| # | Title | Speaker | Venue | Date | Abstract |
|---|---|---|---|---|---|
| 1 | Evolution of Texture in Materials | Dr. Ajit Panigrahi CSIR - Institute of Minerals and materials Technology (IMMT), Bhubaneswar |
CSIR-IMMT meeting hall | 2019-Aug-28 03:30 PM | |
| 2 | Bose, Bosons and Boson condensation | Professor Mukunda P Das Department of Theoretical Physics, RSPE, The Australian National University, Canberra, Australia |
IoP lecture Hall | 2018-Dec-14 04:00 AM | |
| 3 | Kondo Effect in Condensed Matter | Professor Mukunda P Das Department of Theoretical Physics, RSPE, The Australian National University, Canberra, Australia |
IoP lecture Hall | 2018-Dec-17 04:00 PM | |
| 4 | Anomaly in Quantized Conductance in Quasi-1D Metallic Quantum Wire beyond the Landauer model | Prof. Mukunda Das Department of Theoretical Physics, RSPE, The Australian National University, Canberra, Australia |
IoP lecture Hall | 2018-Dec-12 04:00 PM | |
| 5 | Heterogeneous Electrocatalysts for Solid-state Alkaline Water Electrolyzers | Prof. Vijay K. Ramani Washington University in St. Louis and IIT-Delhi VAJRA Fellow |
CSIR-IMMT meeting Hall | 2018-Aug-21 04:00 PM | |
| 6 | Clean water using advanced materials: Science, technology, incubation and industry | Prof. T. Pradeep Department of Chemistry, Indian Institute of Technology Madras, Chennai |
CSIR-IMMT meeting Hall | 2018-Jun-27 04:00 PM | |
| 7 | Challenges in surgery for conjoined head | Prof. Ashok Mahapatra Ex-Director AIIMS Bhubaneswar |
CSIR-IMMT meeting Hall | 2018-May-11 03:30 PM | |
| 8 | Superconductivity in Nano Systems | Prof. M. P.Das Department of Theoretical Physics, The Australian National University |
IoP Lecture Hall | 2017-Dec-11 10:00 AM | |
| 9 | Conductance ANOMALIES in quasi-iD systems | Prof. M. P.Das Department of Theoretical Physics, The Australian National University |
IoP Lecture Hall | 2017-Dec-07 10:00 AM | |
| 10 | General theory of transport, Lecture (1) | Prof. M. P.Das Department of Theoretical Physics, The Australian National University |
IoP Lecture Hall | 2017-Dec-05 10:00 AM |
Title: Evolution of Texture in Materials
Speaker: Dr. Ajit Panigrahi, CSIR - Institute of Minerals and materials Technology (IMMT), Bhubaneswar
Venue: CSIR-IMMT meeting hall
Date: 2019-Aug-28 15:30:00
Abstract: Texture in materials science is defined as the way in which a poly-crystalline material is woven. Due to texture the material becomes anisotropic. The effect of texture on properties of materials should be exploited to produce materials with specific behaviour or characteristics.
Title: Bose, Bosons and Boson condensation
Speaker: Professor Mukunda P Das, Department of Theoretical Physics, RSPE, The Australian National University, Canberra, Australia
Venue: IoP lecture Hall
Date: 2018-Dec-14 04:00:00
Abstract:
Title: Kondo Effect in Condensed Matter
Speaker: Professor Mukunda P Das, Department of Theoretical Physics, RSPE, The Australian National University, Canberra, Australia
Venue: IoP lecture Hall
Date: 2018-Dec-17 16:00:00
Abstract: It was surprising that a single impurity spin coupled to a Fermi gas in a metal, produces resistance minimum at low temperatures. It took 30 years from the first observation in Leiden and Jun Kondo gave a plausible explanation, known after his name. Since then the Kondo problem has played a massive role in many body physics over the years, both for the methods required to solve it, and because it kept popping up in different guises. In the context of explaining certain anomaly in the conductance of quasi-one dimensional metals (ref. to my first talk), Kondo effect is an attractive candidate in recent years. Besides the application to mesoscopic physics, I shall highlight novel features like Kondo insulators, charge and spin Kondo effect and topological Kondo effect.
