Applied Dynamics Seminar   (

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 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

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


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

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


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

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



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

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

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,
Title: Direct Observation of Azimuthal Correlations between
DNA in Hydrated Aggregates

June 2
Speaker: Dietmar Plentz, NIH, NIMH
Title: Neuronal avalanches in the brain