Abstract

Neutrinos, “the most tiny quantity of reality ever imaginedby a human being”, as quoted by its co-discovererFrederick Reines, never ceased to puzzle physicists.Wolfgang Pauli introduced neutrino in 1930 as a desperateremedy to save the “law of conservation of Energy”. It thentook twenty seven long years to find the first experimentalevidence for its existence. The reason for this long wait isits extreme reluctance to interact with matter. Neutrino canpass through the earth, the sun or other astrophysical objectswithout much interaction. They interact at the best onlyone time over one billion in the huge apparatus built to detectthem. This particular property of neutrino however turnsout to be a blessing in disguise as it opens up a new windowto look at the interior of sun and other astrophysical objects.Over the last several decades, dedicated neutrino experimentsaround the globe have looked for neutrinos from the sun, fromouter space, from interior of the earth and from man made activities.These experiments have answered many of the questions relatedto particle physics, astrophysics and even geophysics.India has a long tradition in neutrino physics. In fact, the firstever cosmic ray produced neutrino was detected in an experimentin the deep mines of Kolar Gold Fields in 1965. India is againplanning to setup an experiment called India-Based NeutrinoObservatory (INO) to study some of the properties of neutrinos.In this talk I will describe few of these experiments and theirfindings. I will also discuss the INO experiment and its physicspotential.

Abstract

If the recently discovered new boson is confirmed to be a Higgsboson, thenstability of the electroweak vacuum in a minimal model with a universalextra dimension (mUED) willrequire a much lower cutoff for the theory than has been envisaged earlier.We show that this lowcutoff leads to important changes in much of the mUED phenomenology studiedtill now. In particular, prospects for LHC searches for n = 1, Kaluza Kleinstates are ratherlimited if conventional search strategies are used. We propose some newmethods which can overcome these difficulties.

Abstract

The understanding of Transition metal (Mn) impurity on semiconductingsurface have opened a wide scope of investigation based on the localstructure, hybridization effect, electronic properties and magneticordering occurring on the surface/interface of the system. The preparedsurface/ interface has been probed in-situ by X-ray photoemission (XPS),X-ray absorption (XAS) and the resonant photoemission (ResPES)spectroscopies along with the parameterized configuration integration (CI)models to calculate the Mn spectral weight in core-level and valence bandphotoemission. Presence of electron correlation has been evident by anintermediate state in the process of photoemission channel. Change of thelineshape due to the transition from an overall N – 1 electron final state(RRAS channel) to an N -2 electron final state (normal Auger channel) isevidenced by the analysis of the experimental data, which also allowed theratio to be tracked between charge delocalization and core-hole timescales as the photon energy is tuned across the Mn L3 edge [1].This can beused as an analysis technique for presence of electron correlation intransition metal based inorganic system. In addition to this, angleresolved photoemission spectroscopy (ARUPS),a powerful technique has beendone for experimental band mapping to detect the evolution of surfacestates below the Fermi energy or Mn derived state crossing the Fermi edgeof the Mn:Ge(111) sample [2]; as compared to the calculated band structureby Density functional theory using LDA[4]. In the second section adescription will be given on the cation diffusion and hybridizationeffects at the Mn-GaSe(0001) interface probed by soft X-ray electronspectroscopies[3]. In all the above systems, magnetic properties have beenrevealed as characterized by SQUID magnetometer.References1. Tracking the excitation dynamics in the Mn:Ge(111) metallic interface by resonant electron spectroscopy, L. Sangaletti, *S. Dash*, A. Verdini , L. Floreano, A. Goldoni, G. Drera, S. Pagliara, A. Morgante, J. Phys.: Condens. Matter 24 (2012) 2355022. Angle resolved UV Photoemission study on Mn:Ge (111) surface, *S. Dash*, L Sangaletti, L petaccia et. al. in preparation3. Cation diffusion and hybridization effects at the Mn-GaSe(0001) interface, *S. Dash*, G. Drera, E. Magnano, F. Bondino, P. Galinetto, M.C. Mozzati, V. Aguekian, and L. Sangaletti to be submitted4. First-principles characterization of ferromagnetic Mn5Ge3 for spintronic applications, S. Picozzi and A. Continenza, A. J. Freeman

Abstract

In the last couple of decades a theory has been developed byVasiliev to consider interacting theories of fields with spin greater than2 which is known as higher-spin gravity. This theory has received a lot ofattention recently in the context of AdS-CFT correspondence. The theory invarious dimensions is conjectured to be dual to well known conformal fieldtheories in the boundary. In the light of this recent development, we willdiscuss the higher-spin analogue of topologically massive gravity in threedimensions, which we call topologically massive higher-spin gravity. Wewill start with a brief introduction and motivation to consider higher-spintheories. This will be followed by a brief introduction and overview ofcurrent results in higher-spin theories and topologically massive gravity.This will be followed by our work on topologically massive higher-spingravity. We will discuss various semi classical as well as quantum resultsof the theory considered by us.

Abstract