
Raju, Avinash
This dissertation consist of three parts. The first part of the thesis is devoted to the study of gravity and higher spin gauge theories in 2+1 dimensions. We construct cosmological solutions of higher spin gravity in 2+1 dimensional de Sitter space. We show that a consistent thermodynamics can be obtained for their horizons by demanding appropriate holonomy conditions. This is equivalent to demanding the integrability of the Euclidean boundary CFT partition function, and reduces to GibbonsHawking thermodynamics in the spin2 case. By using a prescription of Maldacena, we relate the thermodynamics of these solutions to those of higher spin black...

Kaviraj, Apratim
Conformal Field Theories (CFT) are Quantum Field Theories characterized by enhanced (conformal) symmetries. They are interesting to Theoretical Physicists because they occur at critical points in phase transitions of various systems and also in the world sheet formulation of String Theory. CFTs allow Operator Product Expansion (OPE) in their correlators. The idea of Conformal Bootstrap is to solely use the conformal symmetries and crossing symmetry in the OPE to solve a conformal led theory and not explicitly use a lagrangian. Solving a CFT is equivalent to obtaining the anomalous dimensions and OPE coe client’s of the operators. The work presented...

Mendiratta, Gaurav
The Standard Model (SM) of particle physics provides the theoretical framework to describe the fundamental interactions among elementary constituents of matter. SM is supported by experiments to a high degree of accuracy, up to parts permil for the electroweak (EW) sector and partspertrillion for QED alone, but it still remains incomplete. Many observed phenomena lack explanation in the framework of the SM and its particles. They indicate the possibility of existence of particles and interactions beyond the SM (BSM). These phenomena include dark matter (DM), dark energy and baryonic asymmetry of the universe. In addition, a quantum description of gravity...

Deb, Oindrila
Topological phases of matter represent a new phase which cannot be understood in terms of Landau’s theory of symmetry breaking and are characterized by nonlocal topological properties emerging from purely local (microscopic) degrees of freedom. It is the nontrivial topology of the bulk band structure that gives rise to topological phases in condensed matter systems. Quantum Hall systems are prominent examples of such topological phases. Different quantum Hall states cannot be distinguished by a local order parameter. Instead, nonlocal measurements are required, such as the Hall conductance, to differentiate between various quantum Hall states. A signature of a topological phase...

Mohan, Kirtimaan A
The nature of interactions of fundamental particles is governed by symmetries. These interactions are well described by an elegant and simple SU(3)c x SU(2)L x U(1)Y symmetric gauge theory that we call the Standard Model (SM) of particle physics. Very recently the CMS and ATLAS experiments at the Large Hadron Collider (LHC) conﬁrmed the discovery of a boson of mass of about 125 GeV. Already, the data collected from these experiments seem to indicate that this particle is in fact the last missing piece and essential ingredient of the Standard Model : the Higgs boson. The Higgs has the very...

Sainadh, U Satya
Many quantum computation algorithms, and processes like measurement based quantum computing, require the initial state of the quantum computer to be an eigenstate of a specific unitary operator. Here we study how quantum states that are eigenstates of finite dimensional irreducible representations of the special unitary (SU(d)) and the permutation (S_n) groups can be efficiently constructed in the computational basis formed by tensor products of the qudit states. The procedure is a unitary transform, which first uses SchurWeyl duality to map every eigenstate to a unique Schur basis state, and then recursively uses the Clebsch  Gordan transform to rotate...

Iyer, Abhishek Muralidhar
The discovery of the Higgs boson by the LHC provided the last piece of the puzzle neces sary for the Standard Model (SM) to be a successful theory of electroweak scale physics. However there exist various phenomenological reasons which serve as pointer towards the existence of physics beyond the Standard Model. For example the explanation for the smallness of the neutrino mass, baryon asymmetry of the universe, the presence of dark matter and dark energy etc. are not within purview of the Standard Model. Con ceptual issues like the gauge hierarchy problem, weakness of gravity provide some of the theoretical...

Chowdhury, Debtosh
The Standard Model of particle physics attempts to unify the fundamental forces in the Universe (except gravity). Over the years it has been tested in numerous experiments. While these experimental results strengthen our understanding of the SM, they also point out directions for physics beyond the SM. In this thesis we assume supersymmetry (SUSY) to be the new physics beyond the SM. We have tried to analyze the present status of low energy SUSY after the recent results from direct (collider) and indirect (flavor, dark matter) searches .We have tried to see the complementarity between these apparently different experimental results...

