High Energy PhysicsHigh Energy Physicsat IIT Kanpur

What is High Energy What is High Energy Physics?Physics?

QuestionsQuestionsWhat are the elementary

constituents of matter?What is the fundamental theory

of nature? What is space-time?What is the Universe?How did the Universe originate?

We don’t just day-dream We don’t just day-dream to find out the answersto find out the answers

ObservationsObservations

WMAP Satellite WMAP Satellite ObservatoryObservatory

Areas of ResearchAreas of ResearchQuantum Field TheoryQuantum ChromodynamicsQuark Gluon PlasmaLattice Gauge TheoryStandard Model of Particle Physics Non-local Field TheoriesCausality Violation in Field TheoriesHigh Temperature Quantum Field

TheoryPhysics Beyond the Standard Model

Areas of ResearchAreas of ResearchString TheoryD-Branes Black Hole Physics and Thermodynamics CosmologyCosmic Microwave Background RadiationAstrophysics and Cosmic RaysQuantum Computation and

EntanglementScanning Tunneling Microscope (STM)

Faculty MembersFaculty MembersDipankar ChakrabartiKaushik BhattacharyaTapobrata SarkarGautam SenguptaSatish D. JoglekarDeshdeep SahdevV. RavishankarPankaj Jain

Ph.D. StudentsPh.D. StudentsAnurag Sahay Ravindra Kumar Asrarul HaqueNaveen Kumar SinghPavan K. AluriBithika JainPrabwal Joti PhukonSubrajyoti AdhyaGopalPrabhakar TiwariPranati Kumari Rath

Dipankar ChakrabartiDipankar ChakrabartiPh.D., SINP, 2004Quantum Chromodynamics (QCD), Lattice Gauge Theory and Lightcone Field Theories

Kaushik BhattacharyaKaushik BhattacharyaPh.D., SINP (Jadavpur), 2005Quantum Field Theory, Standard Model, Astrophysics, Cosmology

Lee-Wick Quantum Field Lee-Wick Quantum Field TheoriesTheoriesIt is postulated by many authors that

all the Standard Model fields have a much heavier partner whose presence makes the theory unstable.

These partners are supposed to decay to give normal Standard Model fields at present.

We aim to investigate whether we can make a stable thermodynamic description of the very early universe with these so called Lee-Wick partners.

Application of quantum field Application of quantum field theory in Astrophysics theory in Astrophysics decay of neutrinos into a charged

lepton and the W-boson in presence of a magnetic field.

calculate to one-loop the self-energy of the neutrino in presence of a uniform magnetic field which affects the behavior of the charged leptons and the W-boson.

We noted that the decay probability is highly affected by strong magnetic fields.

electron in presence of an electron in presence of an external uniform classical external uniform classical electric fieldelectric field

Can be cast in two ways: electric field enters the Schrodinger eqn through a purely time dependent gaugeelectric field enters the Schrodinger eqn through a purely coordinate dependent gauge

We showed that gauge transformation in this case can be mimicked by two coordinate transformations, one from the lab-frame to the frame of the accelerated electron and the other from the electron’s frame to the lab-frame.

Other Current Research Other Current Research InterestsInterestsCP-violation in presence of a thermal

medium and a magnetic field some properties of the Lorentz

group. Aims to see the mathematical

properties of the subgroups of the Lorentz group and how velocity addition rules are implemented in the various subgroups of the Lorentz group.

[1] Causality Violation and its experimental Detection[1] Causality Violation and its experimental Detection[2]1+1 dimensional Yukawa model and bound states[2]1+1 dimensional Yukawa model and bound states[3]effective field theory from Yukawa model and causality[3]effective field theory from Yukawa model and causality

S.D. Joglekar

Ph.D., Stony Brook, 1975

When high enough energies are probed at LHC, new physics may show up. Various forms of new physics have been contemplated.