Title: Anomaly in Quantized Conductance in Quasi-1D Metallic Quantum Wire beyond the Landauer model
Speaker: Prof. Mukunda Das, Department of Theoretical Physics, RSPE, The Australian National University, Canberra, Australia
Venue: IoP lecture Hall
Date: 2018-Dec-12 16:00:00
Abstract: We study the quantized conductance of quasi-1D metallic quantum wire, where it has been observed to have a striking departure from the canonical quantized step sequence. As per general understanding each independent sub-band structure provides a Landauer conductance quantum based on coherent single carrier transmission. The observed enhanced conductance depends on applied source-drain bias and is beyond the Landauer limit, seems as a second anomaly. The first one is studied extensively known as 0.7 conductance anomaly (see our earlier work in Adv. Nat. Sci.: Nanosci. Nanotechnol. 8 023001 (2017). In order to understand the second anomaly we employ quantum kinetic approach by including inter-sub-band contribution (J. Phys.: Condens Matter 30 385304 (2018)). We argue that the elevated conductance plateau is inherently nonlinear. It is extremely flat and exceeds Landauer’s upper bound violating the unitarity limit of linear response theory.
Title: Heterogeneous Electrocatalysts for Solid-state Alkaline Water Electrolyzers
Speaker: Prof. Vijay K. Ramani, Washington University in St. Louis and IIT-Delhi VAJRA Fellow
Venue: CSIR-IMMT meeting Hall
Date: 2018-Aug-21 16:00:00
Abstract: Hydrogen production by alkaline water electrolysis using hydroxide-conducting anion exchange membranes (AEMs) has seen a renewed interest as an alternative to traditional liquid alkaline water electrolyzers, proton exchange membrane (PEM) electrolyzers, and solid oxide water electrolyzers. Anion exchange membrane electrolyzers provide an efficient, modular, and reliable method to produce hydrogen from water and renewable electricity sources. One of the main benefits of anion exchange membrane electrolyzers arises from the more facile oxygen evolution reaction (OER) kinetics in alkaline environments and the concomitant possibility of employing non-platinum group (non-PGM) catalysts without suffering the stability problems common in acid media. However, a challenge that arises is the sluggish kinetics for the hydrogen evolution reaction (HER) in alkaline media. During our research into active and stable OER catalysts for alkaline operation, electrically conducting metal oxides (eliminating the need of a conducting support for the catalyst) with the pyrochlore structure (A2B2O7-y, with A=Pb or Bi and B= Ru, Ir or Os) emerged as among the most active and stable OER catalysts. Specifically, the exceptional OER activity and stability of lead ruthenate pyrochlore catalysts was quantified using a rotating disk electrode and further evaluated in an anion exchange membrane water electrolyzer. The OER overpotentials obtained with the pyrochlore catalyst in the full cell were 0.1-0.2 V lower than for IrO2 across the entire current density range, with stable performance over hundreds of hours. Since operation in alkaline media leads to more sluggish HER kinetics, we have evaluated ways to improve the HER activity of Pt-based electrocatalysts at high pH. Bifunctional electrocatalysts containing Pt clusters to combine the protons to form hydrogen gas, and hydrophilic domains able accelerate water dissociation were able to substantially improve HER kinetics under alkaline conditions. The hydrophilic moieties that help the water splitting are varied. We have investigated nickel hydroxide and ruthenium oxide as co-catalysts together with Pt. The bi-functional catalysts were evaluated in an anion-exchange membrane water electrolyzer operated with ultrapure water, and outperformed Pt/C by about 0.15 V across the entire current density range. Similarly, electrolyzer experiments showed that Pt/C/10%Ni(OH)2 performs as well as Pt/C with only half the Pt loading. We have also demonstrated enhanced HER activity in a Pt electrocatalyst deposited onto a mixed-metal-oxide support composed of titanium dioxide (TiO2) and ruthenium dioxide (RuO2). This presentation will elaborate on both the OER and HER electrocatalysis in alkaline media, and will provide specific examples of successfully translated electrocatalysts. A brief overview of other ongoing projects will also be presented.
