The seminar is sponsored jointly by the Institute for Physical Science
and Technology (IPST), the Math Dept, and the Institute for Research in
Electronics and Applied Physics (IREAP) and is organized by Wolfgang Losert with
help from Brian
Hunt. The format of the seminar includes lunch (we provide pizza
and sodas on a first-come-first-served
basis for $4 per person, or you may bring your own lunch) and two
20-minute
talks that emphasize applicable dynamics.
You can join our mailing
list, to receive seminar announcements via email. This mailing
list is
administered via self-subscription: Simply send emailfrom the
email
address you wish to subscribe to
majordomo@glue.umd.edu
and type "subscribe
appldynsem" in the body of the email message (not the subject
line).
To remove your email address from the list, type "unsubscribe
appldynsem", in the message body.
All seminars are Thursday at 12:15 pm
in
Room 1207,
Energy Research
Building (unless otherwise noted)
Fall 2006
Sept 21
-------
Speaker: Stefan Koehler, Emory University
Title: Swimming in a granular medium
Sept 28
-------
Speaker1: TBA
Oct 5
-----
Speaker 1: Shmuel Fishman, Technion
Title: Tunneling Out of Phase Space Islands of Maps.
Speaker 2: Matt Cornick, University of Maryland
Title: State Estimation of a Rayleigh-Benard Convection Experiment
Abstract (Shmuel Fishman, TALK1)
Experimentally observable Quantum Accelerator Modes are used as a test
case for the study of some general aspects of quantum decay from
classical stable islands immersed in a chaotic sea. Different regimes of
tunneling, marked by different quantitative dependence of the lifetimes
on the effective Planck's constant, are identified, depending on the
resolution of KAM substructures that is achieved on its scale. The
theory of Resonance Assisted Tunneling is revisited, and found to well
describe decay whenever applicable. Relevance for various physical
systems will be discussed.
Abstract (Matthew Cornick, TALK2)
Data Assimilation (DA) refers to the estimation of a dynamical system's
state from the combined knowledge of past observations (possibly incomplete
and noisy) and knowledge of an approximate model for the systems time
evolution. Here we consider DA for spatio-temporally chaotic systems, and,
in particular, we study the Local Ensemble Kalman Filter DA technique. We
have applied this technique to Rayleigh-Benard convection undergoing spiral
defect chaos. Using a system model (Boussinesq equations) and time series of
noisy shadowgraphs we obtain estimates of the temperature and velocity field
everywhere in a convection cell. This technique provides us with an indirect
measurement of quantities previously inaccessible such as mean flow. We also
demonstrate the utility of this method for forming parameter estimates.
Oct 12
------
Speaker: Juri Toomre, JILA and Dept of Astrophysical
& Planetary Sciences, University of Colorado
Title: Unfolding the sources of solar magnetism
Oct 19
------
Speaker: Juan G Restrepo, Northeastern University
Title: TBA
Oct 26
------
Speaker: TBA
Nov 2
-----
Speaker 1: TBA
Speaker 2: Andrew Pomerance, UMD
Title: TBA
Nov 9
-----
Speaker 1: Kyle Gustafson, UMD
Title: TBA
Speaker 2: Cory Poole, UMD
Title: TBA
Nov 16
------
Speaker: Martin Van Hecke, Univ of Leiden
and: Burgers Symposium
Nov 23
------
Thanksgiving
Nov 30
------
Speaker: TBA
Dec 7
----------
Speaker: Dan Gauthier, Duke University
Title: TBA
--------------------------------------------------------------------------------
Spring 2006
--------------------
No seminar March 16 (APS March meeting) and March 23 (Spring Break)
March 30
--------
Speaker: Tsampikos Kottos, Wesleyan University
Title: Quantum Graphology
- one long talk
April 6
-------
Speaker1: Steve Schiff, GMU
Title: Spatiotemporal Organization of Cortical Dynamics
Speaker 2: Lou Pecora, NRL
Title: A Unified Approach to Attractor Reconstruction
Co-Authors: Tom Carroll NRL, Linda Moniz, US Geological Survey
April 13
--------
Speaker1: Sean Humbert, UMD
