Enhancing quantum cryptography with quantum dot single-photon sources

Abstract

Quantum cryptography harnesses quantum light, in particular single photons, to provide security guarantees that cannot be reached by classical means. For each cryptographic task, the security feature of interest is directly related to the photons’ non-classical properties. Quantum dot-based single-photon sources are remarkable candidates, as they can in principle emit deterministically, with high brightness and low multiphoton contribution. Here, we show that these sources provide additional security benefits, thanks to the tunability of coherence in the emitted photon-number states. We identify the optimal optical pumping scheme for the main quantum-cryptographic primitives, and benchmark their performance with respect to Poisson-distributed sources such as attenuated laser states and down-conversion sources. In particular, we elaborate on the advantage of using phonon-assisted and two-photon excitation rather than resonant excitation for quantum key distribution and other primitives. The presented results will guide future developments in solid-state and quantum information science for photon sources that are tailored to quantum communication tasks.

Room Temperature Fiber-Coupled single-photon devices based on Colloidal Quantum Dots and SiV centers in Back Excited Nanoantennas

“…Such on-chip RT single-photon devices with high CE are very appealing for compact integration into free space and fiber based quantum communication systems. 26,[48][49][50][51][52][53] We also demonstrated the applicability of highly accurate positioning methods of nano-emitters for complex device fabrication: for NDs containing SiV-centers, we utilized a pick and place method, which is highly accurate and enables multi-stage position optimization and dipole rotation optimization. 54 For the QDs placing, we utilized a DPN technique, which is amenable to scaling and is highly accurate.…”

Quantum Authentication Method based on Key-Controlled Maximally Mixed Quantum State Encryption

“…Quantum authentication schemes based on entangled states, such as the Bell or GHZ states, are difficult to generate and maintain [34][35][36]; our schemes using single qubits are feasible and efficient for implementation. In addition, our schemes are easy to implement because they perform a single quantum operation.…”

Epitaxial quantum dots: a semiconductor launchpad for photonic quantum technologies

“…The entangled photon pairs created by quantum dots are also valuable resources for quantum cryptography [260,277–281] , especially because the entanglement creation process can be deterministic, the entanglement fidelity can be near-unity, and multi-photon error is typically low. In recent demonstrations, one photon from the entangled pair is distributed to a close-by station; the other one is sent to a remote station several hundreds of meters apart via either free-space transmission or low-loss fibers.…”