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: Charles W Clark (Assoc)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 76 - 100 of 447

Quantum Phases of Bosons in Double-Well Optical Lattices

October 4, 2007
Author(s)
Ippei Danshita, J G. Williams, Carlos Sa de Melo, Charles W. Clark
We study the superfluid to Mott insulator transition of bosons in a two-legged ladder optical lattice, of a type accessible in current experiments on double-well optical lattices. The zero-temperature phase diagram is mapped out, with a focus on its

Detector Dead-Time Effects and Paralyzability in High-Speed Quantum Key Distribution

September 10, 2007
Author(s)
Daniel Rogers, Joshua C. Bienfang, Anastase Nakassis, Hai Xu, Charles W. Clark
Recent advances in quantum key distribution (QKD) have given rise to systems that operate at transmission periods significantly shorter than the dead times of their component single-photon detectors. As systems continue to increase in transmission rate

Metal-Insulator Transition Revisited for Cold Atoms in Non-Abelian Gauge Potentials

November 20, 2006
Author(s)
Indubala I. Satija, D C. Dakin, Charles W. Clark
We discuss the possibility of realizing metal-insulator transitions with ultracold atoms in two-dimensional optical lattices in the presence of artificial gauge potentials. Such transitions have been extensively studied for magnetic fields corresponding to

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

Vortices in Attractive Bose-Einstein Condensates in Two Dimensions

July 7, 2006
Author(s)
L D. Carr, Charles W. Clark
The form and stability of quantum vortices in Bose-Einstein condensates with attractive atomic interactions is elucidated. They appear as ring bright solitons, and are a generalization of the Townes soliton to nonzero winding number m. An in?nite sequence

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

High Speed Quantum Key Distribution System Supports One-Time Pad Encryption of Real-Time Video

April 21, 2006
Author(s)
Alan Mink, Xiao Tang, Lijun Ma, Anastase Nakassis, Barry J. Hershman, Joshua C. Bienfang, David H. Su, Ronald F. Boisvert, Charles W. Clark, Carl J. Williams
NIST has developed a high-speed quantum key distribution (QKD) test bed incorporating both free-space and fiber systems. These systems demonstrate a major increase in the attainable rate of QKD systems: over two orders of magnitude faster than other

High Speed Quantum Key Distribution System Supports One-Time Pad Encryption of Real-Time Video

April 1, 2006
Author(s)
Alan Mink, Xiao Tang, Lijun Ma, Anastase Nakassis, Barry J. Hershman, Joshua Bienfang, David H. Su, Ronald Boisvert, Charles W. Clark, Carl J. Williams
NIST has developed a high-speed quantum key distribution (QKD) test bed incorporating both free-space and fiber systems. These systems demonstrate a major increase in the attainable rate of QKD systems: over two orders of magnitude faster than other

On the Absorption Spectrum of Noble Gases at the Arc Spectrum Limit

February 1, 2006
Author(s)
Ugo Fano, G Pupillo, A Zannoni, Charles W. Clark
Rydberg spectral lines of an atom are sometimes superimposed on the continuous spectrum of a different configuration. Effects of interaction among different configurations in one of these cases are theoretically investigated, and a formula is obtained that