Dr. Howard E. Brandt U.S. Army Research Laboratory (ARL) An Isaac Newton Institute Workshop Entanglement and Transfer of Quantum Information Quantum Cryptographic Probing by Entanglement 27 September – 1 October 2004

1= 0= 1= 0= Binary Encoding in Photon Linear-Polarization States for BB84 Protocol      

General Entangling Probe Probe interacts unitarily with signal on its way from transmitter to legitimate receiver and is projectively measured after signal is projectively measured by legitimate receiver. M Probe Measuring Device Probe Transmitter Receiver U

(two-dimensional probe) (four-dimensional probe)

Entangling Probe Schematic CNOT gate (cavity QED / solid state / ?) probe photon incident signal state gated probe photon gated signal photon delay switch Wollaston Prism

H. E. Brandt, “Optimum probe parameters for entangling probe in quantum key distribution,” Quantum Information Processing 2, (2003). H. E. Brandt, “Optimization problem in quantum cryptography,” J. Optics B 5, S1-4 (2003). H. E. Brandt, “Quantum measurement with a positive operator valued measure”, J. Optics B 5, S (2003). H. E. Brandt, “Probe optimization in four-state protocol of quantum cryptography,” Phys. Rev. A 66, (16) (2002). H. E. Brandt, “Secrecy capacity in the four-state protocol of quantum key distribution,” J. Math. Phys. 43, (2002). H. E. Brandt, “Inconclusive rate with a positive operator valued measure,” Contemp. Math. 305, (2002). H. E. Brandt, “Qubit Devices,” Proc. Sympos. Appl. Math. 58, (2002). H. E. Brandt, “Deconstructing Wigner’s density matrix concerning the mind-body question,” Found. Phys. Lett. 15, (2002). Selected Refereed Publications on Quantum Information Processing

H. E. Brandt, “Inconclusive rate in quantum key distribution,” Phys. Rev. A 64, (5) (2001). H. E. Brandt, “Inconclusive rate as a disturbance measure in quantum cryptography,” Phys. Rev. A 62, (14) (2000). H. E. Brandt, “Eavesdropping optimization for quantum cryptography using a positive operator-valued measure,” Phys. Rev. A 59, (1999). H. E. Brandt, “Positive operator valued measure in quantum information processing,” Am. J. Phys. 67, (1999). H. E. Brandt, “Qubit devices and the issue of quantum decoherence,” Prog. Quantum Electronics 22, (1998). H. E. Brandt, “Quantum decoherence in qubit devices,” Opt. Eng. 37, (1998). H. E. Brandt, J. Myers, S. Lomonaco, “Aspects of entangled translucent eavesdropping in quantum cryptography,” Phys. Rev. A 56, (1997). J. Myers, H. E. Brandt, “Converting a positive operator-valued measure to a design for a measuring instrument on the laboratory bench,” Meas. Sci. Technol. 8, (1997). Selected Refereed Publications on Quantum Information Processing (cont.)