08-01-2009 At 04:00:00 PM
Speaker: Prof. Raymond F. Bishop, University of Manchester
Category: Seminar of General Interest
Venue: Lecture Hall
complete description of quantum information theory needs to incorporate simultaneously at least three important concepts or principles, namely: (a) quantum entanglement, (b) quantumcoherence versus decoherence (i.e., in the presence of dissipation),and (c) the quantum- classical limit (or quantum-classical interface). We discuss how the concept of quantum phasespace can be enlarged to provide just such a unified and consistent description. Quantum phase-space methods and, especially, such quantum phase-space distribution functionsas the P-, Q-, Wigner and Weyl functions, have played an important role over many years in quantum mechanics and such allied areas as quantum optics. We introduce here in a very fundamental manner a natural hierarchy of extended quantum phase spaces and associated extended distribution functions with the capacity to describe simultaneously both quantum noise and quantum correlations at increasingly higher-order levels. We show further how the extendedphase-space formalism provides valuable insights into the important issue of quantum versus classical correspondence, and also how it has extremely appealing properties for a consistent description of quantum information theory. At the next-to-lowest (x-p-X-P) level in the extendedhierarchy the description of mixed states becomes unified, and a very convenient means is opened up, for example, to discuss together, and on the same footing, the ordinary Wigner and Weyl functions of a quantal system. The doubling of the number of degrees of freedom, which, rather surprisingly, has its roots in classical mechanics, has strong overlaps with a similar feature of thermo-field dynamics, and hence with the treatment of quantum systems subject to thermal noise.
16-01-2009 At 04:00:00 PM
Speaker: Dr. G. Brauer, Forschungszentrum Dresden-Rossendorf, Germany
Category: Seminar of General Interest
Venue: Lecture Hall
nO is of considerable interest for optoelectronic device applications dueto its wide band gap and high exciton binding energy. In spite of decadesof study and recent progress in research on ZnO properties, there remainedunresolved controversies which are mainly related to native defects formedduring crystal growth. Positron annihilation spectroscopy (PAS) is amongthe methods to tackle this structural issue. ZnO nanostructures, like e.g.nanorods and tetrapods, are of special interest for device applications.However, their characterization remains an ongoing challenge. This talkintends to review our recent efforts and latest achievements in thisdirection. Results obtained will comprise PAS in the form of Slow PositronImplantation Spectroscopy (SPIS) and Pulsed Low Energy Positron LifetimeSpectroscopy (PLEPS), Nuclear Reaction Analysis (NRA), Atomic ForceMicroscopy (AFM), conductive AFM (C-AFM), Nuclear Magnetic Resonance(NMR), Electron Spin Resonance (ESR), Photoluminescence (PL) spectroscopy,and latest theoretical investigations of structure-related and positronproperties of selected defects. The fundamental importance of arelationship between fabrication conditions, native defect formation, andresulting optical and electronic properties is demonstrated by gettingeither inferior (nanorods) or significantly improved (tetrapods) opticalproperties compared to single crystal samples, depending on thenanostructure fabrication method.
19-01-2009 At 04:00:00 PM
Speaker: Prof. J.C. Pati, USA
Category: Colloquium
Venue: Lecture Hall
With coupling unification and neutrino oscillation discovered, one can argue that proton decay remains as The Missing Piece of Grand Unification. The colloquium will explain why this is so and will emphasize the importance of improved searches for proton decay in a large Underground detector, which is yet to be built.
22-01-2009 At 04:00:00 PM
Speaker: Prof. Michael Berry, Department of Physics, University of Bristol Tyndall Avenue, Bristol BS8 1TL,
Category: Colloquium
Venue: Lecture Hall
The quantum physics of identical particles is embodiedin the connection between spin and statistics (the Pauli principle).For many decades it has been thought that this can be understood onlywith ideas from relativity and quantum field theory. But in fact itcan be understood in terms of ordinary few-body nonrelativisticquantum mechanics, if this is reformulated to take proper accountof the geometry of the indistinguishability of particles. This canbe made plausible by conjuring tricks with a belt. The 'Pauli sign' (-1)^2Semerges as a geometric phase factor.