Title: Extracting Useful Information from Retinal Image Motion:
Applications for Autonomous MAV/UAV Guidance,
Navigation
and Control
Speaker 2: TBA
April 20
--------
Speaker: Evelyn Sander, George Mason University
Title: Crossing bifurcations and unstable dimension variability
Speaker2:
April 27
--------
Speaker: Gabe Spalding, Wesleyan
Title: TBA
- one talk
May 4
-----
Speaker: Vered Rom-Kedar, Weizmann Institute
Title: TBA
----------------------------------------------------------
Feb 2
-----
Speaker: Benny Davidovitch
Title: Shear banding in complex fluids: Hints from colloidal
crystals
Abstract:
When sheared out of equilibrium, a variety of complex fluids exhibit
an unusual behavior, where bands of high and low shear rates are
spontaneously formed. This phenomenon is typically attributed to a
nonlinear material rheology. In this talk I will describe a similar
phenomenon observed in oscillatory shear experiment on dense
colloidal crystal. I will explain how the experimental data reflect a
linear, rather than nonlinear material rheology. This observation
leads us to suggest an alternative theory for shear banding, as a
coexistence under nonequilibrium conditions between two linearly
responding phases of a complex fluid. Some possible consequences will
be discussed, such as the singular role played by near-wall pure
solvent layers, and nonequilibrium generalizations of
Clausius-Clapeyron's coexistence formula.
-one long talk
Feb 9
-----
Speaker: Mason Porter, California Institute of Technology
Title: Bose-Einstein Condensates in Optical Lattices and
Superlattices
Bose-Einstein condensates (BECs), formed at extremely low
temperatures when particles in a dilute gas of bosons condense into the
ground state, have generated considerable excitement in the atomic
physics community, as they provide a novel, experimentally-controllable
regime of fundamental physics. In this talk, I will discuss my
research
on the macroscopic dynamics of coherent structures in BECs loaded into
optical lattice and superlattice potentials, for which I employ methods
from dynamical systems and perturbation theory. Using Hamiltonian
perturbation theory, I will give an analytical construction of
wavefunctions (observed in recently reported experiments) whose spatial
periodicity is an integer multiple of the lattice period. I will also
discuss BECs in superlattice potentials and how to manipulate solitary
waves controllably with appropriate temporal adjustments of such
potentials. Time permitting, I will briefly discuss more recent
work on
parametric excitation of BECs and work in progress on BECs with
inhomogeneous (space-dependent) scattering lengths.
- one long talk
Feb 23
------
Speaker: Richard E Prange, Univ of Maryland
Title: How to get rich in the stockmarket
Mar 2
-----
Speaker: Michelle Girvan, Santa Fe Institute
Title: The Structure and Dynamics of Complex Networks
Abstract:
Many systems take the form of networks: examples include the
Internet, the World-Wide Web, distribution networks, neural networks,
biochemical networks, food webs, and social networks. Drawing on
techniques from statistical physics and dynamical systems,
researchers have begun to take a complex systems approach to
understanding these networks, as they cannot be well-described by
completely structured or completely random representations. In
this
talk, I will discuss the interplay between connectivity and dynamics
in networked systems. In the first part of the talk, I will
present
a set of novel algorithms for finding modularity in complex networks
and discuss applications for their use. In the second part of the
talk, I will introduce a simple model to show how network topology
can effect synchronization dynamics and the distribution of basin
sizes. Finally, I will give an outlook for the future of complex
networks and offer some suggestions for research directions to help
our understanding catch up to our enthusiasm about the dynamics--
connectivity relationship.
