically in the areas of quantum logic gates and quantum communication. Potential applications include the secure transfer of information, quantum computation, photonic boson sampling, quantum cryptology, quantum information processing, and quantum metrology.

“Indistinguishable photons are headed to play a crucial role in amplifying laboratory quantum protocols on a global scale,” said author Nijil Lal.

Correlations between indistinguishability and other behaviors, such as photon entanglement, interference, and quantum erasure are presented along with methods used to quantify indistinguishability. The authors also discuss the efficient production of indistinguishable single photons via non-linear crystal-based and solid-state sources.

The authors believe this review will be helpful to researchers working in the field of optical quantum communication, as well as students of quantum technologies. These researchers will continue to focus on developing sources for photon indistinguishability without sacrificing optimized photon efficiency and entanglement fidelity.

“With its major applications, such as quantum communications and quantum computing, being hot topics of the day, the research on improved indistinguishability of photons has become the need of the hour,” said Lal.

Source: “Indistinguishable photons,” by Nijil Lal, Sarika Mishra, and R. P. Singh, AVS Quantum Science (2022). The article can be accessed at https://doi.org/10.1116/5.0083968 .