22-01-2009 At 03:00:00 PM
Speaker: Dr. V. Venugopal, Department of Physics, University of Genova, Italy
Category: Seminar of General Interest
Venue: Lecture Hall
The study of the growth, structure and thermal stability of an fcc film likeCu on a bcc substrate like Ta is important for understanding heteroepitaxyand for many technological applications. Such a system is vital to study theeffect of lattice and thermal mistmatch between the film and the substrateon defects and thermal stability of the films. Cu/Ta is one of the materialcombinations employed in the current IC-metallization, where Cu is theinterconnect material and Ta is used as diffusion barrier. Ultrathin Cufilms on bcc substrates have been studied as a model bimetallic catalyst.This talk explains the use of thermal helium desorption spectrometry (THDS)to characterize defects and thermal stability of ultrathin Cu films (5-200Å) deposited on Ta (110) and Ta(100) in ultrahigh vacuum (1×10-10 mbar) byelectron beam evaporation. Helium ion energy used is 1000 or 75 eV in orderstudy induced or native defects in the sample. THDS yields information aboutdefects in the subsurface region of a film, down to 10-100 Å below thesurface, depending on the incident helium energy. After collisional slowdownand thermalization, the implanted helium atoms in the sample diffuseinterstitially until they leave the sample or encounter a defect such asvacancies and vacancy clusters where they are trapped. On heating thesample, the helium is released from these defects at temperatures that arecharacteristic of the helium-defect dissociation energies.Some of the salient results that will be discussed are as follows. Heliumrelease from ultrathin Cu films will be compared to bulk Cu. Cu films onTa(110) and Ta(100) at room temperature are metastable and on heating, thefilms transform into islands. The temperature at which this takes place isstrongly dependent on the Cu film thickness and for a given thickness occursat a lower temperature on Ta(100) than on Ta(110). There is evidence for thestressed states of both the Cu films and the Ta substrates. Helium releasefrom monovacancies and vacancy clusters in Cu films on Ta(110) and Ta(100)was detected at ~750 K and ~800-1000 K respectively. The sublimation of theCu films from the Ta substrates could be observed by the release of retainedhelium at ~1300 K.
23-01-2009 At 06:00:00 PM
Speaker: Prof. Michael Berry, Department of Physics, Bristol University
Category: IOP and NISER EVENING LECTURE
Venue: Lecture Hall
Many 'mathematical phenomena' find application and sometimesspectacular physical illustration in the physics of light. Conceptssuch as fractals, catastrophe theory, knots, infinity, zero, and evenwhen 1+1 fails to equal 2, are needed to understand rainbows, twinklingstarlight, sparkling seas, and simple experiments on interference,polarization and focusing, and oriental magic mirrors. The lecturewill be based on pictures (slides and demonstrations), and is nontechnicalyet intellectual.
27-01-2009 At 04:00:00 PM
Speaker: Prof. Eric Bergshoeff,University of Groningen, Netherlands
Category: High Energy Physics Seminar
Venue: Lecture Hall
02-02-2009 At 06:00:00 PM
Speaker: Prof. J.V. Narlikar, IUCAA, Pune
Category: IOP NISER-INSA EVENING LECTURE
Venue: IOP Auditorium
02-02-2009 At 03:30:00 PM
Speaker: Dr. Sudhakar Panda, Allahabad
Category: TPSC HEP Seminar
Venue: Lecture Hall
03-02-2009 At 04:00:00 PM
Speaker: Dr.B. Mukhopadhyaya, HRI, Allahabad
Category: TPSC HEP Seminar
Venue: Lecture Hall
09-02-2009 At 04:00:00 PM
Speaker: Prof. M.K. Pal, Kolkata
Category: Colloquium
Venue: Lecture Hall
Stable nuclei in nature are found within a narrow band of proton and neutron numbers, Z and N respectively. Beyond the domain of these stable nuclei, a large number of nuclei, super-rich in protons for a given N, and super-rich in neutrons for a give Z, have been produced over the last decade or so at several accelerator centres round the world. They are beta active i.e. they decay by positron emission on the high Z side and by electron emission on the high N side and finally end up on the time of stability in the (Z,N) plot of the nuclei. For a given Z a limit to addition of neutrons is reached when the resultant nucleus becomes unstable under particle emission and undergoes a fast decay by neutron emission. The zig-zag line traced by these border-line unstable nuclei on the neutron-rich side is called the neutron-drip line. Similarly, on the proton-rich side one finds a proton-drip line along which the nuclei undergo quick decay by a proton emission. The beta active nuclei on both sides of the region of stability bounded by the two drip lines have measurable half lines, long enough for the study of their systematic properties by state of the art experimental techniques. After a general review of the various experimental features, a brief account will be given of the theoretical work by several groups, including the theory group at IOP, mainly based on the relativistic mean-field formalism. Some of the aspects of the theory, specially related to the treatment of pairing, will be commented upon. My own fairly old work on the two neutron halo will be briefly mentioned.