Mar 9
-----
Speaker: Ellak Somfai, Oxford University
Title: Frictional Granular Packings: Force Networks and Jamming
Abstract:
---------
Concepts from statistical mechanics are readily applied to
granular matter, which consists of packings made of macroscopic
particles. I will discuss two aspects:
1) The spatial structure of the disordered granular force networks
has been elusive for some time. Using tools of equilibrium phase
transition, we report evidence that clusters of particles that
interact via relatively strong forces are scale invariant.
Analysing granular packings generated by molecular dynamics
simulations reveal that despite the apparent visual variation,
force networks of different parameters (pressure, friction, etc.)
have identical scaling exponents and scaling function, and thus
determine a universality class. Remarkably, the flat ensemble of
force configurations belongs to the same universality class, while
some widely studied simplified models do not.
2) It has been proposed recently that the point in parameter
space, where a frictionless granular packing starts to support
a finite load, is characterized by a "jamming transition" reminiscent
of thermodynamic phase transitions. I will discuss how this
applies
to frictional packings, including scaling of elastic moduli and sound
velocities. We probe the characteristic time scales of
two-dimensional frictional granular media close to the jamming
transition by studying their vibrational properties. Both for
large
and for zero friction, the characteristic frequency vanishes when
the pressure is lowered towards zero, but for moderate friction
it saturates at a finite value. This is identical to the behaviour
of the excess number of contacts per particle, relative to the
minimally allowed isostatic value.
--------------------------------------------------------------------------------
Fall 2005
--------------------
December 1
------------
Speaker: Will Ray, University of Maryland
Title: Crisis in a semiconductor laser with optical
feedback
- one short talk
Dec 8
-------
Speaker 1: Erin Rericha, University or Maryland
Title: TBA
Speaker 2: Amy Finkbiner, University of Maryland
Title: A dynamical approach to a
self-adapting
peer-to-peer system
Dec 15
------
No seminar
----------------
-------------------------------
SPRING 06
---------
Feb 2
-----
Feb 9
-----
Speaker: Steve Schiff, GMU
Title: TBA
Feb 16
------
Feb 23
------
March 30
--------
Speaker: Tsampikos Kottos, Wesleyan University
Title: Quantum Graphology
- one long talk
To be scheduled
------
======================================================
PAST SEMINARS
-------------
Sept 8
------
Speaker 1: James Hart, University of Maryland
Title: Simulations of Time Domain
Scattering from Chaotic
Microwave Cavities
Sept 15
-------
Speaker 1: Woodrow Shew, Ecole Normal Superieur, Lyon
Title: Rising bubbles and wake induced
path
instabilities
Speaker 2: Mike Dennin, UC Irvine
Title: Flowing foam: a possible
phase transition
Sept 22
-------
Speaker 1: Sejin Han, UMD and NIH
Title: Collagen Network formation
Sept 29
-------
Speaker 1: Jennfier Galanis, NICHD/NIH
Title: Spontaneous Patterning of Confined
Granular Media
Speaker 2: Jeff Urbach, Georgetown University
Title: Shaking and shearing in a
vibrated granular layer
Oct 6
-----
Speaker 1: Michael Newey, UMD
Title: Segregation Transients in a
granular tumbler flow
Oct 13
------
Speaker 1: Harmut Erzgreaeber, Dept. of Physics, Vrije Univ.
