A team of physicists at the Hebrew University of Jerusalem’s Racah Institute of Physics, in collaboration with scientists from Los Alamos National Laboratory, has developed a new approach for quantum encryption. The research, published in PRX Quantum, introduces a practical solution for quantum key distribution (QKD) that is designed to work with imperfect light sources, addressing a challenge of building ideal single-photon sources.
The team, which includes PhD students Yuval Bloom and Yoad Ordan, developed two new protocols: a truncated decoy state protocol and a heralded purification protocol. These protocols were applied to sub-Poissonian photon sources based on quantum dots. Simulations and laboratory experiments demonstrated that these protocols outperform traditional laser-based QKD approaches, extending secure key distribution by more than three decibels. To validate their innovation, the team built an operational quantum communication system using a room-temperature quantum dot source and implemented a reinforced version of the BB84 protocol.
The research demonstrates that effective QKD can be achieved without relying on perfectly engineered hardware, with the goal of reducing costs and technical barriers to large-scale quantum-secure communication. The protocols can be used with a wide range of quantum light sources. Professor Ronen Rapaport commented that the work shows that superior performance can be achieved with current hardware by using inventive protocols.
Read the full announcement here and the paper in PRX Quantum here.
September 4, 2025
