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Search Publications by: James(Trey) Porto (Fed)

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Displaying 26 - 50 of 91

Pneumatically Actuated and Kinematically Positioned Optics Mounts

September 4, 2013
Author(s)
Roger C. Brown, Steven Olmschenk, Wu Saijun, Ari Dyckovsky, Robert Wyllie, James V. Porto
We present two complementary designs of pneumatically actuated and kinematically positioned optics mounts: one designed for vertical mounting and translation, the other designed for horizontal mounting and translation. The design and measured stability

Light polarization and quantum interference effects in unresolvable atomic lines: application to a precise measurement of the 6,7Li D2 lines.

March 7, 2013
Author(s)
Roger C. Brown, Saijun Wu, James V. Porto, Craig J. Sansonetti, Clayton Simien, Samuel M. Brewer, Joseph N. Tan, John D. Gillaspy
We characterize the effect of quantum interference of light scattering on the line shapes and measured line positions in atomic spectra. These effects occur when the excited state splittings are of order the excited state line widths, and represent an

Loop Structure Stability of a Double-Well-Lattice BEC

December 26, 2012
Author(s)
James V. Porto, Hoi-Yin Hui, Ryan Barnett, Sankar Das Sarma
In this work, we consider excited many-body mean-field states of bosons in a double-well optical lattice by investigating stationary Bloch solutions to the non-linear equations of motion. We show that, for any positive interaction strength, a loop

Dynamically Slowed Collapse of a Bose-Einstein Condensate with Negative Scattering Length

December 3, 2012
Author(s)
Karina K. Jimenez Garcia, Robert L. Compton, Yu-Ju Lin, James V. Porto, Ian B. Spielman
We rapidly change the scattering length a_s of a ^{87}Rb Bose-Einstein condensate by means of a Feshbach resonance, simultaneously releasing the condensate from its harmonic trapping potential. When a_s is changed from positive to negative, the subsequent

Absolute transition frequencies and quantum interference in a frequency comb based measurement of the 6,7Li D lines

July 6, 2011
Author(s)
Craig J. Sansonetti, Clayton Simien, John D. Gillaspy, Joseph N. Tan, Samuel M. Brewer, Roger C. Brown, Saijun Wu, James V. Porto
Optical frequencies of the D lines of 6,7Li were measured with a relative accuracy of 5x10-11 using an optical comb synthesizer. Quantum interference in the laser induced fluorescence for the partially-resolved D2 lines was found to produce polarization

Differential Light Shift Cancellation in a B-Field Insensitive Transition of 87Rb

February 11, 2011
Author(s)
Radu S. Chicireanu, Karl D. Nelson, Steven M. Olmschenk, Nathan Lundblad, A. Derevianko, James V. Porto
We demonstrate substantial cancellation of the differential light shift of a magnetic-field-insensitive microwave hyperfine (clock) transition in 87Rb atoms trapped in an optical lattice. Up to 95.5% of the differential light shift is cancelled while

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

Randomized Benchmarking of Atomic Qubits in an Optical Lattice

November 4, 2010
Author(s)
Steven M. Olmschenk, Radu S. Chicireanu, Karl D. Nelson, James V. Porto
We perform randomized benchmarking on neutral atomic quantum bits (qubits) confined in an optical lattice. Single qubit gates are implemented using microwaves, resulting in a measured error per randomized computational gate of 1.4(1) x 10−4 that is

Phases of a 2D Bose Gas in an Optical Lattice

September 9, 2010
Author(s)
Karina K. Jimenez Garcia, Yu-Ju Lin, James V. Porto, Ian B. Spielman
Ultra-cold atoms in optical lattices realize essential models in condensed matter physics. Like with most experiments with ultra-cold atoms, our Rubidium-87 Bose Einstein condensate is confined in a harmonic trapping potential that persists even when

Adiabatic Preparation of Many-Body States in Optical Lattices

June 22, 2010
Author(s)
James V. Porto, Anders Sorensen, Ehud Altman, Michael Gullans, Mikhail Lukin, Eugene Demler
We analyze a technique for the preparation of low entropy many-body states of atoms in optical lattices based on adiabatic passage. In particular, we show that this method allows preparation of strongly correlated states as stable highest energy states of