19-02-2009 At 04:00:00 PM
Speaker: Dr. Anirban Basu, Cambridge University
Category: Seminar of General Interest
Venue: Lecture Hall
20-02-2009 At 04:00:00 PM
Speaker: Dr. Anirban Basu, Cambridge University
Category: HEP Theory Seminar
Venue: Lecture Hall
23-02-2009 At 04:00:00 PM
Speaker: Dr. Abhishek Chaudhuri, RRI, Bangalore
Category: TPSC Seminar
Venue: Lecture Hall
03-03-2009 At 04:00:00 PM
Speaker: Prof. Sumathi Rao, HRI, Allahabad
Category: Seminar of General Interest
Venue: Lecture Hall
We discuss transport through junctions of quantum wiresas an application of quantum field theory methods in low dimensionalcondensed matter systems.
27-03-2009 At 11:00:00 AM
Speaker: Dr. Chethan Gowdigere, HRI Allahabad
Category: High Energy Physics Seminar
Venue: Lecture Hall
31-03-2009 At 04:00:00 PM
Speaker: Dr. Pramoda K. Samal, IIT, Kanpur
Category: TPSC HEP Seminar
Venue: Lecture Hall
We estimate CMB polarization and temperature power spectrum using WMAP5-year foreground contaminated maps. The power spectrum estimation methoddoes not utilize the diffuse foreground templates nor the detector noisemodel. The method essentially consists of two steps, (i) removal ofdiffuse foregrounds contamination by making linear combination ofindividual maps and (ii) cross-correlation of foreground cleaned maps tominimize detector noise bias. For temperature power spectrum we alsoestimate and subtract residual unresolved point source contamination inthe cross-power spectrum by using WMAP's point source model. Our TT, TEand EE power spectra are in good agreement with the published results ofthe WMAP science team. We perform detailed numerical simulations to testfor bias in our procedure. We find that the bias is relatively small forthe TT and TE power spectrum. A negative bias at low l in TT powersepctrum has been pointed in an earlier publication. We find that thenegative bias corrected quadrupole power (l(l+1)C_l/(2*pi)) is 532 microK^2, approximately 2.5 times the WMAP's result (313.4 micro K^2).
01-04-2009 At 04:00:00 PM
Speaker: Prof. D.P. Roy, HCSE, Mumbai
Category: High Energy Group Seminar
Venue: Lecture Hall
02-04-2009 At 04:00:00 PM
Speaker: Dr. Bobby Ezhuthachan, HRI Allahabad
Category: HEP (theory ) Seminar
Venue: Lecture Hall
03-04-2009 At 04:00:00 PM
Speaker: Prof. D.P. Roy, HCSE, Mumbai
Category: High Energy Group Seminar
Venue: Lecture Hall
06-04-2009 At 04:00:00 PM
Speaker: BirBikram Singh, School of Physics and Materials Science, Thapar University, Patiala-147 004
Category: Seminar of General Interest
Venue: Lecture Hall
Heavy ion reaction dynamics has been studied using the Dynamical Cluster-decay Model (DCM) of Gupta and collaborators. DCM have been applied to study the decay of hot and rotating compound systems (i.e. having angular momentum, l ≠0 and temperature, T ≠0). The DCM is a reformulation of Preformed Cluster-decay Model PCM for ground-state decays (i.e. l = 0 and T = 0). Both DCM and PCM are based on Quantum Mechanical Fragmentation Theory (QMFT), first proposed by Gupta and Collaborators at Frankfurt, and then extended at Chandigarh. In DCM, decay of excited compound nuclei is studied as a collective clusterization process for emissions of the light particles LPs (n, p, α) and γ-rays, as well as the intermediate mass fragments IMFs (with 2 < Z < 10 and 5≤A≤20) and the symmetric and near-symmetric mass fragments SF and nSF (20≤A≤A/2), in contrast to the statistical models in which each type of emission is treated on different footing. Another advantage of using the DCM is that the structure effect of compound nuclei (CN) can be addressed via the preformation probability of the fragments, an information missing in the statistical fission models. Keeping in mind the temperature-dependence of collective potential used in DCM, first the temperature-dependent binding energies are calculated, which is an important step in the study of the decay of excited compound systems. The DCM have been applied successfully to study the decay of light (48Cr*) and heavy (202Pb*, 246Bk*) mass nuclear systems formed in different entrance channels at a number of centre-of-mass energies Ec.m.. The role of excitation energy, entrance channel effects together with the effects of deformations and orientations in the fusion-fission process have been investigated extensively. The calculated DCM cross-section for all possible decay paths are found to be in excellent comparison with the available experimental data. Moreover, the possible role of deformed and oriented nuclei in cluster radioactivity has been investigated using the PCM, besides the well established shell effects. For this purpose we have chosen only those cluster decays for which daughter is always spherical and doubly magic (N = 126, Z = 82) 208Pb. The effects of nuclear structure and deformation together with orientations are thus established both in (radioactive) nuclei and excited compound systems via their cluster decay studies.