Amsterdam
Title: Bifurcation analysis of a
semiconductor laser with
filtered optical feedback
Speaker 2: Greg Bewley & Dan Lathrop, University of Maryland
Title: Superfluid Vortices
Oct 20
------
Speaker 1 : Shmuel Fishman
Title: Quantum Resonances for
Kicked Cold Atoms
Speaker 2: Kris Helmerson, Physics Laboratory, NIST,
Gaithersburg, MD
Title: Quantum transport of a
periodically kicked
Bose-Einstein condensate
Oct 27
------
Speaker 1: Samuel Zambrano, URJC, Spain
Title: Chaotic Resonance: a "stochastic resonance"
phenomenon induced by
a chaotic signal
Speaker 2: Dr Ban Jung Chao, Taiwan
Title: Entropy on 2 dimensional lattices
Nov 3
-----
Speaker: Hernan Makse, Levitch Institute, CCNY
Title: Self-similarity of complex networks
- one long talk
Nov 10
------
Speaker 1: Kaveri Joshi, University of Maryland
Title: Turbulent Thermal Convection in Liquid
Sodium
Speaker 2: Santiago Tirana, University of Maryland
Title: Laboratory experiments on liquid metal
spherical-Couette flows
Nov 17
------
Speaker: Lai Sang Young, New York University
Title: Nonequilibrium Steady States for Some Hamiltonian
and Stochastic
Models
======================================================
2004/Spring 2005 SEMINARS
-------------
Feb 10
------
Speaker1: Istvan Szunyogh, Univ of Maryland
Title: On the origin of locally low dimensional chaos in
atmospheric dynamics
Speaker2 :John Harlim, Univ of Maryland
Title: An Efficient Local Ensemble Kalman Filter
Feb 17
------
Speaker: Bruce Miller, TCU
Title: Dynamics of Gravitational Systems
Mar 3
-----
-------
Speaker:Peter Lenz, Univ Marburg
Title: Membranes with Rotating Motors
Host: Bruno Eckhard
- one long talk
Mar 10
------
Speaker: Aleksandr Y. Ukhorskiy, Johns Hopkins Univ.
Title: Complexity in Magnetospheric Dynamics: From Modeling
to Forecasting
Speaker: Masahiro Toiya, UMD
Title: Rod Penetration through a Granular Pile
Mar 17
------
Speaker: Leah Chock, NRL
Title: Bifurcations and chaotic desynchronization in a
multistrain disease model with seasonal forcing
Mar 31
------
Speaker 1: Irene Moroz, Oxford Univ, UK
Title: The extended Malkus-Robbins dynamo as a perturbed
Lorenz system
Speaker 2: Jennifer Curtis, Univ Heidelberg
Title: Mechanics of hyaluronan-mediated cell adhesion
April 1
-------
Joint Applied Dynamics - AMO seminar
Speaker: Jesper Glueckstaed, Riso
Title: Optical multi-particle manipulation based on GPC
(generalized Phase Contrast)
Host: Losert
-one long talk -
Apr 7
-----
Speaker 1: Ramakrishna Ramaswamy, Centre for Systems Biology,
Institute for Advanced Study, Princeton
Title: Aperiodic and nonchaotic attractors
- one long talk
Apr 14
------
Speaker 1: Joe Skufka, UMD
Title: Boundary to turbulence in plane Couette flow
Speaker 2: Ben Shapiro, UMD
Title: Steering Particles by Micro Flow Control
Apr 21
------
Speaker: Konstantin Mischaikow, Georgia Tech
Title: A topological analysis of time dependent patterns
- one long talk -
April 28
--------
Speaker 1: Philip G. McQueen, Mathematical & Statistical
Computing Laboratory, Division of Computational Bioscience, NIH
Title: Parasite vs Parasite vs Host: Counter- Intuitive Outcomes
Due to Competition for Red Blood Cells in Malaria Infections
Speaker 2: Mahesh Bandi, Univ of Pittsburgh
Title: Spatio-temporal fluctuations in the energy cascade of
a turbulent fluid
May 5
-----
Speaker 1: Romulus Breban, Department of Biomathematics, UCLA
Title: Aggregating ODE models with growing networks: a new class
of epidemic models
Speaker 2: Juan Restrepo, UMD
Title: Desynchronization waves and localized instabilities
in oscillator arrays
May 12
------
Speaker: Doug Durian, University of Pennsylvania
Title: Partition of energy for gas-fluidized grains
May 19
------
Speaker 1: Sergey Leikin, Chief, Section on Physical Biochemistry,
NICHD, NIH
Title: Direct Observation of Azimuthal Correlations between
DNA in Hydrated Aggregates
June 2
------
Speaker: Dietmar Plentz, NIH, NIMH
Title: Neuronal avalanches in the brain