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Search Publications by: Stephen Eckel (Fed)

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Displaying 76 - 94 of 94

A supersonically expanding Bose-Einstein condensate: an expanding universe in the lab

April 19, 2018
Author(s)
Stephen P. Eckel, Avinash Kumar, Theodore Jacobson, Ian B. Spielman, Gretchen K. Campbell
We study the dynamics of a supersonically expanding Bose-Einstein ring condensate both experimentally and theoretically using simulations. Such expansion shows a redshift of long-wavelength excitations, similar to those seen in the standard cosmological

Vacuum Furnace for Degassing Stainless-Steel Vacuum Components

March 1, 2018
Author(s)
James A. Fedchak, Julia K. Scherschligt, Daniel S. Barker, Stephen P. Eckel, Alex P. Farrell, Makfir Sefa
Ultra-high vacuum systems must often be constructed of materials with ultra-low outgassing rates to achieve pressure of 10-6 Pa and below. In such a case, any component placed into the ultra-high vacuum system must also be constructed of materials with

Development of a new UHV/XHV pressure standard (Cold Atom Vacuum Standard)

November 10, 2017
Author(s)
Julia Scherschligt, James A. Fedchak, Daniel Barker, Stephen Eckel, Nikolai Klimov, Constantinos Makrides, Eite Tiesinga
The National Institute of Standards and Technology has recently begun a program to develop a primary pressure standard that is based on ultra-cold atoms, covering a pressure range of 1 × 10-6 Pa to 1 × 10-10 Pa and possibly lower. These pressures

Perspectives for a new realization of the pascal by optical methods

October 24, 2017
Author(s)
Jay H. Hendricks, Karl Jousten, Jack A. Stone Jr., Patrick F. Egan, Tom Rubin, Christof Gaiser, Rene Schodel, James A. Fedchak, Jacob E. Ricker, Jens Fluegge, Stephen P. Eckel, Julia K. Scherschligt, Daniel S. Barker, Kevin O. Douglass, Gregory F. Strouse, Uwe Sterr, Waldimir Sabuga
Since the beginning of measurement of pressure in the 17th century, the unit of pressure has been defined by the relationship of force per unit area. The present state of optical technology now offers the possibility of using a thermodynamic definition

Contact resistance and phase slips in mesoscopic superfluid atom transport

June 15, 2016
Author(s)
Stephen Eckel, Jeffrey Lee, Fred Jendrejewski, Christopher Lobb, Gretchen K. Campbell, Wendell Hill
We have experimentally measured both resistive flow and superflow with bosonic atoms in a mesoscopic transport experiment. Our system, consisting of two Bose-Einstein condensates coupled by a narrow channel, shows resistive flow for currents above a

Minimally destructive, Doppler measurement of a quantized, superfluid flow

February 1, 2016
Author(s)
Avinash Kumar, Neil Anderson, William D. Phillips, Stephen P. Eckel, Gretchen K. Campbell, Sandro Stringari
The Doppler effect, the shift in the frequency of sound due to motion, is present in both classical gases and quantum superfluids. Here, we perform an in-situ, minimally destructive measurement, of the persistent current in a ring-shaped, superfluid Bose

Interferometric Measurement of the Current-Phase Relationship of a Superfluid Weak Link

September 22, 2014
Author(s)
Stephen Eckel, Fred Jendrzejewski, Avinash Kumar, Christopher J. Lobb, Gretchen K. Campbell
Weak connections between superconductors or superfluids differ from classical links due to quantum coherence, which allows flow without resistance. Transport properties through such weak links can be described with a single function, the current-phase

Resistive Flow in a Weakly Interacting Bose-Einstein condensate

July 25, 2014
Author(s)
Fred Jendrzejewski, Stephen P. Eckel, Noel Murray, Calib Lanier, Mark Edwards, Christopher J. Lobb, Gretchen K. Campbell
We report the direct observation of resistive flow through a weak link in a weakly interacting atomic Bose- Einstein condensate (BEC). Two weak links separate our ring-shaped superfluid atomtronic circuit into two distinct regions, a source and a drain

Hysteresis in Quantized Superfluid Atomtronic Circuit

February 14, 2014
Author(s)
Stephen P. Eckel, Jeffrey Lee, Fred Jendrzejewski, Noel Murray, Charles W. Clark, Christopher J. Lobb, William D. Phillips, Edwards Mark, Gretchen K. Campbell
Atomtronics is an emerging interdisciplinary field that seeks new functionality by creating devices and circuits where ultra-cold atoms play a role analogous to the electrons in electronics. Hysteresis in atomtronic circuits may prove to be a crucial