04-05-2009 At 04:00:00 PM
Speaker: Prof. S.M. Shivaprasad ,JNCASR, Bangalore
Category: Colloquium
Venue: Lecture Hall
Thin Solid films find ubiquitous applications, but among them, the formation of band-gap engineered superlattices and epitaxial self-assembled nanostructures hold great promise in electronics, opto-electronics and catalysis. The need to tailor-make thin films and nanostructures of desired properties has motivated attempts to understand the initial stages of interface formation, since the morphology of the growing film is the result of a delicate interplay of the thermodynamic and kinetic processes involved. Thus, along with the material properties, growth conditions and quantum effects influence the final outcome of the low dimensional structures and their self-assembly. With the advent of ultra-high vacuum technology and surface sensitive probes, several interesting growth phenomena have been revealed at the atomistic level. I shall present my experimental experience of the formation of model systems in the sub-monolayer regime and in-situ characterization by electron spectroscopic, diffraction and imaging techniques. The deterministic role of lattice mismatch, surface free energy, dangling bonds, etc., in the evolution of the interfaces, will be elucidated. The formation of epitaxial self-assembled nanostructures and surface-phases by employing surface morphologies and reconstructions, as templates, will be demonstrated. The role of Edge Barriers and Quantum Size Effects on growth modes in a metal-semiconductor system, will be discussed. Our attempts to chemically modify ultra-thin films for materials related to GaN band-engineering applications will be demonstrated.
20-05-2009 At 04:00:00 PM
Speaker: Dr. Ashok Garai, IIT, Kanpur
Category: TPSC Seminar of General Interest
Venue: Lecture Hall
03-07-2009 At 04:00:00 PM
Speaker: Indranil Chakrabarty, Kolkata
Category: Quantum Information Seminar
Venue: Lecture Hall
08-07-2009 At 04:00:00 PM
Speaker: Mr. Tamal Mukherjee, Bose Institute, Kolkata
Category: HEP Seminar of general interest
Venue: Lecture Hall
We study various thermodynamical variables of importance like quark number susceptibilities, energy density, pressure, specific heat, speed ofsound in the framework of PNJL model as the hadronic system undergoes a phasetransition from the confined to deconfined phase. I will also briefly discussthe extension of PNJL model by incorporating a SU(3) measure to improve thebehaviour of the traced polyakov loop. We make a quantitative comparisonwith the Lattice QCD results. Based On the above study resulting phase diagram will also be discussed.
24-07-2009 At 04:00:00 PM
Speaker: Mr. Syreyas Patankar, KVPY Scholar, Chennai Mathematical Institute , Chennai
Category: Seminar of General Interest
Venue: Lecture Hall
06-08-2009 At 03:30:00 PM
Speaker: Prof. Ashok Das,University of Rochester
Category: High Energy Group Seminar
Venue: Library Lecture Hall
11-08-2009 At 04:00:00 PM
Speaker: Dr. Malay Bandyopadhyay, TIFR, Mumbai
Category: TPSC Seminar of General Interest
Venue: Lecture Hall
In this talk, I will discuss about different aspects ofrotational, translational and quantum Brownian motion in the contextof relaxation dynamics of nano-magnetic particles, diffusion enhancementof a rapidly forced confined Brownian particle, and dissipativediamagnetism respectively. Beside this, I will try to give an overviewon my recent work in the field of quantum thermodynamics and in the fieldof fluctuation driven phase ordering dynamics.
