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Search Publications by: William D. Phillips (Fed)

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Displaying 1 - 25 of 166

Advanced Laser Cooling for the Atomic Space Clock

October 12, 2021
Author(s)
V Boyer, L Lising, S L. Rolston, William D. Phillips
An atomic clock works by comparing the frequency of a local oscillator (a micrwave generator) with the hyperfine transition of the cesium atom at 9.2 GHz. In general, the precision of a clock is limited by the observation time. For an atomic clock, it is

Creation of Macroscopic Superposition States from Arrays of Bose-Einstein Condensates

October 12, 2021
Author(s)
J A. Dunningham, Karen G. Burnett, R Roth, William D. Phillips
We consider how macroscopic quantum superpositions may be created from arrays of Bose-Einstein condensates. We study a system of three condensates in Fock states, all with the same number of atoms and show that this has the form of a highly entangled

Bose Condensation of Photons Thermalized via Laser Cooling of Atoms

August 31, 2018
Author(s)
Chiao Wang, Michael Gullans, James V. Porto, William D. Phillips, Jacob Taylor
A Bose-Einstein condensate (BEC) is a quantum phase of matter achieved at low temperatures.Photons, one of the most prominent species of bosons, do not typically condense due to the lackof a particle number-conservation. We recently described a photon

Photon thermalization via laser cooling of atoms

July 19, 2018
Author(s)
Chiao-Hsuan Wang, Michael Gullans, James V. Porto, William D. Phillips, Jacob Taylor
The cooling of atomic motion by scattered light enables a wide variety of technological and scientific explorations. Here we focus on laser cooling from the perspective of the light — specifi- cally, the scattering of light between different optical modes

An introduction to the new SI

December 20, 2016
Author(s)
Peter J. Mohr, Sandra Knotts, William D. Phillips
Plans are underway to redefine the International System of Units (SI) around 2018. The new SI specifies the values of certain physical constants to define units. This article explains the new SI in a way that could be used to present it to high-school

Quantum and Classical Dynamics of BEC in a Large-Period Optical Lattice

April 4, 2016
Author(s)
Ian B. Spielman, Johnny H. Huckans, Bruno Laburthe-Tolra, James V. Porto, William D. Phillips
We experimentally investigate diffraction of a ^u87 Rb Bose-Einstein Condensate from a 1D optical lattice. We use a range of lattice periods and timescales, including those beyond the Raman-Nath limit. We compare the results to quantum mechanical and

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

Gauge matters: Observing the vortex-nucleation transition in a Bose condensate

June 18, 2015
Author(s)
Ian B. Spielman, LeBlanc Lindsey, Karina Jimenez-Garcia, Ross Williams, Matthew Beeler, William D. Phillips
The order parameter of a quantum-coherent many-body system includes one or more phase degrees of freedom, which, owing to the phase information's relationship to velocity, can be accessed using time-of-flight (TOF) imaging. Here, trapped Bose-Einstein

Dimensionless units in the SI

June 1, 2015
Author(s)
Peter J. Mohr, William D. Phillips
The International System of Units (SI) is supposed to be coherent. That is, when a combination of units is replaced by an equivalent unit, there is no additional numerical factor. Here we consider dimensionless units as defined in the SI, e.g. angular

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

Driving Phase Slips in a Superfluid Atom Circuit with a Rotating Weak Link

January 10, 2013
Author(s)
Kevin C. Wright, William D. Phillips, Gretchen K. Campbell
We have induced well-defined phase slips between quantized persistent current states around a toroidal atomic 23Na Bose-Einstein condensate by rotating a weak link (a localized region of reduced superfluid density) around the ring at low angular frequency

Controlling Atomic Interactions with Light

December 1, 2012
Author(s)
Ross A. Williams, Lindsay J. LeBlanc, Karina K. Jimenez Garcia, Matthew C. Beeler, Abigail R. Perry, William D. Phillips, Ian B. Spielman
For the majority of the 20th century atomic physicists used light to probe and understand atoms. Today, scientists use light to manipulate particles with unprecedented levels of control, routinely cooling atoms to a few billionths of a degree above

Partial-Transfer Absorption Imaging: A versatile technique for optimal imaging of ultracold gases

August 13, 2012
Author(s)
Gretchen K. Campbell, Sergio R. Muniz, Kevin Wright, Russell P. Anderson, William D. Phillips, Kristian Helmerson
Partial-transfer absorption imaging is a tool that enables optimal imaging of atomic clouds for a wide range of optical depths. In contrast to standard absorption imaging, the technique can be minimally-destructive and can be used to obtain multiple