One possible modification that does not involve new physics directly is, say, presence of fundamental length scale and consequently a non-local structure of interactions at a very small scale.

Thus, Non-locality of interaction could be due to an underlying space-time structure [space-time granularity, non-commutative space etc.] or composite structure of Standard model particles.

The objective is to show that causality violation (CV) can be tested in the usual lab experiments.

We use the Kleppe-Woodard-Moffat nonlocal field theory as a model that embodies a scale .

We use Bogoliubov causality and show that nonvanishing matrix elements of

Can signal CV.We show that [A.Haque,SDJ JPhys 2008]

can put bound on This work is generalized to experimentally measurable

processes e+e-e+e-,

We show that

It is shown that 1+1 dimensional Yukawa model gives rise to an effective PHI_3 nonlocal QFT as g,M∞ with g3M-1=const

The result is interpreted in terms of bound states in Yukawa theory: there is only one stable bound state in this limit; others become highly unstable.

The effective QFT can be identified with that of the bound state. NonlocalityCV

V RavishankarV Ravishankar

Interests:Quantum Informationo Entanglement o Algorithmso Decoherence in open quantum systemso Control and preparation of Entangled states

Quantum Hall Effects: Integer and FractionalQuark-Gluon-Plasma [Only this will be presented]

Ph.D. (University of Mysore 1987)

Qurk-Gluon Plasma(QGP)Qurk-Gluon Plasma(QGP)

QGP Interests: Quasi-particle description of QCD at high

temperature

Response functions – Debye Screening

Flow parameters (shear & bulk viscosities)

Quasi-particle description of Quasi-particle description of QCD at high temperatureQCD at high temperature Hot QCD equations of state (either improved

pQCD or Lattice) can be realized in terms of effective quasi-partons having non-trivial dispersion relations.

The description is in the spirit of Landau theory of Fermi liquids.

The description yields lattice equation of state for high temperature QCD remarkably well – Ideal gas with effective fugacity

Response functions: Chromo-Response functions: Chromo-electric permittivity for QGPelectric permittivity for QGP

(Ideal gas of quarks and gluons)

For interacting system of gluons and quarks (Lattice EOS) the chromo-electric permittivity posses similar mathematical structure with renormalized charges

The response functions can be employed to study the Debye screening in hot QCD medium

Flow parameters: The shear Flow parameters: The shear viscosity QGPviscosity QGP

The shear viscosity to entropy ratio, (measure of interaction) can take values relatively lower than the proposed bound from AdS/CFT studies (~0.08)

Interactions significantly lower the shear viscosity as compare to its ideal counter part

/ s

Shear viscosity for lattice EOS relative to Ideal EOS

Shear viscosity to entropy ratio as a function of temperature

CollaboratorsCollaboratorsSudhansu Shekhar Mandal;

Gouranga Nayak; Gouranga C Nayak; Akhilesh Ranjan; Vinod Chandra; Ravindra Kumar; Ambar Jain; Shanthanu Bhardwaj;R S Srikanth; Subhashish Bannerjee; S N Sandhya; DDB Rao; Subrahmanyam

Tapobrata SarkarTapobrata SarkarPh.D. IMSC 2001String Theory and Quantum Gravity

Dimer Models and Quiver Dimer Models and Quiver Gauge TheoriesGauge Theoriesdimer models are naturally related to

closed string theories on non compact orbifolds of complex manifolds of dimensions 2, 3

We have used this new formalism to study the combinatorics of a class of unstable orbifolds

String Theory, Black Hole String Theory, Black Hole Thermodynamics and Brane Thermodynamics and Brane WorldsWorldsWe have investigated the geometry

of the thermodynamic state space of a general class of BTZ black holes

It was shown that the thermodynamic geometry is flat for both the rotating BTZ and the BTZ Chern Simons black holes in the canonical ensemble

further investigated the inclusion of thermal fluctuations to the canonical entropy of the BTZ Chern Simons black holes

