U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by:

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 26 - 50 of 302

Experimental Study of High Speed Polarization -Coding Quantum Key Distribution with Sifted -Key Rates Over Mbit/s

June 1, 2009
Author(s)
Xiao Tang, Lijun Ma, Alan Mink, Anastase Nakassis, Barry J. Hershman, Joshua C. Bienfang, David H. Su, Ronald F. Boisvert, Charles W. Clark, Carl J. Williams
We have demonstrated a polarization encoded, fiber-based quantum key distribution system operating at 850 nm in the B92 protocol. With a quantum bit transmission rate i.e. optical pulse driving frequency of 625 MHz and a mean photon number of 0.1, we

Is Quantum Cryptography Provably Secure?

June 1, 2009
Author(s)
Anastase Nakassis, Joshua C. Bienfang, Paul M. Johnson, Alan Mink, D J. 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

Quantum Key Distribution System Operating at Sifted-Key Rate Over 4 Mbit/s 1

June 1, 2009
Author(s)
Xiao Tang, Lijun Ma, Alan Mink, Anastase Nakassis, Hai Xu, Barry J. Hershman, Joshua C. Bienfang, David H. Su, Ronald F. Boisvert, Charles W. Clark, Carl J. Williams
A complete fiber-based polarization encoding quantum key distribution (QKD) system based on the BB84 protocol has been developed at National Institute of Standard and Technology (NIST). The system can be operated at a sifted key rate of more than 4 Mbit/s

Perfect Quantum State Transfer With Superconducting Phase Qubits

October 16, 2008
Author(s)
Frederick Strauch, Carl J. Williams
Superconducting quantum circuits, fabricated with multiple layers, are proposed to implement perfect quantum state transfer between nodes of a hypercube network. For tunable devices such as the phase qubit, each node can transmit quantum information to any

Vortices, Antivortices and Superfluid Shells Separating Mott-Insulating Regions

October 16, 2008
Author(s)
Kaushik Mitra, Carl J. Williams, Carlos Sa de Melo
Atomic or molecular bosons in harmonically confined optical lattices are found to exhibit a wedding cake structure consisting of insulating (Mott) and superfluid shells. It is found that the order parameter equation in the superfluid regions is not of the

Population-imbalanced fermions in harmonically trapped optical lattices

July 21, 2008
Author(s)
Menderes Iskin, Carl J. Williams
The attractive Fermi-Hubbard Hamiltonian is solved via the Bogoliubov-de Gennes formalism to analyze the ground state phases of population imbalanced fermion mixtures in harmonically trapped two-dimensional optical lattices. In the low density limit the

Pseudo-Fermionization of 1-D Bosons in Optical Lattices

February 2, 2008
Author(s)
G Pupillo, A M. Rey, Carl J. Williams, Charles W. Clark
We present a model that generalizes the Bose-Fermi mapping for strongly correlated 1D bosons in an optical lattice, to cases in which the average number of atoms per site is larger than one. This model gives an accurate account of equilibrium properties of

Trap-Imbalanced Fermion Mixtures

January 7, 2008
Author(s)
Menderes Iskin, Carl J. Williams
We analyze the ground state phases of two-component population- andmass-balanced but trap-imbalanced fermion mixtures as a function of interactionstrength from the weak attraction Bardeen-Cooper-Schrieffer (BCS) to the strongattraction Bose-Einstein

Manipulation of the Collisional Frequency Shift in Caesium Fountain Clocks

September 13, 2007
Author(s)
K Szymaniec, W Chalupczak, S Weyers, R. Wynands, Eite Tiesinga, Carl J. Williams
The frequency shift due to atomic collisions is a major, and in some cases the dominant, limitation to the accuracy of caesium fountain primary frequency standards. A correction for this shift is usually obtained by measuring the frequency of the standard

Cancellation of the Collisional Frequency Shift in Caesium Fountain Clocks

April 13, 2007
Author(s)
K Szymaniec, W Chalupczak, Eite Tiesinga, Carl J. Williams, S Weyers, R. Wynands
We have observed that the collisional frequency shift in primary caesium fountain clocks varies with the clock state population composition and, in particular, is zero for a given fraction of the |F = 4, mF = 0> atoms, depending on the initial cloud

Demonstration of an Active Quantum Key Distribution Network

August 1, 2006
Author(s)
Xiao Tang, Lijun Ma, Alan Mink, Anastase Nakassis, Hai Xu, Barry J. Hershman, Joshua Bienfang, David H. Su, Ronald Boisvert, Charles W. Clark, Carl J. Williams
We previously demonstrated a high speed, point to point, quantum key distribution (QKD) system with polariztion coding over a fiber link, in which the resulting cryptographic keys were used for one-time pad encryption of real time video signals. In this

Quantum Key Distribution System Operating at Sifted-Key Rate over 4 Mbit/s

June 19, 2006
Author(s)
Xiao Tang, Lijun Ma, Alan Mink, Anastase Nakassis, Hai Xu, Barry J. Hershman, Joshua Bienfang, David H. Su, Ronald Boisvert, Charles W. Clark, Carl J. Williams
A complete fiber-based polarization encoding quantum key distribution (QKD) system based on the BB84 protocol has been developed at National Institute of Standard and Technology (NIST). The system can be operated at a sifted key rate of more than 4 Mbit/s
Was this page helpful?