Observation of a superfluid Hall effect

July 3, 2012
Author(s)
Lindsay J. LeBlanc, Karina K. Jimenez Garcia, Ross A. Williams, Matthew C. Beeler, Abigail R. Perry, William D. Phillips, Ian B. Spielman
Measurement techniques based upon the Hall effect are essential tools in condensed matter physics. Here, we report the first observation of a Hall effect in an ultracold gas of neutral atoms, revealed by measuring Bose-Einstein condensate's transport

Beyond s-wave scattering for ultracold atoms

January 20, 2012
Author(s)
Ross A. Williams, Lindsay J. LeBlanc, Karina K. Jimenez Garcia, Matthew C. Beeler, Abigail R. Perry, William D. Phillips, Ian B. Spielman
Interactions between particles can be strongly altered by their environment. Here we demonstrate a technique for modifying interactions between ultracold atoms by dressing the bare atomic states with light, creating a screened interaction of vastly

Ultracold Atoms and Precise Time Standards

September 19, 2011
Author(s)
Gretchen K. Campbell, William D. Phillips
Experimental techniques of laser cooling and trapping, along with other cooling techniques have produced gaseous samples of atoms so cold that they are, for many practical purposes, in the quantum ground state of their center-of-mass motion. Such low

Superflow in a Toroidal Bose-Einstein Condensate: An Atom Circuit with a Tunable Weak Link

March 28, 2011
Author(s)
Kevin C. Wright, Anand Ramanathan, Sergio R. Muniz, Wendell Hill, Kristian Helmerson, William D. Phillips, Gretchen K. Campbell, Christopher Lobb
We have created a long-lived (40 s) persistent current in a toroidal Bose-Einstein condensate held in an all-optical trap. A repulsive optical barrier creates a tunable weak link in the condensate circuit, which can affect the current around the loop

Synthetic Electric and Magnetic Fields for Ultracold Neutral Atoms

January 1, 2011
Author(s)
William D. Phillips, Yu-Ju Lin, Robert L. Compton, Karina K. Jimenez Garcia, Abigail R. Perry, James V. Porto, Ian B. Spielman
We use Raman coupling between magnetic sublevels of a 87Rb Bose-Einstein condensate (BEC) to create an effective vector gauge field for the neutral atoms. They behave as if they were charged particles in a magnetic vector potential. With appropriate

Observation of a 2D Bose-gas: from thermal to fractured quasi-condensate to superfluid

May 1, 2009
Author(s)
Pierre Clade, Changhyun Ryu, Anand Ramanathan, Kristian Helmerson, William D. Phillips
This paper presents experimental results on a Bose gas in a quasi-2D geometry near the Berezinskii,Kosterlitz and Thouless (BKT) transition temperature. By measuring the density profile, in situ and after time of flight, and the coherence length of the gas

A Bose-Einstein Condensate in a Uniform Light-Induced Vector Potential

March 30, 2009
Author(s)
Yu-Ju Lin, Robert L. Compton, Abigail R. Perry, William D. Phillips, James V. Porto, Ian B. Spielman
We use a two-photon dressing field to create an effective vector gauge potential for Bose-condensed ^87Rb atoms in the F=1 hyperfine ground state. The dressed states in this Raman field are spin and momentum superpositions, and we adiabatically load the

Laboratory Experiments for Fundamental Physics in Space

October 16, 2008
Author(s)
William D. Phillips
Laboratory Experiments refers generally to active spaceborne experiments as opposed to the equally important passive observation in space of signals coming from more distant sources. My purpose in this presentation is to highlight a number of opportunities

Observation of Persistent Flow of a Bose-Einstein Condensate in a Toroidal Trap

October 16, 2008
Author(s)
Changhyun Ryu, Mikkel Andersen, Pierre Clade, Vasant Natarajan, Kristian Helmerson, William D. Phillips
We have observed the persistent flow of Bose-condensed atoms in a toroidal trap. The flow persists without decay for up to 10 s, limited only by experimental factors such as drift and trap lifetime. The quantized rotation was initiated by transferring one

Quantized Rotation of Atoms From Photons With Orbital Angular Momentum

October 16, 2008
Author(s)
Mikkel Andersen, Changhyun Ryu, Pierre Clade, Vasant Natarajan, A Vaziri, Kristian Helmerson, William D. Phillips
Light can carry two kinds of angular momentum: Spin angular momentum (SAM) associated with its polarization and orbital angular momentum (OAM) associated with its spatial mode [1, 2]. The coupling of optical SAM to atoms has been known for over a century