18-08-2009 At 04:00:00 PM
Speaker: Mr. Balakrishnan Subramanian, NIT, Trichy
Category: Quantum Information Seminar
Venue: Lecture Hall
19-08-2009 At 04:00:00 PM
Speaker: Mr. Subhayan Mandal, Physics department, IIT Kanpur
Category: TPSC Seminar of General Interest
Venue: Lecture Hall
Pseudoscalar particles, with almost zero mass and very weakcoupling to the visible matter, are hypothesized in many extensions of thestandard model of particle physics. They mix with photons in presence abackground magnetic field leading to interesting astrophysical andcosmological signatures. This mixing depends on the medium properties, themomentum of the photon and the background magnetic field. Here we give ageneral treatment of pseudoscalar-photon oscillations in a backgroundmagnetic field, taking the Faraday term into account. We predict resultsvalid in all regimes, under the assumption that the frequency of the waveis much higher than the plasma frequency and the gyration frequency of themedium. At sufficiently high frequencies, the Faraday effect is negligibleand we reproduce the standard pseudoscalar-photon mixing phenomenon.However at low frequencies, where Faraday effect is important, the mixingformulae are considerably modified. We calculate the stokes parameters toillustrate this. We also explicitly compute the contribution due to thelongitudinal mode of the photon and show that it is negligible for most ofthe astrophysical application.
20-08-2009 At 04:00:00 PM
Speaker: Prof. Ram Sagar, Director, Aryabhatta Research Institute of Observational Sciences, (ARIES) Nainita
Category: Seminar of General Interest
Venue: Lecture Hall
27-08-2009 At 04:00:00 PM
Speaker: Dr Suvrat Raju, HRI, Allahabad
Category: High Energy Group Seminar
Venue: Lecture Hall
31-08-2009 At 04:00:00 PM
Speaker: Dr Suvrat Raju, HRI, Allahabad
Category: Seminar of General Interest
Venue: Lecture Hall
There is a remarkable similarity between the laws of black hole dynamics and the laws of thermodynamics. One of the great problems of quantum gravity is to understand the entropy of black-holes. String Theory has been successful in accounting for the entropy of several simple black-holes. From a modern perspective, this is a manifestation of the celebrated gauge-gravity correspondence. We will review some of the successes of the theory and conclude with some open questions.
08-09-2009 At 04:00:00 PM
Speaker: Dr.A.K.Choudhury, VECC, Kolkata
Category: Seminar of General Interest
Venue: Lecture Hall
STAR and PHENIX measurements of elliptic flow, in Au+Au collisions at RHIC,revealed an interesting scaling property: elliptic flow, of different particle species at differentcollisions centrality, when scaled by the initial eccentricity and constituent quark numbers ($n_q$)is a singlefunction of $KE_T/n_q$, $KE_T=m_T-m$. Initial eccentricity scaling suggests that elliptic flow is driven by the initial spatial asymmetry. Constituentquark number scaling indicate existence of initial collective partonic state. Elliptic flow is best explained in ahydrodynamic model. In non-zero impact parameter collisions, the reaction zone is spatially asymmetric.Differential pressure gradient convert the spatial asymmetry to momentum asymmetry, resulting in elliptic flow. Inthe Israel-Stewart's theory of 2nd order dissipative hydrodynamics, we study the universal scaling of ellipticflow in ideal and viscous fluid evolution. Initial eccentricity scaling is only approximate in ideal hydrodynamicsand gets better with viscosity. Ideal or viscous hydrodynamic do not indicate constituent quarks number scaling anduniversal scaling is only approximate,violated by $sim\% or more in ideal or viscous fluid evolution. We also showthat RHIC data on elliptic flowdemand very small QGP viscosity, $eta/s ~0.08$, indicating nearly ideal fluid isproduced in Au+Au collisions
17-09-2009 At 04:30:00 PM
Speaker: Prof. T. Venkatesan, NanoCore and ECE and Physics Departments, National University of Singapore
Category: Seminar of General Interest
Venue: Lecture Hall
In my talk I will describe some of the cutting edge experiments that aregoing on in my research group. Our focus is the growth of thin films withatomic level control for both basic science and applications.I will focuson the area of Oxide Electronics where we are focused on a number ofimportant problems.The first will be the observation of ferromagnetism in oxides with nomagnetic dopants such as Nb or Ta doped TiO2. In both these cases,magnetic signatures were first seen by the observation of strong Kondoscattering observed in the low temperature resistivities. We confirm thatthe observed resistivity anomalies arise with a strong Kondo contributionwith a small weak localization contribution.. With further optimizationroom temperature ferromagnetism is seen in these materials. I will discussthe various experimental supporting factors besides just SQUID measurementthat give evidence for this ferromagnetism and how we rule out the effectsof artifacts, a common problem with SQUID only measurements. I will touchupon our recent efforts in the formation of Super Hydrogenic Systems, anew class of materials and give one specific example, that of Ce dopedLu2O3. Lastly but not the least I will cover some of our recentexperiments on integrating oxides with futuristic materials such asgraphene.