Closed String Tachyon Closed String Tachyon Condensation and GLSMsCondensation and GLSMsstudied some aspects of Gauged Linear

Sigma Models corresponding to two and three fold orbifold singularities for generic non cyclic groups

computed expressions for the multi parameter sigma model Lagrangians for these orbifolds, in terms of their toric geometry data

Using this, we have been able to make some very general comments on aspects of the phases of generic orbifolds of dimensions two and three, relevant for string theory

Recent PublicationsRecent Publications T. Sarkar, On Dimer Models and Closed String Theories, JHEP 10

(2007) 010 P. Agarwal, P. Ramadevi, T. Sarkar, A Note on Dimer Models and

D-brane Gauge Theories, JHEP 06 (2008) 054 T. Sarkar, G. Sengupta, B. N. Tiwari, On the thermodynamic

geometry of BTZ black holes, JHEP 11 (2006) 015. Tapobrata Sarkar, Gautam Sengupta, Bhupendra Nath Tiwari,

Thermodynamic Geometry and Extremal Black Holes in String Theory, JHEP 10 (2008) 076.

Anurag Sahay, Tapobrata Sarkar, Gautam Sengupta, Thermodynamic Geometry and Phase Transitions in Kerr-Newman-AdS Black Holes, ArXiv : 1002.2538 [hep-th] (submitted)

Anurag Sahay, Gautam Sengupta, JHEP 0706 (2007) 006 Tapobrata Sarkar, On Tachyons in Generic Orbifolds of C**r and

Gauged Linear Sigma Models, JHEP 0702 (2007) 025 Tapobrata Sarkar, Ajay Singh, On Phases of Generic Toric

Singularities, JHEP 0712 (2007) 021

Gautam SenguptaGautam SenguptaPh.D., IOP, Bhubaneswar, 1992String Theory & Quantum Gravity

Recent PublicationsRecent PublicationsThermodynamic Geometry and Phase

Transitions in Kerr-Newman-AdS Black Holes, Anurag Sahay, Tapobrata Sarkar, Gautam Sengupta, arXiv:1002.2538 

Thermodynamic Geometry and Extremal Black Holes in String Theory, Tapobrata Sarkar, Gautam Sengupta, Bhupendra Nath Tiwari, JHEP 0810:076,2008

Brane World Black Rings, Anurag Sahay, Gautam Sengupta, (Indian Inst. Tech., Kanpur) JHEP 0706:006,2007

On the thermodynamic geometry of BTZ black holes, Tapobrata Sarkar, Gautam Sengupta, Bhupendra Nath Tiwari, JHEP 0611:015,2006

Pankaj JainPankaj JainPh.D. Syracuse Univ. 1988QCD, Standard Model, Cosmology, Astrophysics

Universe is Not IsotropicUniverse is Not IsotropicRadio wave polarizations from distant

radio galaxiesVisible polarizations from distant

quasarsCMBR dipole, quadrupole and octopole

Galaxy distribution and cluster peculiar velocities also show anisotropy

Indicate a preferred direction pointing towards Virgo cluster of galaxies

The Virgo Alignment

quadrupoleand octopole

dipoleradio

optical

Cosmic Microwave Background Cosmic Microwave Background RadiationRadiationWe developed a model independent

method to analyze the CMBR dataWe solved the problem of low

quadrupole power: its extraction from data is biased

Standard Model with Local Standard Model with Local Scale InvarianceScale InvarianceWe proposed a scale invariant

model of fundamental physicsAll mass scales are generated by

the expansion rate of the universe

The theory predicts absence of Higgs from particle spectrum

Cosmic Rays at GRAPES 3Cosmic Rays at GRAPES 3

Deshdeep SahdevDeshdeep SahdevPh.D., Case Western, 1979

Ambient Air OperationnanoREV Table Top STM

Atomic Resolution ImagesBi2Te3