Quantum key distribution using sequential weak values

Abstract

We propose a new secure key distribution method that utilizes the properties of the sequential weak values of a quantum observable to prevent eavesdropping. Unlike all previous protocols, the security of this QKD protocol does not rely on the no-cloning theorem or on the spatial nonlocality of entangled states. The robustness of the protocol to detector dark counts and optical losses is investigated and is found to compare favorably with BB84. While this new protocol has the drawback of a very low secure key generation rate, that the rate is non-zero is a significant result due to the lack of any obvious use of the usual resources of quantum information.

On the power of weak measurements in separating quantum states

“…Including an additional linear transformation in the scheme we can generalized it to the case of two states chosen from two different mutually unbiased bases. This scheme might be suitable for quantum cryptography, and indeed, very recently a method based on sequential weak measurements was suggested for secure key distribution [33].…”