Our understanding of orgin of the universe is mainly in frame work of Big-Bang models. Stringent constraints on these models come from light element abundances and thermal evolution of cosmic microwave background. Development of structures in the Universe very much depends on the mass density of different components and their redshift evolution.Development of fundamental physics relies on the constancy of various fundamental quantities such as the fine structure constant. Detecting or constraining the possible time variations of these fundamental physical quantities is an important step toward a complete understanding of basic physics.High quality absorption lines seen in the spectra of distant QSOs allow one to address all the above listed issues. In this talkwe will present the overview of the approach and highlightsome very recent results based on observations taken with VeryLarge Telescope (VLT) in Chile and Giant meterwave radio telescopenear Pune.

We review the long-standing arguments in favor of stable exotic mesons with two heavy quarks and two light antiquarks. For a flavor independent interaction, as suggested by QCD, this mass configuration is favored as compared to equal-mass or hidden-charm configurations, in complete analogy with the pattern observed in atomic physics when the hydrogen molecule is compared to the positronium molecule or to the hydrogen-antihydrogen system.We then present the results of a recent model calculation, inspired by the strong coupling limit of QCD: the linear potential for a quark-antiquark pair in mesons is generalized as a Y-shape interaction for baryons and a Steiner tree for tetraquarks. The four-body problem is then solved by an accurate variational method. An analytic upper bound is also obtained, which confirms the numerical results in the limit of large values for the quark mass ratio.

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.