04-01-2016 At 04:00:00 PM
Speaker: Professor Jogesh C. Pati , (SLAC, Stanford University, USA)
Category: Colloquium
Venue: Lecture Hall
Progress in physics, of a fundamental nature, has often occurred by finding connections between diverse phenomena, in short by realizing a certain unity in diversity. An accompanying quest for beauty and simplicity in the underlying laws of nature, sometimes guided by experiments, and sometimes just by pure thought, has invariably played the dominant role in providing the clue for such a unity.Starting with examples of such a unification, comprising the path-setting contributions of luminaries like Newton, Maxwell, Einstein, and others, the talk will emphasize especially the idea of a unification of all matter: nuclear and non-nuclear, and simultaneously of the three of their fundamental forces: the nuclear, electromagnetic and the weak-radioactive.The far-reaching consequence of such a unity, commonly called “Grand Unification” in shedding light on the elusive properties of the feeblest and the lightest known massive particles – the neutrinos – will be noted. The accompanying possibility of linking the tiny neutrino masses to a resolution of the mystery of the observed matter- antimatter asymmetry of the universe will be presented. Such an asymmetry is, of course, necessary for the origin of life, and thus for our own existence.Perhaps the most profound consequence of grand unification is the prediction that the lightest observed nuclear particle – the proton – which is known to be extraordinarily stable, must ultimately decay entirely into non-nuclear particles such as antielectrons and mesons, albeit with a very long lifetime, as large as some 10^ 35 years. World-wide efforts (in which India is expected to play a major role) to search sensitively for this extraordinary process will be presented. Discovery of proton decay will constitute a landmark in the history of physics.Time permitting, the talk will end by noting briefly the intimate link that exists between the very large (the cosmos), and the very small – the minutest objects of which we are all made
06-01-2016 At 10:00:00 AM
Speaker: Prof. Rajaram Nityananda, Azim Premji University, Bengaluru
Category: Colloquium
Venue: Lecture Hall
Generalised by Clausius to all thermodynamic systems. After beinggiven a statistical basis by Boltzmann, entropy reappeared as ameasure ofinformation in Shannons mathematical theory of communication which lies atthe basis of much of todays technology. The two apparently distinct kindsof entropy / information turn out to be connected by Maxwells demon and itsdescendants. This talk will go over these themes and their relation toBayesian statistical inference.
11-01-2016 At 11:00:00 AM
Speaker: Dr. Amit Gupta, Banaras Hindu University (BHU), India
Category: CMP Seminar
Venue: Lecture Hall
In this talk, I will discuss the thermoelectric transport in twodimensional topological system which has coexistence ofsuperconductivity(SC) and spin-density wave(SDW). The SC is presumed to beof dx2−y2 + (px + ipy ) type whereas the SDW order parameter is ofBCS symmetry. The Hamiltonian describing such a coexistence phase will beshown to have topological phase in addition to the conventional one. Thetransport properties in such topological system have two distinctcontributions: (i) the surface/edge and (ii) the bulk. The competitionbetween the surface/edge versus the bulk transport is analyzed indifferent parameter regimes and the possibility of enhancing the figure of merit will be discussed.
12-01-2016 At 04:00:00 PM
Speaker: Dr. Amit Sharma , University of Gothenburg, Sweden
Category: CMP Seminar
Venue: Lecture Hall
14-01-2016 At 04:00:00 PM
Speaker: Dr.Jaishri Sanwal,Research Scientist,JNCASR, Benguluru
Category: General Seminar
Venue: Lecture Hall
22-01-2016 At 04:00:00 PM
Speaker: Dr. Moitri Maiti , JINR,Dubna, Russia
Category: CMP Seminar
Venue: Lecture Hall
In this talk I would discuss how superconducting junctions can be used asphase sensitive detectors for Dirac and Majorana fermions. With a briefintroduction to the physics of Dirac like materials, i.e materials whoselow energy excitations obey an effective Dirac equation viz. graphene, Iwould discuss the transport and dynamics in superconducting junctions ofsuch materials. In the second part of the talk, I would discuss dynamicsin a superconducting junction with effective p-wave pairing amplitude andshow that analysis of the current-voltage characteristics reveals robustphase-sensitive signatures for existence of Majorana quasi-particles insuch junctions.