Synthetic Magnetic Fields for Ultracold Neutral Atoms

December 3, 2009
Author(s)
Yu-Ju Lin, Robert L. Compton, Karina K. Jimenez Garcia, James V. Porto, Ian B. Spielman
Neutral atomic Bose condensates and degenerate Fermi gases have realized important many-body phenomena in their most simple and essential forms, without many of the complexities usually associated with material systems. A rich source of physics in

Effective three-body interactions of neutral atoms in optical lattices

September 15, 2009
Author(s)
Philip Johnson, Eite Tiesinga, James V. Porto, Carl J. Williams
We show that virtual excitations of neutral bosons to higher vibrational states in a three dimensional optical lattice generate effective, tunable, attractive three-body interactions. These effective processes can quickly decohere coherent states held in

Rapid Production of ^87^Rb BECs in a Combined Magnetic and Optical Potential

August 31, 2009
Author(s)
Yu-Ju Lin, Abigail R. Perry, Robert L. Compton, Ian B. Spielman, James V. Porto
We describe an apparatus for quickly and simply producing ^87^Rb Bose-Einstein condensates. It is based on a magnetic quadrupole trap and a red detuned optical dipole trap. We collect atoms in a magneto-optical trap (MOT) and then capture the atom in a

Optical Lattice-Based Addressing and Control of Long-Lived Neutral-Atom Qubits

July 6, 2009
Author(s)
Nathan Lundblad, J Obrecht, Ian B. Spielman, James V. Porto
The establishment of a scalable, addressable, and long-lived scheme for quantum computing would be a scientific watershed, harnessing the laws of quantum physics to solve classically intractable problems. Many proposed computational platforms are driven by

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

Improving Correlations with Inelastic Loss

June 6, 2008
Author(s)
James V. Porto
Correlations are one of the central features of modern condensed matter physics. They arise in systems where the behavior of any given particle in a system depends strongly on all the other particles. Such correlations are what help distinguish the

Atoms in a Radio-Frequency-Dressed Optical Lattice

April 18, 2008
Author(s)
Ian B. Spielman, James V. Porto, William D. Phillips, Ben Brown, Patricia Lee, Nathan Lundblad
We load cold atoms into an optical lattice dramatically reshaped by radio-frequency coupling of statedependent lattice potentials. This radio-frequency dressing changes the unit cell of the lattice at a subwavelength scale, such that its curvature and

Controlled Exchange Interaction Between Pairs of Neutral Atoms in an Optical Lattice

July 26, 2007
Author(s)
M Anderlini, Patricia J. Lee, Ben L. Brown, Jennifer Sebby-Strabley, William D. Phillips, James V. Porto
Ultra-cold atoms trapped by light, with their inherent quantum coherence and controllability, provide an attractive system for quantum information and for the simulation of complex problems in condensed matter physics. Quantum information processing

Subwavelength Addressibility and Spin-Dependent Transport in a Double-Well Optical Lattice

July 11, 2007
Author(s)
Patricia J. Lee, M Anderlini, Ben L. Brown, Jennifer Sebby-Strabley, William D. Phillips, James V. Porto
We report the experimental demonstration of site-selective RF addressing of atoms with sub-wavelength resolution in a spin-dependent optical lattice of double wells. We also show spin-dependent transport: coherent spatial separation of atomic wave packets

Preparing and Probing Atomic Number States With an Atom Interferometer

May 17, 2007
Author(s)
Jennifer Sebby-Strabley, Ben L. Brown, M Anderlini, Patricia J. Lee, William D. Phillips, James V. Porto, Philip R. Johnson
We describe the controlled loading and measurement of number-squeezed states and Poisson states in individual sites of a double well optical lattice. These states are input to an atom interferometer that is realized by symmetrically splitting individual

The Mott Insulator Transition in a Two Dimensional Atomic Bose Gas

February 22, 2007
Author(s)
Ian B. Spielman, William D. Phillips, James V. Porto
Cold atoms confined in periodic potentials are remarkably versatile quantum systems for implementing simple models prevalent in condensed matter theory. Here we realize the 2D Bose-Hubbard model by loading a Bose-Einstein condensate into an optical lattice