Sedimentation, trapping and up-stream swimming in a model active suspension.
Ronojoy Adhikari
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-dissipation in out of equilibrium systems
Sergio Ciliberto
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.
In the first part of the talk we will describe an experimentin which the modified fluctuation-dissipation-theorems for non-equilibrium steady state, which have been recently theoretically derived, are tested by studying the position fluctuations of a colloidal particle, whose motion is confined in atoroidal optical trap. The role of the statistical error is discussed.
In the second part of the talk we will describe an experiment,where an AFM tip is driven in a steady out equilibrium by random force. We study the applications of fluctuations theoremas a function of the ratio of the variance of the external force with respect to the fluctuations induced by the thermal bath.

Dynamics of a flexible polymer in shear flow
Dibyendu Das
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.

Large deviation functions and fluctuation theorems in heat transport.
Abhishek Dhar
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.
Amit Dutta
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:
(i) the fidelity susceptibility shows an oscillatory behavior.
(ii) the scaling of the maximum of the fidelity susceptibility is given in terms of dynamically generated path dependent "quasi"-critical exponents which otherwise do not show up in describing the quantum critical behavior.
We use a transverse XY spin chain to establish the general scaling theory and connect our results to the scaling of the defect density following a multicritical quantum quench.
References: 1. V. Mukherjee and A. Dutta, arxiv:1006:3342 (EPL (in press))(2010).
2. V. Mukherjee, A. Polkovnikov and A. Dutta, ariv: 1010.4446 (2010)

Explosive percolation: a numerical analysis
Santo Fortunato
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.

Entropy production and fluctuation relations for KPZ growth processes
Haye Hinrichsen
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
Michikazu Kobayashi
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.
As an example, I talk about topological excitation in Bose-Einstein condensates, which enables many kinds of topological excitations to exist, like quantized vortices, monopoles, Alice rings, skyrmions, Hopf links, vortons. I also talk about some dynamical properties of topological excitations and how this study is applied to other kinds of topological excitations in other systems like soft matter physics.

Geometry dependence of Fluctuation-induced forces
Anthony Maggs
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.
Recently the field has been stimulated by high precision experiments looking for mesoscopic non-electrodynamic forces, by applications in building micro-mechanical devices as well as interpreting force microscopy experiments.
In order to apply Lifshitz theory in general geometries we have developed a series of analytical and numerical approximations which we will present.

Phases and phase transitions of spin 1 bosons
Subroto Mukerjee
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.

Dynamics of adaptation in constant and changing environment
Luca Peliti
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
Fernando Peruani
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
Sanjib Sabhapandit
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.

An exact solution for the 1D KPZ equation
Tomohiro Sasamoto
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 determinant.
We discuss a few properties of the solution. In the long time limit it tends to the GUE Tracy-Widom distribution. The first order correction is of t^{-1/3} which is consistent with a recent experiment of liquid crystal turbulence. We also explain the derivation of our results based on the contour integral formula for asymmetric simple exclusion process(ASEP) by Tracy and Widom.

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.

Non-adiabatic quench dynamics near anisotropic quantum critical points
Sei Suzuki
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.
We will present our result on a slow quench dynamics of the ordered and disorderd Kitaev models. Using an exact solution, we found novel scaling laws of the density of excitations and residual energy after the quench for ordered Kitaev model. They are explained by taking anisotropic nature of the quantum critical point into account. On the basis of this observation, we made new scaling formulas for generic anisotropic critical points. For the disoreded Kitaev model, we also found scaling laws of the density of excitations and residual energy. They are explained qualitatively by knowing a nature of the critical point in the disordered system.

Quantum phase transitions and dynamical correlations in spin-glass systems
Kazutaka Takahashi
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.

Role of loop dynamics in thermal stability of proteins
Satyavani Vemparala
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
Hiroshi Watanabe
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.