AMO SEMINAR

Antia Lamas-Linares, NIST

"Making and breaking quantum cryptography"

4:00pm, RLM 5.104

Abstract:

Quantum key distribution (QKD) holds the promise of providing a method to send secret messages garantied by the laws of physics. Recent experiments have shown that underlying assumptions about the functioning of single photon detectors led to a fundamental security flaw. I will describe a typical QKD experiment based on entangled photons and how we were able to silently eavesdrop and extract 100% of the "secret" key. However, this is not the the last word for QKD. The tests to rule out local realism in the form of Bell inequalities can also provide a path to "ultimate" security in QKD, as long as the tests are complete or loophole-free. While no complete, loophole-free test has been performed yet, very fast progress is being made in that direction. I will describe some recent work on superconducting single photon detectors that are likely to be part of the next generation of Bell inequality tests.