Sedimentation, trapping and up-stream swimming in a model active suspension.
The Indian Institute of Mathematical Science, India
Suspensions of self-propelling particles, of both
biological and non-biological origin, are systems rich in
non-equilibrium phenomena. We simulate by lattice Boltzmann the
nonequilibrium steady states of run-and-tumble particles (inspired by
a minimal model of bacteria), interacting by far-field hydrodynamics,
subject to confinement. Under gravity, hydrodynamic interactions
barely perturb the steady state found without them, but for particles
in a harmonic trap such a state is quite changed if the run length is
larger than the confinement length: a self-assembled pump is formed.
Particles likewise confined in a narrow channel show a generic
upstream flux in Poiseuille flow: chiral swimming is not required.
Fluctuation Theorems for Many Particle Systems
Debra J. Searles(a) and Denis J. Evans(b)
(a) School of Biomolecular and Physical Sciences and Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane, Qld 4111, AUSTRALIA
(b) Research School of Chemistry, Australian National University, Canberra, ACT 0200, AUSTRALIA
Recent Insights into the Order Parameter Distribution at a Critical Point
Laboratoire de Physique des Solides, France
Fluctuation-dissipation in out of equilibrium systems
Laboratoire de Physique de l'ENS de Lyon, France
In this lecture we will discuss two aspects of the applications of recent
theoretical results for out of equilibrium systems to experiments.
Dynamics of a flexible polymer in shear flow
Physics Department, IIT Bombay, India
Motion of a single polymer in a fluid flow field is of considerable interest. In the case of shear flow, we show that many answers can be derived analytically for both the statics and dynamics of a linear (flexible) polymer. In particular, reasonable estimates can be made for a quantity related to the statistics of tumbling of the polymer. Some results for elongational and rotational flows will also be discussed.
Learning as a phenomenon occurring in a critical state
Lucilla de Arcangelis
Second University of Naples, Italy
Large deviation functions and fluctuation theorems in heat transport.
Raman Research Institute, India
The large deviation function contains information on the probability of rare fluctuations of a stochastic variable. In this talk the large deviation function for heat transport will be discussed. Results on the analytic and numerical computation of the large deviation function will be decsribed. The relevance of these results for fluctuation theorems in the context of transport will also be mentioned.
The scaling of fidelity susceptibility close to a quantum multicritical point.
IIT Kanpur, India
Fidelity and fidelity susceptibility are information theoretic
measures of a continuous quantum phase transition. Especially, the fidelity
susceptibility shows a scaling relation at (or in the vicinity of) a
quantum critical point with the exponents given by the quantum critical
exponents. We show that close to a multicritical point an altogether
different scenario emerges:
Explosive percolation: a numerical analysis
Institute for Scientific Interchange, Italy
Percolation is one of the most studied processes in statistical physics. A recent paper by Achlioptas et al. [Science 323, 1453 (2009)] has claimed that the percolation transition, which is usually continuous, becomes discontinuous ("explosive") if links are added to the system according to special cooperative rules (Achlioptas processes). In this paper we present a detailed numerical analysis of Achlioptas processes with product rule on various systems, including lattices, random networks a' la Erdoes-Renyi and scale-free networks. We find that the explosive percolation transition displays analytical behavior, like power law distributions of cluster sizes, compatibly with recent work showing that the transition is actually continuous.
Weighted planar stochastic lattice with scale-free coordination number disorder and multifractal size disorder
M. K. Hassan (a), M. Z. Hassan (b) and N. I. Pavel (a)
(a) Theoretical Physics Group, Department of Physics, University of Dhaka, Dhaka 1000, Bangladesh
(b) Institute of Computer Science, Bangladesh Atomic Energy Commission, Dhaka 1000, Bangladesh
Entropy production and fluctuation relations for KPZ growth processes
Universität Würzburg, Germany
Models for interface growth and surface wetting in stationary states far from equilibrium are particularly interesting candidates for the study of entropy production and the distribution of fluctuations. The talk starts with an introduction to the theory of entropy production and fluctuation relations, applying these concepts to a restricted solid-on-solid model for interface growth. Moreover, we address the question under which conditions time-integrated currents different from the environmental entropy may exhibit a Gallavotti-Cohen symmetry. As an example for such a time-integrated current we study the interface height of a KPZ growth process in finite systems.