Title: Clean water using advanced materials: Science, technology, incubation and industry
Speaker: Prof. T. Pradeep, Department of Chemistry, Indian Institute of Technology Madras, Chennai
Venue: CSIR-IMMT meeting Hall
Date: 2018-Jun-27 16:00:00
Abstract: Access to clean water is one of the most important indicators of development. This water has to be affordable to make a meaningful impact to the society. Diverse variety of materials are important in accomplishing this objective. We have been studying the chemistry of nanomaterials from the context of delivering microbially and chemically safe drinking water. Creation of affordable materials for constant release of silver ions is one of the most promising ways to make water microbially safe. Combining the capacity of diverse nanocomposites to scavenge toxic species such as arsenic, lead, and other contaminants along with the above capability can result in affordable, all-inclusive drinking water purifiers that can function without electricity. The critical problem in achieving this is the synthesis of stable materials that can release or adsorb ions continuously in the presence of complex species usually present in drinking water that deposit and cause scaling on nanomaterial surfaces. We have shown that such constant release/adsorbing materials can be synthesized in a simple and effective fashion in water itself without the use of electrical power. The nanocomposite exhibits river sand-like properties, such as higher shear strength in loose and wet forms. These materials have been used to develop an affordable water purifier to deliver clean drinking water at Rs. 130/y per family. The ability to prepare nanostructured compositions at near ambient temperature has wide relevance for adsorption-based water purification. We have implemented such solutions already in arsenic affected areas of India. In the next 12 months, we are expected to provide arsenic free water to 1000,000 people. We have implemented other technologies which involve electrodeioniosation. Translation of ours results led to the incubation of multiple companies and two of them have their own manufacturing units now. A healthy mixture of basic science, applications and business in the Indian context is manifested here. Several new technologies are in the pipeline, a sample of these will be presented.
Title: Challenges in surgery for conjoined head
Speaker: Prof. Ashok Mahapatra, Ex-Director AIIMS Bhubaneswar
Venue: CSIR-IMMT meeting Hall
Date: 2018-May-11 15:30:00
Abstract: Challenges in surgery for conjoined head
Title: Superconductivity in Nano Systems
Speaker: Prof. M. P.Das, Department of Theoretical Physics, The Australian National University
Venue: IoP Lecture Hall
Date: 2017-Dec-11 10:00:00
Abstract:
Title: Conductance ANOMALIES in quasi-iD systems
Speaker: Prof. M. P.Das, Department of Theoretical Physics, The Australian National University
Venue: IoP Lecture Hall
Date: 2017-Dec-07 10:00:00
Abstract:
Title: General theory of transport, Lecture (1)
Speaker: Prof. M. P.Das, Department of Theoretical Physics, The Australian National University
Venue: IoP Lecture Hall
Date: 2017-Dec-05 10:00:00
Abstract:
Title: Photoelectric Effect: Truth vs. Hype
Speaker: Prof. M. P.Das, Department of Theoretical Physics, The Australian National University
Venue: IoP Lecture Hall
Date: 2017-Dec-01 16:00:00
Abstract: Einstein had an enigmatic ability to arrive at powerful conclusions using a few well-known assumptions. Explanation of the Photoelectric effect is a bright example of that. In this talk we retrospect the so-called quantum revolution beginning with the photoelectric phenomenon. Following this historical endeavor, we present post-Einstein development of theories and experiments on photoemission from solids.
Title: Amorphous Materials with Magnetic Degrees of Freedom
Speaker: Dr. Bhaskar Sen Gupta, Max Planck Institute for Polymer Research Mainz , Germany
Venue: IOP Lecture Hall
Date: 2017-May-02 16:00:00
Abstract: Amorphous magnetic materials, like metallic glasses exhibit fascinating cross-effects between mechanical and magnetic responses. Magnetostriction and Barkhausen Noise are just a few of these effects. In this talk I will describe new microscopic models of amorphous magnets where all the magnetic randomness come from the glassy nature of the material. The model employed offers new perspectives on many important effects and richer physics. I will also present a theory to explain some of the interesting effects that are typical to such systems.
