| Institution | ETHZ Zurich |
| Date of Colloquim | Aug. 31 |
| Colloquium Title | What does the electric field look like inside a complex
laser cavity? |
| Abstract :
The nature of the electric field in a laser well above threshold has been a
long-standing question in laser theory, complicated by the difficulty of
treating exactly both the non-linear interaction and the openness of a laser
cavity. With the advent of complex lasers, such as random, wave-chaotic and
photonic bandgap lasers, this mathematical challenge has become of great
relevance. I will discuss recent results emerging from an extension of
semi-classical laser theory to open systems with a high degree of spatial
complexity in the linear (passive cavity) regime. Certain concepts and
methods that has been originally devised for disordered/chaotic electronic
systems will be shown to be highly effective in describing spatio-temporal
phenomena in complex lasers.
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| Host |
Philippe Jacquod |
| Dates of Visit |
Aug 29 - Sep 4 |
| Travel Itinerary |
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| Hotel Information |
Stay's at host's place |
| Citizenship |
Turkish |
| Institution | University of Missouri, Columbia |
| Date of Colloquim | Sep. 14 |
| Colloquium Title | How does the spin-polarized current manipulate magnetization states of
> nano-magnets? |
| Abstract
Today's forefront technological applications of magnetic materials are based on control and manipulation of magnetization on the scale of nanoseconds and nanometers. The convention method of using a magnetic field to write magnetization states has encountered increasing difficulties. Recently, a novel scheme based on spin-polarized current-driven magnetization switching has emerged as a most promising alternative for faster and denser magnetic technology. In this talk, I will discuss why and how a spin-polarized current interacts with the magnet from the principle of spin angular momentum conservation. Then I will present our recent work in understanding current-driven domain wall motion, distortion, and spin-wave excitations in a magnetic nanowire. |
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| Host |
Mike Shupe / Philippe Jacquod |
| Dates of Visit |
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| Travel Itinerary |
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| Hotel Information |
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| Citizenship |
| Institution | University of Arizona |
| Date of Colloquim | Sep 28 |
| Colloquium Title | Peeking into a Neutron Star: Neutrons,
Condensates, or Quarks? |
|
Neutron stars are the densest objects in the universe and may contain
hyperon-dominated matter, condensed mesons, or even deconfined or
strange quark matter. Because of their low temperatures and high
chemical potentials, the physical conditions in their interiors differ
greatly from the dense conditions of the early universe or those
achieved at hadron colliders. This region of the QCD phase diagram can
only be probed through astrophysical observations that measure the
mass and radius of neutron stars. For decades, this effort has been
hampered by a number of model uncertainties as well as by the lack of
accurate measurements of different spectroscopic phenomena from a
single source that would break the degeneracies between the neutron
star parameters of interest. I discuss how we can now overcome these
problems by combining recent developments in our understanding of
neutron star atmospheres with observations of distinct phenomena from
the same neutron star source. In particular, I will present a unique
measurement of the mass and radius of the neutron star in EXO
0748-676. The high inferred mass and large radius of this neutron star
rule out all the soft equations of state of neutron star matter.
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| Host |
NA |
| Dates of Visit |
NA |
| Travel Itinerary |
NA |
| Hotel Information |
NA |
| Citizenship |
NA |
| Institution | JILA University of Colorado at Boulder |
| Date of Colloquim | October 5 !! Room OSC 307 !!
joint colloquium with Optical Sciences |
| Colloquium Title | |
| Abstract
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| Host |
Pierre Meystre (?) |
| Dates of Visit |
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| Travel Itinerary |
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| Hotel Information |
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| Citizenship |
| UA ADVANCE Distinguished Lecturer |
| Institution | Colorado School of Mines |
| Date of Colloquim | Oct. 12 |
| Colloquium Title | Cat States in Bose-Einstein Condensates |
|
It is vital not to take our most fundamental physical theories for
granted. For example, researchers have looked for deviations from the
gravitational inverse square law at very small sub-micron length scales.
Similarly, one can ask what predictions of quantum mechanics might break
down in untested regimes. Since the classical world is macroscopic and
the quantum world is microscopic, a natural place to test quantum
mechanics is in mesoscopic physics. Macroscopic superposition is a
largely untested mesoscopic prediction of quantum mechanics.
An excellent candidate for macroscopic superposition states, also called
Cat (or NOON) States after Schrodinger's famous gedanken experiment, is
a
Bose-Einstein condensate in a double well. Mathematically, this is a
fifty year old quantum many body problem. The experimental context of
Bose-Einstein condensates gives one hope to observe the first truly
large
scale Cat States of matter. We show that Bose-Einstein condensates
require
two new energy scales. We introduce the role of the dimensionality of
each well. We demonstrate that the many body wavefunction serves to
protect Cat States from decoherence. Finally, we present a practical
scheme for dynamic realization of such states.
