We consider a quantum system of non-interacting fermions at temperature T in the framework of linear response theory. We show that semi-classical analysis is an appropriate framework to describe some of their thermodynamic properties, in particular through asymptotic expansions in the Planck constant of the dynamical susceptibility. We show how the closed orbits of the classical motion in phase space manifest themselves in these expansions, in the region of low temperature.

For last couple of months the story of the Large Hadron Collider (LHC), its success,its perceived failure and associated fear has permeated both the popular and the scientific news. In some quarters while it is being touted that the LHC will answer all the possible mysteries of the Universe, in another section of press it is being said that the LHC will eventually lead to the destructionof the Universe.In this talk I will present the status of the Large Hadron Collider (LHC)machine at the European Organization for Nuclear Research (CERN), Geneva,Switzerland and one of the the two multipurpose detectors, the Compact MuonSolenoid (CMS) meant to record proton-proton collision at a center of massenergy of 14 TeV. I will also give a brief review of first physics resultsthat are expected with the CMS detector at the LHC.

Our highly industrialized society is always in search of ways to reduce or control friction and wear of materials. Diamond coatings can provide an efficient solution for these problems. The focus of this research work is to study the potential of diamond coatings to improve the tribological properties of steel components. Although chemical vapour deposition (CVD) of diamond is well researched and well established on various non-diamond substrates, deposition on ferrous materials is difficult to obtain and not yet up to the stage of commercial realization. One of the main challenges associated is that iron comes under the group VIII transition metals and due to their partially filled 3d orbital, Fe atoms are highly reactive towards carbon. On the other hand, carbon also has a high coefficient of diffusion in the iron matrix. As a result, the incubation time to reach the critical carbon concentration is very long for steel substrates. Another major drawback is the thermal expansion coefficient mismatch between steel and diamond, which results in high thermal stresses upon cooling, leading to poor adhesion. Using various interlayer and surface pretreatment techniques, we have overcome the above mentioned problems and successfully obtained diamond coatings on steel substrates by hot filament chemical vapour deposition (HFCVD) technique. Tribological characterization of the diamond coated steel substrates was performed under small amplitude oscillatory motions, known as fretting. In this talk, an overview of the diamond CVD mechanism, challenges, interlayer systems and the fretting wear behaviour of the diamond coatings will be presented.

Pine, Chaikin and collaborators [Nature (2005), Nature Physics (2008)]have recently studied the transition between reversible andirreversiblebehavior in a simple experiment. The experiment consists of observingand studying the trajectories of a large number of particles suspendedina fluid sheared between two coaxial cylinders. These experimentsillustrate a novel way in which a driven many-particle system canself-organize (termed“random organization” by these authors). They also illuminateseveral problems which lie at the foundations of statisticalmechanics, such as theconnection between irreversible behaviour at the macroscopic scale andmicroscopic reversibility at the microscale.I will first describe these experiments and then present a simplemodel for the underlying physics. Predicting universal features of thereversible-irreversibletransition seen in these experiments then becomes possible. Thesepredictions are in reasonable agreement with what is seen in theexperiments. I will also brieflydescribe the connection to recent ideas concerning the “jamming”transition in granular materials, ideas that may have broaderimplications for theories of the glasstransition.

Driven diffusive systems are generically out of equilibrium. Iwill consider two paradigmatic examples, the asymmetric simple exclusionprocess and the zero-range process. I will discuss size effects on thebehavior of fluctuations in the nonequilibrium stationary state of these twoprocesses on a one-dimensional periodic lattice of finite size. Theexclusion process involves hard core particles executing biased diffusionwith a constant rate. In the zero-range process, particles perform biasedhopping between sites with a rate which depends on the occupancy at thedeparture site. In the stationary state, this process shows a phasetransition as a function of the particle density, from a low-densitydisordered phase to a high-density condensed phase. In both these processes,size effects interplay with the nonequilibrium dynamics to bring in richdynamical phenomena otherwise absent in equilibrium.