AMO Seminars

Determining the atomic excited-state fraction in a magneto-optical trap

Speaker: 
Yue Shen
Event Date and Time: 
Mon, 2018-10-15 12:30 - 13:30
Location: 
Henn 309
Local Contact: 
Kirk Madison
Intended Audience: 
Graduate

This talk introduces an empirical method for determining the excited-state fraction of atoms in a magneto-optical trap (MOT).

Many-body quantum chaos of ultracold atoms in a quantum ratchet

Speaker: 
Lincoln D. Carr, Colorado School of Mines, Golden, Colorado, USA
Event Date and Time: 
Wed, 2018-10-03 15:00 - 16:00
Location: 
Henn 318
Local Contact: 
Valery Milner
Intended Audience: 
Graduate

There are now over 300 quantum simulators on at least 10 separate architectures with long coherence times and controlled dynamics.  These experimental systems have generated tremendous excitement about driven interacting quantum systems resulting in physics ranging from time crystals to dynamical many-body localization.  The quantum ratchet adds a new feature to periodic driving: a preferred direction in both time and space, i.e., parity and time-reversal symmetry-breaking.   By studying weakly interacting ultracold bosons in a quantum ratchet on a ring in position, momentum, and Floquet re

Some thoughts on energy relaxation in an ultracold neutral plasma -- expanding and trapped dual-species plasmas

Speaker: 
Scott Bergeson, Brigham Young University
Event Date and Time: 
Thu, 2017-07-27 16:30 - 17:30
Location: 
Chem D-213
Local Contact: 
Ed Grant
Intended Audience: 
Graduate

The statistical mechanics of strongly coupled plasmas are not well understood. Descriptions of diffusion, viscosity, and relaxation are more complicated compared to what happens in neutral atomic gases because the Coulomb interaction is long-range. Instead of being reduced to sequential local events, momentum transfer in plasmas is typically comprised of millions of more or less simultaneous long-range "collisions." Standard kinetic theories try to capture this physics using a single term called the Coulomb logarithm, which modifies essentially every thermodynamic process.

Algebraic Approach to Phase Problem

Speaker: 
Pavel Trochtchanovitch
Event Date and Time: 
Thu, 2017-02-02 15:00 - 16:00
Location: 
Henn 309
Local Contact: 
Kirk Madison
Intended Audience: 
Graduate

In this talk we’ll discuss a “phase problem” – reconstruction of a signal from absolute value of its Fourier transform; with the only constraint being finite (though not known exactly) signal support.

With the help of “sampling theorem” it will be shown how this “phase problem” is equivalent to a system of non-linear equations; a fundamental difference between numerical solutions for 1D and 2D cases will be illustrated (why 1D case result in 2 to the power of ”number of points” solutions, and 2D case doesn’t?), and several numerical examples will be presented.

 

Measuring Everything You've Always Wanted to Know About a Light Pulse

Speaker: 
Rick Trebino, Georgia Institute of Technology
Event Date and Time: 
Thu, 2017-03-23 12:30 - 13:30
Location: 
Henn 304
Local Contact: 
Valery Milner
Intended Audience: 
Graduate

The vast majority of the greatest scientific discoveries of all time have resulted directly from more powerful techniques for measuring light.  Indeed, our most important source of information about our universe is light, and our ability to extract information from it is limited only by our ability to measure it.

Discovering and Harnessing Molecular Scale Driving Forces at the Nano/Bio Interface

Speaker: 
Jim Pfaendtner, Department of Chemical Engineering, University of Washington
Event Date and Time: 
Thu, 2017-01-26 15:30 - 16:30
Location: 
Chem D-215
Local Contact: 
Keng Chou
Intended Audience: 
Graduate

Rational design of unique solvents and surfaces holds great potential for providing new ways to use biomolecules in engineering applications, which range from biocatalysis in ionic liquids (ILs) to surface-driven self-assembly of nano/bio materials that mimic nature. Computational models such as molecular dynamics (MD) can connect the atomic scale to the mesoscale for a wide range of problems but many challenges still limit wide-ranging use of these tools to their full potential.

From Ultralong-range Molecules to Rydberg Polarons in a Bose Gas

Speaker: 
Thomas C. Killian, Rice University
Event Date and Time: 
Wed, 2016-10-05 14:30 - 15:30
Location: 
Chem D-213
Local Contact: 
Ed Grant
Intended Audience: 
Graduate

 

Rydberg atoms excited in a dense gas interact very strongly with background, ground-state atoms that lie within the Rydberg orbital. This problem has a long history, and it inspired Fermi to develop the Fermi pseudo-potential to describe the low-energy scattering of a Rydberg electron and ground-state atoms. With the availability of ultracold atomic gases, this topic has received renewed interest.

Towards High Precision Frequency Comb Spectroscopy in the Extreme Ultraviolet

Speaker: 
Gil Porat JILA/University of Colorado Boulder
Event Date and Time: 
Fri, 2016-08-26 14:00 - 15:00
Location: 
AMPEL 311
Local Contact: 
David Jones
High precision spectroscopy of few-electron atoms and ions is strongly motivated by the need to test fundamental theory (e.g. quantum electrodynamics) in simple systems, amenable to precise calculation for comparison with experimental measurement. Additionally, transitions from the ground state are most susceptible to nuclear structure effects (e.g. charge radius), making them appealing as tools for testing nuclear structure theory.

Orientation and Alignment Echoes

Speaker: 
Ilya Averbukh, Weizmann Institute of Science
Event Date and Time: 
Thu, 2016-07-14 12:30 - 13:30
Location: 
Hennings 302
Local Contact: 
Valery Milner
Intended Audience: 
Graduate

 

Echoes are common in many areas of physics, including NMR, plasma physics, nonlinear optics, cavity quantum electrodynamics, cold atoms physics, and even high energy hadron beams experiments.

Recently we discovered (probably) the simplest classical system featuring the echo phenomenon — a collection of randomly oriented free rotors with dispersed rotational velocities. Following excitation by a pair of time-delayed impulsive kicks, the mean orientation or alignment of the ensemble exhibits multiple echoes in space and time.

Magnetically manipulated atomic and molecular beams

Speaker: 
Gil Alexandrowicz, Technion - Israel Institute of Technology
Event Date and Time: 
Mon, 2016-06-20 14:00 - 15:00
Location: 
Chem D-215
Local Contact: 
Roman Krems
Intended Audience: 
Graduate

A common theme to the activities in our group is magnetically manipulating beams of atoms and molecules. In this talk I will briefly describe the different types of experiments which use magnetic manipulations.  In the first type we exploit the nuclear spin of a helium-3 atom to perform time-depended atom-interferometry experiments.

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