Title: First principles investigation on Quantum Materials
Speaker: Dr. Subhasish Mandal, Yale University, USA
Venue: IOP Lecture Hall
Date: 2017-Apr-03 16:00:00
Abstract: Computer simulations based on first principles calculations play a central role in helping us understand, predict, and engineer physical, chemical, and electronic properties of technologically relevant materials. This can solve many problems towards building faster, smaller and cheaper devices for processing and storing information as well as for saving energy. Many of these processes involve electron excitations and strong local magnetic fluctuation that the ‘standard model’ of electronic structure, Density Functional Theory (DFT), can’t capture properly. In this context, I will highlight two popular approaches that go beyond the standard DFT. First, I will discuss how Dynamical Mean Field Theory (DMFT) in combination with DFT has recently been successful for detailed modeling of the electronic structure of many complex materials with strong electron correlation. To give an example, I will show the iron-based superconductors on both bulk and monolayer phases and their anomalous properties, which have their origin in strong Hund's coupling and give rise to the rich physics of Hund's metals. Next, I will discuss my collaborative effort toward developing a high scalable, open-source GW software to compute electronic excited states more efficiently for petascale architectures using the Charm++ parallel framework. At the end, I will briefly discuss topological crystalline insulators, which are a new class of topological materials where electronic surface states are topologically protected along certain crystallographic directions by crystal symmetry. I will show that, without any external perturbation, both massless Dirac fermions protected by the crystal symmetry and massive Dirac fermions with crystal symmetry breaking can coexist on a single surface
Title: Supersymmetry on a Spacetime Lattice
Speaker: Anosh Joseph, ICTS
Venue: IoP Lecture Hall
Date: 2017-Mar-07 16:00:00
Abstract: The AdS/CFT correspondence or gauge theory-gravity correspondence is one of the most beautiful results that string theory has produced. This correspondence relates theories with gravity and theories without gravity through interesting dualities. In this talk I will describe how such dualities can be tested using Monte Carlo simulations of strongly coupled gauge theories known as supersymmetric Yang-Mills theories. Supersymmetric gauge theories can be simulated on a computer by discretizing them on a Euclidean spacetime lattice and using suitable lattice QCD algorithms. I will review the current status of the Monte Carlo simulations of supersymmetric gauge theories, which includes interesting insights into black holes and quantum gravity.
Title: Lecture-2 Floquet Time Crystals – Periodically driven systems
Speaker: Prof. S. D. Mahanti, Michigan State University & Adjunct Professor, IOP
Venue: IOP Lecture Hall
Date: 2017-Mar-10 11:00:00
Abstract: In recent years there have been a flurry of activity surrounding the ideas of time crystals where there is a spontaneous breaking of time translational symmetry. This has lead to the study of periodically driven quantum systems and the physics of Floquet-Bloch bands. In the latter context one can not only change the nature of topologically protected states but one can induce topological phase transitions by light. In these two lectures I will discuss what I have learnt about these ideas, reviewing some important papers and some experimental realizations.
Title: Different Facets of PT Symmetry
Speaker: Prof. A.Khare, Ex-Professor, IOP,
Venue: IOP Lecture Hall
Date: 2017-Mar-03 16:00:00
Abstract: In this talk I will discuss many interesting developments which have happened mainly in classical mechanics, Integrable models and classical field theory due to PT-symmetry. For example, I will discuss new reflectionless PT-symmetric potentials and hence complex PT-invariant solution of KdV equation. I also discuss new PT-invariant complex periodic solutions of KdV equation and conjecture that these potentials must have novel band structure. I then show that any model which admits kink solution, will always also admit PT-invariant complex kink solution and that it is also topologically stable. I further discuss stability of solitons of Nonlinear Schrodinger equation with PT-invariant complex potentials. I discuss a coupled oscillator model with balanced growth and loss and show that (unlike the single oscillator with friction) it is an Hamiltonian system. Finally I discuss PT-invariant Gross-Neuve model with N =1 (Soler model).
Title: Periodically driven topological systems: Where we are now
Speaker: Prof. Arijit Kundu, IIT Kanpur, India
Venue: IOP Lecture Hall
Date: 2017-Mar-16 16:00:00
Abstract: Periodically driven systems, often called Floquet systems has been of center of interest for last few years. With the tremendous activity in the field we have made significant advancement in understanding such systems as well as in experimentally realizing them. My talk will try to give an overview of our current understanding and I'll try to point out some unresolved problems.