01-10-2009 At 04:00:00 PM
Speaker: Dr. P.Arumugam, Department of Physics, IIT, Roorkee
Category: TPSC Seminar
Venue: Lecture Hall
Studies at the extreme limits of the nuclear chart have gainedmomentum in the last decade with the advent of new experimentalfacilities. The production of new exotic nuclei lead to the discoveryof several exciting new phenomena like for example, neutron skins andhalos in neutron-rich nuclei, and the novel decay mechanism of protonradioactivity in proton rich nuclei around the proton drip line. Ontheoretical grounds, the description of these new phenomena, apartfrom validating existing models in regions far from stability,requires the formulation of new theories. Recent developments in thisarea will be discussed
12-10-2009 At 04:00:00 PM
Speaker: Prof. Sudipta Mukherji , IOP
Category: Colloquium
Venue: Lecture Hall
22-10-2009 At 12:00:11 AM
Speaker: Dr. S.K.Bandyopadhyay, VECC, Kolkata
Category: Seminar of General Interest
Venue: Lecture Hall
Irradiation and Implantation studies are being regularly carried out at VECC with the room temperature cyclotron. Activities in Materials Science are having two dimensionalities-1) Studies on Nuclear Structural Materials with a view to assessing the damage in the context of applications to Nuclear reactors and 2) Studies on various novel materials like High Temperature and low temperature superconductors, novel oxides, polymers etc. with the purpose of extracting tailor made properties and understanding the basic mechanism in the process. The second aspect will be talked about. Recently, Superconducting Cyclotron with high energy heavy ions and 6.4GHz ECR ion source are being activated for the purpose of different experiments. The ongoing experiments using ECR source and the future plans will be highlighted.
26-10-2009 At 04:00:00 PM
Speaker: Prof. A.M.Srivastava, IOP, BBSR
Category: Colloquium
Venue: Lecture Hall
06-11-2009 At 11:00:00 AM
Speaker: Prof. R. Rangarajan, PRL, Ahmedabad
Category: HEP Seminar of General Interest
Venue: Lecture Hall
The early universe went through a phase of accelerated expansion called inflation. After inflation the field driving inflation, the inflaton, decays and its decay products thermalise and the universe reheats. The thermal universe now contains all the known particles and dark matter particles. Gravitinos are supersymmetric particles that also are produced and their presence has very adverse cosmological consequences. Mechanisms to suppress gravitino production make it difficult to produce the observed matter-antimatter asymmetry of the universe. We discuss aspects of how this issue can be resolved involving a detailed understanding of how the universe reheats after inflation.
09-11-2009 At 04:00:00 PM
Speaker: Prof. Somen Bhattacharjee, IOP
Category: Colloquium
Venue: Lecture Hall
11-11-2009 At 04:00:00 PM
Speaker: Dr. Subhashish Banerjee, CMI, Chennai
Category: TPSC Seminar
Venue: Lecture Hall
We will discuss the entanglement in a two-qubit systemdynamically generated by the interaction of the qubit system with itsenvironment (bath or reservoir). The interactions considered would beboth of the purely dephasing, no energy exchange, as well as dissipative, dephasing accompanied with dissipation.An introduction is provided tothe concept of entanglement as well as Open Quantum Systems. Sinceinteraction with the environment makes the system mixed, we discuss indetail the measure of entanglement called concurrence as well as arecently introduced description of mixed state entanglement usingprobability density function.