02-03-2016 At 04:00:00 PM
Speaker: Sanjib Sabhapandit, RRI, Banglore
Category: Seminar of General Interest
Venue: Main Lecture Hall
Among the most interesting recent developments in the theory of nonequilibrium processes are so-called fluctuation theorems. These theorems make quantitative statements on the probability of negative entropy production in nonequilibrium systems. I will start with fluctuation theorems and its connections to large deviations. I will then describe how the large deviation function can be evaluated for the heat flow across a harmonic chain. Finally, I will show application of the results to an recent experiment.
10-03-2016 At 04:00:00 PM
Speaker: Dr. K.N. Deepthi,(Hyderabad Central University)
Category: TPSC HEP Seminar
Venue: Lecture Hall
Motivated by the recent data from T2K and MINOS, which show the evidence ofa relatively large theta13 at 3 sigma level, we study the phenomenologicalimplications of the bimaximal mixing (BM), the tri-bimaximal mixing (TBM),and the democratic mixing (DC) matrices with some modifications. Using suchmixing matrices and assuming texture one-zero in the neutrino mass matriceswe have shown whether such mixing matrices satisfy normal or inverted masshierarchy, or phenomenologically viable or not. We have scrutinizedfurther implications of Democratic mixing matrix, motivated by its successin naturally accommodating the nonzero reactor mixing angle theta13. Wehave also explored the possibility of determining the mass hierarchy,octant of the atmospheric mixing angle theta23, and the CP violationdiscovery potential in the current and upcoming long-baseline experimentsT2K, NOvA and LBNE (DUNE).
10-03-2016 At 11:00:00 AM
Speaker: Dr. Subhajit Sarkar , S.N.Bose National Centre, Kolkata
Category: CONDENSED MATTER PHYSICS SEMINAR
Venue: Lecture Hall
In this talk I shall try to convey to you that the interaction betweencollective excitations originating from a strongly anisotropic quantumHeisenberg ferromagnet on two dimensional lattices, can very well lead tothe formation of localized topological excitations of vortex/anti-vortextype. This happens below the Berezinskii-Kosterlitz-Thouless transitiontemperature (𝑇𝐵𝐾𝑇) when vortices andanti-vortices are immobile and remain as bound pairs. I will describe ourconstruction of quantum states of vortex like topological excitationscorresponding to spin-1/2 strongly XY- anisotropic nearest neighbourHeisenberg ferromagnet on two-dimensional lattice. The procedure involvesthe Pauli spin basis states and is carried out corresponding to bothinfinite dilute limit and finite density limit of vortex/anti-vortex. Itis found that the corresponding quantum mechanical states representingcharge 1 quantum vortices/anti-vortices can be expressed as linearcombinations of single magnon states, composite multi-magnon states andthe ground state. Detailed calculations show that these states are quantummechanically stable states of the Hamiltonian provided that the systemsize exceeds certain threshold value. I will further argue that theinteractions between different magnon modes or rather fragile magnon modescan very well generate these topological excitations. Plausibility of ourcalculations in the real magnetic systems shall also be discussed.
11-03-2016 At 04:00:00 PM
Speaker: Dr. Gauhar Abbas ,(Instituto De Fisica Corpuscular, University of Valencia, Spain)
Category: TPSC HEP Seminar
Venue: Lecture Hall
We compute the flavour-changing top decays t -> ch and t -> cV (V =g ,Z)within the framework of the aligned two-Higgs-doublet models. By exploitingconstraints from flavour physics and the measured Higgs properties, weinvestigate the parameter space of the model and its impact on theassociated branching ratios. It is observed that the Higgs signal strengthin the di-photon channel imposes important restrictions on the t -> chdecay rate when the charged scalar of the model is light. We conclude thatthe rates of these flavour-changing top decays are beyondthe expected sensitivity of the future high-luminosity phase of the LHC.
15-04-2016 At 11:00:00 AM
Speaker: Dipanjan Bhattacharya
Category: Seminar of General Interest
Venue: IOP Lecture Hall