Title: Lecture1: Classical and Quantum Time Crystals – Spontaneous breaking of time translation symmetry
Speaker: Prof. S. D. Mahanti, Michigan State University and Adjunct Professor, IOP
Venue: IOP Lecture Hall
Date: 2017-Mar-06 16:00:00
Abstract: In recent years there have been a flurry of activity surrounding the ideas of time crystals where there is a spontaneous breaking of time translational symmetry. This has lead to the study of periodically driven quantum systems and the physics of Floquet-Bloch bands. In the latter context one can not only change the nature of topologically protected states but one can induce topological phase transitions by light. In these two lectures I will discuss what I have learnt about these ideas, reviewing some important papers and some experimental realizations.
Title: Non-local multi-particle geometric phases in electronic intensity interferometry
Speaker: Prof. Sourin Das, IISER Kolkata, India
Venue: IOP Lecture Hall
Date: 2017-Mar-02 16:00:00
Abstract: Berry's discovery of the geometric phase in 1984 led to a deeper understanding of wide range of phenomena in different areas of physics starting from molecular physics to condensed matter systems. In this talk, I will first provide an introduction to the concept of geometric phase in spirit of Berry's definition and then relate it to its generalized version as anticipated in earlier works of Pancharatnam. I shall then apply Pancharatnam's ideas to obtain non-local and multi-particle geometric phase in the context of electronic version of the Hanbury-Brown and Twiss intensity interferometer. I will discuss a possible experimental realization of this effect by exploiting edge states of two-dimensional topological insulators (2d TI). It will be shown that the electrical transport in quantum spin Hall (an example of the 2d TI state) edge can host a two particle Aharonov - Bohm (AB) effect in spin space which essentially is an example of multi-particle and non-local geometric phase. This two particle “spin A-B effect†stems from an effective AB flux piercing a two particle loop identified on the Bloch sphere which can be attributed to an abstract monopole of strength 1/2 placed at the origin of the sphere.
Title: Quantum-dot heat engines, quantum clocks and a Landauer principle for time-keeping
Speaker: Prof. Bhaskaran Muralidharan, IIT Bombay, India
Venue: IOP Lecture Hall
Date: 2017-Feb-23 16:00:00
Abstract: In this talk, we present recent works [1-2] on two distinct aspects related to quantum dots. In the first part, thermoelectric response of a dissipative quantum dot heat engine based on the Anderson-Holstein model is analyzed. We delve into two relevant operating limits, (i) when the dot phonon modes are out of equilibrium, and (ii) when the dot phonon modes are strongly coupled to a thermal environment. We discuss several nuances related to the heat engine operation under both limits. When relaxation via a heat bath is involved, we estimate the dot temperature by incorporating a thermometer bath, and it is shown that the dot temperature deviates from the bath temperature as electron-phonon interaction in the dot becomes stronger. Consequently, it is demonstrated that the dot temperature controls the direction of phonon heat currents, thereby influencing the thermoelectric performance. In the second part, we bring in a Bayesian viewpoint to the analysis of clocks, specifically taking the Salecker Wigner clock formulation [3] and explore a novel set up to estimate the tunneling time [2] between electrons in a contact and a quantum dot weakly coupled to it. Using the exponential tunneling distribution as a priors for clocks, we analyze the case of a single precessing spin in a quantum dot. We find that, at least with a single qubit, quantum mechanics does not allow exact timekeeping. We find the optimal ratio of angular velocity of precession to rate of the exponential distribution that leads to maximum accuracy. Further, we find an energy versus accuracy tradeoff in a form reminiscent of the Szilard-Landauer principle --- the energy cost is at least k_BT times the improvement in accuracy as measured by the entropy reduction in going from the prior distribution to the posterior distribution. References: [1] B. De and B. Muralidharan, Phys Rev B, 94, 165416, (2016). [2] M Gopalkrishnan, V. Kandula, P. Sriram, A. Deshpande and B. Muralidharan, ArXiv: 1602.00508, Proceedings of IEEE Symposium on Information Theory, (2016). [3] A. Peres, Am. J. Phys., 48, 552, (1980).