23-11-2009 At 04:00:00 PM
Speaker: Prof. D.P. Mahapatra, IOP, Bhubaneswar
Category: Colloquium
Venue: Lecture Hall
24-11-2009 At 04:00:00 PM
Speaker: Dr. Sreedhar B. Dutta (KIAS, Seoul/Univ. of Nancy, France)
Category: Condensed Matter Theory Seminar
Venue: Lecture Hall
Ageing phenomenon is observed in slowly relaxing nonequilibrium systems.Examples not only include complex glassy systems, but also simplestatistical mechanics systems when rapidly quenched in temperature.These quenched systems usually show scaling properties and universalbehaviour while ageing. I shall give an elementary introduction anddiscuss what an ageing state is, how we try to describe and monitor it,and to what extent it can carry a memory.
07-12-2009 At 04:00:00 PM
Speaker: Prof. Mukunda P Das,Department of Theoretical Physics, The Australian National University, Australia
Category: Colloquium
Venue: Lecture Hall
Before 1986 it was generally believed that ceramic oxides are poorconductors for electrical conduction. Against this perception asurprise appeared in late 1986 by Bednorz and Müller, who showed thata doped ceramic cuprate becomes a high temperature superconductor. Nowwe find several dozens of high Tc superconductors and they are allceramic perovskites. Although a large volume of literature exists onvarious aspect of high Tc materials, yet we are far from understandingthe real mystery- how these ceramic materials superconduct? In thistalk I present an appraisal of variety of observed anomalies anddiscuss what do these anomalies indicate towards the microscopicmechanism of superconducting pairing?
21-12-2009 At 04:00:00 PM
Speaker: Dr. A.K.Pati, IOP
Category: Colloquium
Venue: Lecture Hall
Quantum information theory has emerged as one of the frontier areas of research that not only aims to offer radically new ways of processing information but also offers new inights into the nature of quantum world. However, if we ask what is quantum information, then the very notion of quantum information is not yet defined in a more fundamental way. It may be possible that we gain better and better understanding of quantum information by asking questions like what is so `quantum' about quantum information and investigating essential differences between classical and quantum information. In this talk I will focus on these aspects and highlight some fundamental differences between them.
22-12-2009 At 12:00:11 AM
Speaker: Prof. R.K. Soni, IIT, New Delhi
Category: Biresh Patel Memorial Lecture
Venue: Lecture Hall
The metal nanoparticles are interesting from the point of view of their optical properties, which strongly depend on both the particle size and shape. Surface plasmon resonances in metallic nanoparticles are used for a variety of applications due to the large enhancement and localization of the electromagnetic field at the metal/dielectric interface. The plasmonic coupling of metal nanoparticles with light enhances a broad range of useful optical phenomena, such as resonant light scattering, surface plasmon resonance absorption, metal induced fluorescence enhancement and surface-enhanced Raman scattering, all of which have tremendous potential for ultrasensitive chemical and biomolecular detection and analysis. Further functionalization of metal nanoparticles can be achieved by either laser exposure or surfactant. Moreover, the surfactant increases the stability of the nanoparticles and avoids the agglomeration and sedimentation. Surface functionalization of MNPs can be monitored in real time by UV-visible spectroscopy of the plasmon resonance. The optical and catalytic properties of Ag and Au nanoparticles are useful to a diverse range of applications. By combining these two metals into a single entity or forming core-shell structures, both the stability and catalytic properties can be further enhanced and localized surface plasmon absorption can be varied. In this talk, we present recent progress in laser ablation of noble metal target in a confining liquid for the synthesis of nanocrystals and formation of nanocomposites. In the recent years laser ablation synthesis in solution has emerged as a reliable alternative to traditional chemical reduction methods for synthesis of noble metal nanoparticles (MNP). The size manipulation by laser irradiation and functionalization of MNPs will be discussed. While femtosecond laser pulses can induce a shape transformation, such as a rod-to-sphere transition, nanosecond laser pulses can cause fragmentation into smaller particles. High fluences can be powerful enough to raise the temperature of the metal above its melting point, and thereby it can be used as a convenient tool to control the shape and size distribution of nanoparticles and intermediate phase nano-soldered composites. Also, the biofunctionality of laser-ablated gold nanoparticles can be tailored through the bonding between gold and amino-group. This linkage of amino-group to gold give rise to red shift in plasmon absorption band and related to the degree oxidation of gold. Nanoaggregate structures formed by gold nanospheres of different sizes and generated by laser ablation from solid gold into water will be discussed for their potential as enhancing nanostructures in surface enhanced Raman scattering (SERS).