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Publications

Search Publications by Carl J. Williams

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Displaying 26 - 50 of 151

Is Quantum Cryptography Provably Secure?

April 1, 2006
Author(s)
Anastase Nakassis, Joshua Bienfang, P. Johnson, Alan Mink, D. Rogers, Xiao Tang, Carl J. Williams
Quantum cryptography asserts that shared secrets can be established over public channels in such a way that the total information of an eavesdropper can be made arbitrarily small with probability arbitrarily close to 1. As we will show below, the current

Multichannel Quantum-Defect Theory for Slow Atomic Collisions

October 28, 2005
Author(s)
B Gao, Eite Tiesinga, Carl J. Williams, Paul S. Julienne
We present a multichannel quantum-defect theory for slow atomic collisions that takes advantages of the analytic solutions for the long-range potential, and both the energy and the angular-momentum insensitivities of the short-range parameters. The theory

High Speed Fiber-Based Quantum Key Distribution using Polarization Encoding

October 5, 2005
Author(s)
Xiao Tang, Lijun Ma, Alan Mink, Anastase Nakassis, Barry J. Hershman, Joshua Bienfang, Ronald Boisvert, Charles W. Clark, Carl J. Williams, A Gross, E Hagley, J Wen
We have implemented a quantum key distribution (QKD) system with polarization encoding at 850 nm over 1 km of optical fiber. The high-speed management of the bit-stream, generation of random numbers and processing of the sifting algorithm are all handled

High Speed Fiber-Based Quantum Key Distribution Using Polarization Encoding

October 1, 2005
Author(s)
Xiao Tang, Lijun Ma, Alan Mink, Anastase Nakassis, Barry J. Hershman, J Bienfan, Ronald Boisvert, Charles W. Clark, Carl J. Williams
The n-qubit concurrence canonical decomposition (CCD) is a generalization of the two-qubit canonical decomposition SU(4)=[SU(2) (x) SU(2)] ? [SU(2) (x) SU(2)], where ? is the commutative group which phases the maximally entangled Bell basis. A prequel

Scattering Length Determination From Trapped Pairs of Atoms

August 2, 2005
Author(s)
S Shresta, Eite Tiesinga, E L. Bolda, Carl J. Williams
A method is described for estimating effective scattering lengths via spectroscopy on a trapped pair of atoms. The method relies on the well known phenomena that the energy levels of two atoms in a harmonic trap are shifted by their collisional interaction

Scalable Register Initialization for Quantum Computing in a Optical Lattice

June 1, 2005
Author(s)
G K. Brennen, G Pupillo, A M. Rey, Charles W. Clark, Carl J. Williams
The Mott insulator state created by loading an atomic Bose-Einstein condensate (BEC) into an optical lattice may be used as a means to prepare a register of atomic qubits in an quantum computer. Such architecture requires a lattice commensurately filled

Precise Determination of 6 Li Cold Collision Parameters by Radio-Frequency Spectroscopy on Weakly Bound Molecules

March 1, 2005
Author(s)
M Bartenstein, A Altmeyer, S Riedl, R Geursen, S Jochim, C Chin, J Hecker Denschlag, R Grimm, Andrea Simoni, Eite Tiesinga, Carl J. Williams, Paul S. Julienne
Radio-frequency spectroscopy on weakly bound 6Li_2 molecules determines to high precision the molecular binding energies and the energy splitting between molecular states. By fitting the measurement to a multi-channel quantum scattering model, we determine

Feshbach Resonances in Fermionic 6 Li

January 1, 2005
Author(s)
C H. Schunck, M W. Zwierlein, C A. Stan, S M. Raupach, W Ketterle, Andrea Simoni, Eite Tiesinga, Carl J. Williams, Paul S. Julienne