Soori, Abhiram
This thesis presents the work done on electronic transport in various interacting and noninteracting systems in one and two dimensions. The systems under study are: an interacting quantum dot [1], a noninteracting quantum wire and a ring in which timedependent potentials are applied [2], an interacting quantum wire and networks of multiple quantum wires with resistive regions [3, 4], onedimensional edge stages of a twodimensional topological insulator [5], and a hybrid system of twodimensional surface states of a threedimensional topological insulator and a superconductor [6].
In the first chapter, we introduce a number of concepts which are used in the rest...

Patra, Monalisa
The Standard Model of particle physics which attempts to describe all matter and all forces in the universe (except gravity),has been in agreement with most of the experiments till date. However theoretically and phenomenologically many questions remain unanswered in the SM. The present and future colliders will help the physicists learn more about the nature of matter and all forces in the universe. In this thesis work we have mainly focused on the physics case of the future linear collider which will be a succession of the presently running Large Hadron Collider in CERN Geneva.
As an introduction to the...

Sen, Kallo
The work done in this thesis includes an exploration of both the conformal field theory techniques and holographic techniques of the Gauge/Gravity duality. From the field theory, we have analyzed the analytical aspects of the Conformal Bootstrap program to gain handle on at least a part of the CFT spectrum. The program applies equally to the strongly coupled as well as the weakly coupled theories. We have considered both the regimes of interest in this thesis. In the strongly coupled sector, as we have shown that it is possible to extract information about the anomalous dimensions, of a particular subset...

Arunprasath, V
The Standard Model (SM) of the particle physics, based on the gauge group SU(3) ×SU(2)L × U(1)Y , has been a successful theory which provides consistent description of all phenomena ranging from the nuclear beta decay to known processes at the high energy colliders like the LHC which operates at the TeV scale. Nevertheless, the SM is considered to be only a low energy (weak scale) theory and not a theory that is valid up to an energy scale (∼ 1019 GeV) where the effects of gravity are expected to be strong. The reasons for this view include the sensitivity...

Arunprasath, V
The Standard Model (SM) of the particle physics, based on the gauge group SU(3) ×SU(2)L × U(1)Y , has been a successful theory which provides consistent description of all phenomena ranging from the nuclear beta decay to known processes at the high energy colliders like the LHC which operates at the TeV scale. Nevertheless, the SM is considered to be only a low energy (weak scale) theory and not a theory that is valid up to an energy scale (∼ 1019 GeV) where the effects of gravity are expected to be strong. The reasons for this view include the sensitivity...

Datta, Shouvik
The idea of holography [1, 2] finds a concrete realization in form of the AdS/CFT correspondence [3, 4]. This duality relates a field theory with conformal symmetries to quantum gravity living in one higher dimension. In this thesis we study aspects of black hole quasinormal modes, higher spin theories and entanglement entropy in the context of this duality. In almost all cases we have been able to subject the duality to some precision tests.
Quasinormal modes encode the spectrum of black holes and the timescale of pertur
bations therein [5]. From the dual CFT viewpoint they are the poles of retarded...

Datta, Shouvik
The idea of holography [1, 2] finds a concrete realization in form of the AdS/CFT correspondence [3, 4]. This duality relates a field theory with conformal symmetries to quantum gravity living in one higher dimension. In this thesis we study aspects of black hole quasinormal modes, higher spin theories and entanglement entropy in the context of this duality. In almost all cases we have been able to subject the duality to some precision tests.
Quasinormal modes encode the spectrum of black holes and the timescale of pertur
bations therein [5]. From the dual CFT viewpoint they are the poles of retarded...

Chatterjee, Sandeep
Ultrarelativisitic heavy ion collisions produce quark gluon plasmaa hot and dense soup of deconfined quarks and gluons akin to the early universe. We study two models in the context of these collisions namely, Polyakov Quark Meson Model (PQM) and Hadron Resonance Gas Model (HRGM).The PQM Model provides us with a simple and intuitive understanding of the QCD equation of state and thermodynamics at non zero temperature and baryon density while the HRGM is the principle model to analyse the hadron yields measured in these experiments across the entire range of beam energies.
We study the effect of including the commonly...

Chandra, Nitin
There is a growing consensus among physicists that the classical notion of spacetime has to be drastically revised in order to nd a consistent formulation of quantum mechanics and gravity. One such nontrivial attempt comprises of replacing functions of continuous spacetime coordinates with functions over noncommutative algebra. Dynamics on such noncommutative spacetimes (noncommutative theories) are of great interest for a variety of reasons among the physicists. Additionally arguments combining quantum uncertainties with classical gravity provide an alternative motivation for their study, and it is hoped that these theories can provide a selfconsistent deformation of ordinary quantum field theories at small...

Singh, Ritesh K