Advanced Quantum Communication Protocols
Final rept. 18 Aug 2003-17 Dec 2005
ILLINOIS UNIV CHAMPAIGN GRANTS AND CONTRACT ADMINISTRATION
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We have realized the first demonstration of relativistic quantum cryptography, using both faint laser pulses and entangled photons. By incorporating an optical delay cavity, Bob is able to measure every photon from Alice in the correct basis, leading to enhanced key rates, as well as some security advantages. We have also implemented our proposal for a high-speed quantum random number generator, in which the arrival time of a detected photon is used to generate -8 random bits per photon. Our system produced cryptographically secure bits at over 4 Mbitss, with a clear path toward even higher rates. In addition, we solved a number of technical problems to produce 99-fidelity polarization-entangled pairs from a diode-laser pumped source. Extending our previous implementation of remote state preparation, we have incorporated hyperentanglement to successfully remotely prepare entangled states. Finally, we studied the use of hyperentangled photons as a resource for improved quantum dense coding. Although our experimental verification is still in progress, we identified the theoretically optimal configuration, and compared hyperentangled and multi-pair encoding.
- Computer Programming and Software
- Quantum Theory and Relativity