Collective behavior of Molecular Motors
T. Guerin, J. Prost, JF Joanny
Institut Curie, France
In this talk, we discuss the collective behavior of assemblies of molecular motors and in particular the dynamic instabilities and the oscillations that they can generate. We first discuss the spontaneous oscillations observed in so-called motility assays by the group of P. Martin using the two-state rigid motor model of J. Prost and F. Julicher We then propose a two-state ``soft-motor'' model for the collective behavior of molecular motors which takes into account both the internal motor stiffness and the periodic interaction with the filament. Dynamic instabilities associated with negative friction occur in the two different limits of very rigid and very soft motors. These limits correspond to the two existing theories of motor assemblies, the rigid two-state model and the crossbridge model. Finally we discuss the bidiretional motion of a motor assembly. We calculate the first passage time for the revesal of the velocity of the motors and show that it incresases exponentially with the number of motors.
Physics of topological excitation in Bose-Einstein condensates
University of Tokyo, Japan
When a system having some symmetry loses it to lower symmetry,
topological excitations can come into existence, depending on how
the symmetry is broken. Topological excitations exist in various kind of
systems and have studied in many field of physics such as cosmology,
elementary particle physics, solid state physics, soft matter physics,
and so on.
Geometry dependence of Fluctuation-induced forces
Laboratoire de Physico-Chime Théorique, France
Ever since the work of Keesom and London it is has been known that both
thermal and quantum fluctuations give rise to long-ranged interactions
between atoms. These fluctuations are best understood through Lifshitz
theory, which links their strength to the dielectric
properties of media.
Phases and phase transitions of spin 1 bosons
Indian Institute of Science, India
Condensates of bosons with spin have been realised in the laboratory over the last decade and have been attracting a lot of interest. In addition to superfluid order, it is possible for these systems to also have magnetic order arsing from interactions between the spin degrees of freedom. The resulting ordered state manifolds and topological defects can be quite complex resulting in exotic phase transitions. In this talk, I will focus on the classical and quantum phase transitions that systems of bosons with spin 1 can undergo highlighting the role of topological defects. In one dimension at a filling on one boson per site, it will be shown that strong correlations on a lattice can result in a dimerized phase which can then give way to a paired superfluid upon increasing charge fluctuations. With two bosons per site, I will argue that it might be possible to have a topologically ordered Mott phase.
Nucleation and proper organization of Golgi apparatus proceeds via overlapping pathways of centrosomal and Golgi microtubules
Raja Paul (a), Paul M. Miller (b), Irina Kaverina (b) and Alex Mogilner (c)
(a) Department of SSP, I.A.C.S., India.
(b) Department of Cell and Developmental Biology, Vanderbilt University Medical Center, USA.
(c) Department of Mathematics, University of California, USA.
Dynamics of adaptation in constant and changing environment
Universita' "Federico II", Italy
I shall review recent approaches to the dynamics of adaptation in haploid populations, in both constant and changing environments, on the one hand making connections with several ongoing evolution experiments, and highlighting on the other hand the intriguing connections with nonequilibrium statistical mechanics.
From simple self-propelled particle models to collective motion in bacteria
Max Planck Institute for the Physics of Complex Systems, Germany
I will start by reviewing the most relevant results obtained in minimal self-propelled particle models to finally focus on recent experiments with Myxococcus xanthus. I will argue that the active motion of bacteria combined with volume exclusion effects of their rod-shaped cell body is sufficient to induce collective motion and a rich clustering dynamics. Moreover, this argument suggests the existence of universal clustering properties in bacteria. I will show that the experimental evidence supports this view.
Record Statistics of Continuous Time Random Walk
Raman Research Institute, India
Record Statistics of Continuous Time Random Walk Abstract: In this talk, I will discuss the statistics of records. In particular analytical results would be presented for that of a correlated time series generated by a continuous time random walk.