Title: Radiations, their detection and Detectors (Lecture-4)
Speaker: Prof. D. P. Mahapatra, Ex-Professor, IOP
Venue: IOP Lecture Hall
Date: 2017-Mar-01 15:30:00
Abstract:
Title: Radiations, their detection and Detectors (Lecture-3)
Speaker: Prof. D. P. Mahapatra, Ex-Professor, IOP
Venue: IOP Lecture Hall
Date: 2017-Feb-28 15:30:00
Abstract:
Title: Radiations, their detection and Detectors (Lecture-2)
Speaker: Prof. D. P. Mahapatra, Ex-Professor of IOP
Venue: IOP Lecture Hall
Date: 2017-Feb-22 15:30:00
Abstract:
Title: Radiations, their detection and Detectors (Lecture-1)
Speaker: Prof. D. P. Mahapatra, Ex-Professor, IOP
Venue: IOP Lecture Hall
Date: 2017-Feb-21 15:30:00
Abstract:
Title: Turbulence–still unsolved problem of classical Physics
Speaker: Prof. P. Satyamurthy, Institute for Plasma Research,Gandhinagar
Venue: Dept of Physics (LH-II), Utkal University
Date: 2017-Feb-17 15:00:00
Abstract: This talk presents an overall review of turbulence, one of the oldest problemsof classical physics. The presentation includes explaining; what is turbulence, why we should study them, what are the governing equations. The complexity of the equations, issues related to analytical, numerical solutions are presented. Various empirical models used for engineering applications and their inherent limitations are discussed. The current understanding of turbulence evolved starting from Leonardo Davinciin 15th century to Kolmogorov’s theory proposed in 1941 is discussed. The talk ends with reviewing current status and likely future scenario.
Title: ERE, the all pervading Red Space Glow: What do we know about it ?
Speaker: Prof. D P Mahapatra, Ex-Professor of IOP
Venue: IOP Lecture Hall
Date: 2017-Feb-16 16:00:00
Abstract: ERE (Extended Red Emission), corresponds to a wide band red glow present throughout the Milky way and other Galaxies. Over the last 40 years, there has been a lot of debate on the type of emitters that are responsible for this. Several models involving different emitters such as, a-CH, n-Si, charged as well as neutral PAH (poly aromatic hydrocarbon) species, n-diamond etc have been proposed to explain ERE. The size and the size distribution of the emitters also determine the characteristics of the emission band. Some of these issues and the physics involved will be presented.
Title: Ph.D. Thesis: Au-Ag Bimetallic Nanostructures Growth and Characterization On Ultra Clean Silicon Substrates
Speaker: Mr. Anjan Bhukta, Institute of Physics, Bhubaneswar (Presently Visiting Postdoctoral Fellow, Indian Institute of Technology Bhubaneswar, Bhubaneswar)
Venue: Main Lecture Hall
Date: 2017-Feb-09 16:00:00
Abstract: Ph.D. Thesis - Viva-Voce
Title: Faceted particles formed by the frustrated packing of anisotropic colloids on curved surfaces
Speaker: Dr. Abhijit Ghosh, Brandeis University, Massachusetts, USA
Venue: IOP Lecture Hall
Date: 2017-Feb-13 16:00:00
Abstract: We use computer simulations and simple theoretical models to analyze the morphologies that result when rod-like particles end-attach onto a curved surface, creating a finite thickness monolayer aligned with the surface normal. This geometry leads to two forms of frustration, one associated with the incompatibility of hexagonal order on surfaces with Gaussian curvature, and the second reflecting the deformation of a layer with finite thickness on a surface with non-zero mean curvature. We show that the latter effect leads to a faceting mechanism. Above threshold values of inter-particle attraction strength and surface mean curvature, the adsorbed layer undergoes a transition from orientational disorder to an ordered state that is demarcated by reproducible patterns of line defects. The number of facets is controlled by the competition between line defect energy and intra-facet strain. Tuning control parameters thus leads to a rich variety of morphologies, including icosahedral particles and irregular polyhedra. In addition to suggesting a new strategy for the synthesis of aspherical particles with tunable symmetries, our results may shed light on recent experiments in which rod-like HIV GAG proteins assemble around nanoscale particles. Reference : Faceted particles formed by the frustrated packing of anisotropic colloids on curved surfaces Naiyin Yu,†Abhijit Ghosh†and Michael F. Hagan* Soft Matter, 12, 8990 – 8998, (2016) (Selected as internal cover article)
Title: Nobel Prize in Physics-2016
Speaker: Prof. Somendra M Bhattacharjee, Dr. Debakanta Samal, Prof. Karmadeva Maharana,
Venue: Lecture Hall II- Dept. of Physics, Utkal University
Date: 2017-Feb-06 14:45:00
Abstract:
Title: Understanding Charge Transport in Lead-Halide Perovskite
Speaker: Dr. Satyaprasad P Senanayak, Cavendish Laboratory, University of Cambridge, UK