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| Host |
Pierre Meystre |
| Dates of Visit |
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| Travel Itinerary |
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| Hotel Information |
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| Citizenship |
| Institution | Carnegie Mellon University |
| Date of Colloquim | Oct 19 |
| Colloquium Title | The Problem of Motion: It's Not Just Academic, it's Astronomy. |
|
Consider one of the most rudimentary problems in physics. Drop a mass
(m) at rest from a height (d)
above the surface of the earth, and calculate its position as a
function of time y(t). The solution y(t)=d-\frac{1}{2} g t^2, taught in
freshman physics is an excellent approximation to the solution.
Suppose, however, that we wish to be more exact. There are multiple
sources of corrections to this solution. Standard
ideas in general relativity allow one correct for relativistic effects.
However, a closer look
reveals that there exist many more complications. For instance, the
mass will not
be point-like, and will radiate gravitational waves. It will also deform
under the influence of the gravitational field. These effects are
intertwined, and their inclusion can make the problem of solving
for the trajectory intractable.
In the past, solving this problem was only of academic interest, but
now our ability to distinguish between astrophysical objects in the
next generation of gravity
wave detectors will rely upon its solution.
In this talk, I will discuss how one can use ideas developed for
statistical mechanics and quantum field theory to solve this ``problem
of motion'' in a systematic fashion.
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| Host |
Sean Fleming |
| Dates of Visit |
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| Travel Itinerary |
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| Hotel Information |
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| Citizenship |
| Institution | |
| Date of Colloquim | Oct. 26 |
| Colloquium Title | Large, room-temperature magnetoresistance in organic light-emitting diodes
|
| We report on the discovery and experimental characterization of a magnetoresistive effect
in organic light-emitting diodes with a magnitude of up to 10% at room temperature for
small magnetic fields, B = 10mT. Its discovery came as a surprise since it has often been
believed that large magnetoresistance at room-temperature requires magnetic materials. We
show that the effect is caused by the interaction between paramagnetic carriers. These
interactions obey spin-selection rules that are sensitive to the presence of nuclear
magnetic fields. We will also describe possible applications of the effect.
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| Host |
Sumit Mazumdar |
| Dates of Visit |
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| Travel Itinerary |
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| Hotel Information |
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| Citizenship |
| Institution | Johns Hopkins |
| Date of Colloquim | Nov 2 |
| Colloquium Title | Duality in Physics and in Superconductors |
| Duality is among the favorite tools of a theoretical physicist: it seems to
offer something for nothing. A strongly interacting theory, hopelessly
beyond the grasp of a perturbative expansion, can occasionally be recast as
a weakly interacting problem in terms of new degrees of freedom, themselves
hugely non-linear, non-local objects in the original language. Add a dash of
topological correctness and one is in the business of duality. From
superstrings to quantum electrodynamics to Ising magnets such duality
mappings delight theorists and frustrate experimentalists (and other
reasonable people).
In recent years, from various directions and within different physical
contexts, many theoretical descriptions of strongly correlated electron
systems have converged to the form of a gauge theory, with duality often
playing a crucial role. In this talk I will discuss how such gauge theories
might help illuminate our understanding of some important classes of
materials, notably high temperature superconductors. I will dwell on the
concepts of s-wave and d-wave duality and on the elegant symmetries
associated with resulting gauge theories -- these routinely turn out to be
"emergent", i.e. are dynamically generated from bare condensed matter
Hamiltonians of far lesser symmetry. It will be argued that the humanity's
only hope of understanding strongly correlated superconductors rests on such
dual theories. The question of experiment, a merciless scourge of condensed
matter theory, will also be addressed.
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| Host |
Philippe Jacquod |
| Dates of Visit |
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| Travel Itinerary |
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| Hotel Information |
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| Citizenship |
| Institution | Technion, Israel Institute of Technology / Yale |
| Date of Colloquim | Nov 9 |
| Colloquium Title | Photon localization and Dicke superradiance in atomic gases: crossover to a
"small world" network |
| Abstract
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|
| Host |
Philippe Jacquod |
| Dates of Visit |
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| Travel Itinerary |
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| Hotel Information |
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| Citizenship |
| Institution | Thomas
Jefferson National Accelerator Facility and College of William and
Mary |
| Date of Colloquim | Nov. 30 |
| Colloquium Title | Overview of JLAB physics program
and objective |
| Abstract
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|
| Host |
Jan Rafelski |
| Dates of Visit |
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| Travel Itinerary |
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| Hotel Information |
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| Citizenship |
| Institution | Purdue University |
| Date of Colloquim | TBA |
| Colloquium Title | Cochlear Implants |
| Abstract
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|
| Host |
Sean Fleming |
| Dates of Visit |
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| Travel Itinerary |
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| Hotel Information |
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| Citizenship |
| This talk needs to be cross
listed with the med school etc. We'll need a big room. |