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Search Publications by: Gretchen K Campbell (Fed)

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Displaying 1 - 20 of 20

Accurate Determination of Hubble Attenuation and Amplification in Expanding and Contracting Cold-Atom Universes

February 28, 2022
Swarnav Banik, Monica Gutierrez Galan, Hector Sosa Martinez, 1, Madison Anderson, Stephen Eckel, Ian Spielman, Gretchen K. Campbell
In the expanding universe, relativistic scalar fields are thought to be attenuated by "Hubble friction," which results from the dilation of the underlying spacetime metric. By contrast, in a contracting universe this pseudofriction would lead to

Programmable System on Chip for controlling an atomic physics experiment

July 23, 2021
Ananya Sitaram, Gretchen K. Campbell, Alessandro Restelli
Most atomic physics experiments are controlled by a digital pattern generator used to synchronize all equipment by providing triggers and clocks. Recently, the availability of well-documented open-source development tools has lifted the barriers to using

Isotope shift spectroscopy of the 1S0 to 3P1 and 1S0 to 3P0 transitions in strontium

November 19, 2020
Gretchen K. Campbell, Hirokazu Miyake, Neal Pisenti, Peter Elgee, Ananya Sitaram
Isotope shift spectroscopy with narrow optical transitions provides a benchmark for atomic struc- ture calculations, and has also been proposed as a way to constrain theories predicting physics beyond the Standard model. Here, we have measured frequency

Confinement of an alkaline-earth element in a grating magneto-optical trap

October 15, 2020
Ananya Sitaram, Peter Elgee, Gretchen K. Campbell, Daniel Barker, Nikolai Klimov, Stephen Eckel
We demonstrate a compact magneto-optical trap (MOT) of alkaline-earth atoms using a nanofabricated diffraction grating chip. A single input laser beam, resonant with the broad 1S0 to 1P1 transition of strontium, forms the MOT in combination with three

A wide-bandwidth, high-power radio-frequency driver for acousto-optic and electro-optic devices

August 6, 2019
Daniel S. Barker, Neal C. Pisenti, Alessandro Restelli, Julia K. Scherschligt, James A. Fedchak, Gretchen K. Campbell, Stephen P. Eckel
We present a design for a general-purpose radio-frequency amplifier circuit that is suitable for driving acousto-optic and electro-optic devices. Our design uses telecom amplifiers to achieve power output > 1 W over a 10 MHz to 1.1 GHz frequency range, and

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

April 19, 2018
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

An ultra-low noise, high-voltage piezo driver

December 8, 2016
Neal C. Pisenti, Alessandro Restelli, Ben J. Reschovsky, Daniel Barker, Gretchen K. Campbell
We present an ultra-low noise, high-voltage driver suited for use with piezoelectric actuators and other low- current applications. The architecture uses a flyback switching regulator to generate up to 250V in our current design, with an output of 1 kV or

Contact resistance and phase slips in mesoscopic superfluid atom transport

June 15, 2016
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
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

Enhanced Magnetic Trap Loading for Atomic Strontium

October 26, 2015
Gretchen K. Campbell, Daniel Barker, Benjamin Reschovsky, Neal Pisenti
We report on a technique to improve the continuous loading of atomic strontium into a magnetic trap from a Magneto-Optical Trap (MOT). This is achieved by adding a depumping laser tuned to the 3 P1 → 3 S 1 (688-nm) transition. The depumping laser increases

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

September 22, 2014
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
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
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
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

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

August 13, 2012
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

Superfluidity Goes 2D

August 13, 2012
Gretchen K. Campbell
In two-dimensional systems, superfluidity occurs in the absence of the long-range order associated with Bose-Einstein condensates. This phenomenon is illustrated in the direct observation of superfluidity in a two-dimensional atomic Bose gas.

Ultracold Atoms and Precise Time Standards

September 19, 2011
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
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