This is a Continuation of Grant N000141310627 - Fundamental research on wavelength agile high-rate quantum key distribution (QKD) in a marine environment
Abstract
Key scientific questions to be investigated include how is the security of the QKD system optimized by the choice and number of Hilbert space dimensions and number of mutually unbiased bases, when one accounts for non-ideal effects, e.g., dark counts, quantum statistics of entangled pairs, quickly varying background, etc.; are the classical Optical Code Division Multiple Access (OCDMA) codes optimal for the case when one requires true quantum cryptographic security; what wavelength is optimal for a given free-space link under various conditions of turbulence, daylight, aerosol concentration, fog, etc.; can a single detector technology enable high-efficiency low-noise detection over the required ranges of wavelength, can practical arrays be realized; is turbulence more effectively dealt with by pre- or post-compensation (using a classical beacon, wavefront sensor and adaptive optics (AO)), or by using the classically measured signal to post-select particular quantum channels (requiring no AO, but single-photon detector arrays); what is the secure capacity of an array of N parallel QKD channels? Does the existence of channel correlations and MIMO-like coding strategies result in capacity enhancement factors; what are the tradeoffs in using nonlocality tests at both Alice?s and Bob?s stations (to remove dependence on channel loss) to verify the sources and receivers, a la device-independent QKD.They propose a comprehensive, basic science investigation of agile free-space QKD strategies that can automatically adjust for optimal performance in the highly variable environment encountered over the sea deck and can operate at secure rates exceeding 100 Mb/s. They will pursue complementary approaches, undertaking fundamental studies of QKD systems that use (hyper-)entangled photon pairs or weak coherent states (WCS) as the quantum resources. Their QKD protocols will encode information in a high-dimensional Hilbert space, using generalized time-energy (equivalently, time-frequency) states optimized for high-speed, where security measurements can be performed in real time, and there exist approaches for error correction, which will be optimized for speed and efficiency. Such time-energy states are less fragile to disturbance in a complex time-varying free-space channel than, e.g., spatial-mode encoding.The primary protocol uses the time-frequency quantum data hypercube.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 21, 2018
- Source ID
- N000141612238
Entities
People
- Paul G. Kwiat
Organizations
- Office of Naval Research
- United States Navy
- University of Illinois Urbana–Champaign