Generalized Jarzynski Equality under Nonequilibrium Feedback Control
Takahiro Sagawa (a) and Masahito Ueda1 (b)
(a) Department of Physics, University of Tokyo
(b) ERATO Macroscopic Quantum Control Project, Tokyo, Japan
An exact solution for the 1D KPZ equation
Chiba University, Japan
The Kardar-Parisi-Zhang (KPZ) equation is a nonlinear stochastic
differential equation which describes surface growth.
We consider the one-dimensional version of the equation with
sharp wedge initial conditions. Starting from a basic introduction,
we explain a few properties of the equation. Then we show that the
distributions of the height is written as an integral of a Fredholm
Collapse and Revival of Quantum Correlations in a Quantum Spin Chain
Aditi Sen De
Harish-Chandra Research Institute, India
The properties of quantum many-body systems can have both quantum and classical characters. These properties are generally governed by correlations that are present between the parts of the system. The nature of the correlations thus holds the key in the understanding of nonclassical phenomena such as quantum phase transitions, decoherence, and in various applications of quantum information theory. The recently achieved unprecedented levels of control of parameters in engineering many-body systems in ultracold gases, offer exciting possibilities of realization, understanding, and commercial usage of such phenomena. We will discuss about the recent proposal of approaching such quantum many-body phenomena by studying the dynamics of entanglement and other quantum correlations in such systems. In particular, we will tell you about a phenomenon of collapse and revival of entanglement with respect to a transverse time-dependent field in the quantum anisotropic XY spin chain.
Fluctuation relation for sheared micellar gel and colloidal glass
A.K. Sood and S. Majumdar
Indian Institute of Science, India
First -Principle Derivation of Entropy Production in Transport Phenomena
Tokyo University of Science, Japan
Non-adiabatic quench dynamics near anisotropic quantum critical points
Aoyama-Gakuin University, Japan
Following the development in cold atom experiments, non-equilibrium
quantum dynamics induced by a quench of a parameter in system have
received a lot of attention. In particular, the dynamics following
a slow quench of a parameter across a quantum critical point is an
alluring topic. Supposing that the system is in the ground state
initially, a slow quench of a parameter makes the system in excited
state and the number of elementary excitations is expected to by
scaled by the quenching rate.
Quantum phase transitions and dynamical correlations in spin-glass systems
Tokyo Institute of Technology, Japan
We study effects of random fluctuations on quantum phase transitions at zero temperature. For the Sherrington-Kirkpatrick model with a transverse field, we find that a strong sample-to-sample fluctuation effect leads to a broad distribution of the energy gap. As a result, the spin-glass, and nonlinear susceptibilities diverge at different points. We also study imaginary-time dynamics to understand the mechanism of the transition.
Phase Transition of Generalized Ferromagnetic Potts Model -- Effect of Invisible States
Shu Tanaka, Ryo Tamura, and Naoki Kawashima
Kinki University, Japan
Noise propagation in biochemical networks
Department of Physics, Hong Kong Baptist University, Hong Kong
Role of loop dynamics in thermal stability of proteins
Indian Institute of Mathematical Science, India
Enzymes from thermophiles are poorly active at temperatures at which their mesophilic homologs exhibit high activity. The structures of thermophilic enzymes can have restricted mobility at temperatures optimum for their mesophilic homologs. Here, we present results from molecular dynamics (MD) and normal mode analysis on AdSS enzyme from E. coli (mesophilic) and P. horikoshi (thermophilic) organisms to understand the nature of loop/protein dynamics in enzyme catalysis. We also address issue of relationship between flexibility and rigidity and its role on protein structure-function conservation at elevated temperatures.
Huge-scale molecular dynamics simulation on bubble-nucleation phenomena
The Institute for Solid State Physics, The University of Tokyo, Japan
While gas-liquid multi-phase flow plays quite important role in heat engines such as power plants, it is difficult to study both by theoretically and numerically because it is multi-scale and multi-physics system. Especially, creation and annihilation of phase boundaries make simulations difficult. Recently, we developed a parallel molecular dynamics (MD) simulation code which is scalable up to ten thousand processes. Huge scale MD simulations allow us to study multi-scale and multi-physics systems directly. In this talk, we report how to achieve huge-scale simulations on massively parallel computers and give some recent results of our study on bubble nucleation.