Venue: IOP Lecture Hall
Date: 2017-Jan-23 16:00:00
Abstract: Lead halide perovskite materials have caught lot of attention because of its usage in developing novel photovoltaics with effeciencies exceeding 22%. This level of optoelectronic performance has been possible due to clean band-gap, low disorder and various interesting properties. Despite the development of high efficiency optoelectronic devices, clear understanding of the charge transport and scattering mechanism has not yet been understood. Field effect transistors are an effective way to understand the charge transport mechanism. In the talk, I will describe the development of first room temperature operating field effect transistor with lead iodide perovskite through a combination of material and device engineering. Fundamental understanding of the various scattering mechanisms involved in the charge transport physics is then development through a combination of electrical and spectroscopic investigation [1]. The next part of the talk is on understanding the charge transport of polymer semiconductors. With suitable chemical design, interface and device engineering it was possible to approach disorder free transport in these inherently amorphous materials. Furthermore, a range of strategies would be discussed which allow flexible polymer logic circuits with with switching speed of 10 MHz, operating at 1 V and have a power consumption as low as 10 nW. These characteristics make the flexible polymer devices to have performance comparable or better than a-Si devices[2-3]. References: 1. Satyaprasad P Senanayak, Richard Friend, Henning Sirringhaus et.al.; Science, AAAS (Accepted). 2. Satyaprasad P Senanayak and Narayan K.S; Adv. Funct. Materials, 24, 22, 3331,2015. 3. Satyaprasad P Senanayak and Narayan K.S; Phys. Rev. B, B 91, 115302, 2016.
Title: Search methods that have made the discovery of gravitational waves possible
Speaker: Dr. Satya Mohapatra, Kavli Institute for Astrophysics and Space Research, MIT
Venue: Ground Floor, School of Basic Sciences, IIT Bhubaneswar
Date: 2017-Jan-20 16:00:00
Abstract: Last year announcement of the detection of gravitational waves have opened a new window to look at the universe. I will talk about the search algorithm and methods that made those detection possible. I will also briefly talk about the implications of these discoveries
Title: Non-trivial topology : Atomic-scale skyrmion in chiral magnets
Speaker: Dr. Ashis Kumar Nandy, Uppsala University, Sweden
Venue: IOP Lecture Hall
Date: 2017-Jan-18 16:00:00
Abstract: Skyrmions which are localized magnetic vortices with particle-like properties may occur as stable or metastable states in chiral magnets. The unique static and dynamic properties of magnetic skyrmions driven by their nontrivial topology offer attractive perspectives for future spintronic applications and interesting objects for fundamental research. Of particular interests is atomic-scale skyrmions either appear isolated or in the form of a lattice, whose stability is expected to be robust over a large range of magnetic fields and temperatures. This brings into play ultrathin layers of chiral magnets with nonmicromagnetically describable magnetic behavior due to the competing ferro- and antiferromagnetically coupled exchange interactions between different atomic sites that are finally the origin of stable exchange spin spirals of atomic length scale. In this case, the spin-orbit coupling in the presence of broken inversion symmetry ensures strong Dzyaloshinskii-Moriya interaction which select a particular chirality of the spirals. Based on density functional theory and atomistic spin dynamics simulations, we have extended the micromagnetic concept of stabilizing skyrmions by applied magnetic fields to skyrmions stabilized by interlayer exchange coupling. This enables engineering zero field skyrmion phases in chiral magnets and provides a perspective direction to extend the number of possible systems where magnetic skyrmions can be observed also at elevated temperatures. It is again necessary to understand the dynamic properties of skyrmions within the general framework of fundamental physics before it can be exploited in devices. We further present how the topological charge of an isolated skyrmion can be used as an information bit in a data storage devices. The individual skyrmion can be nucleated in a finite domain by a single magnetic pulse and then another pulse is used for controlled switching between two isolated states with opposite polarity and topological charge. This occurs through a complex energy landscape with various local minima of transient topological states: a chiral-achiral meron pair, an achiral skyrmion and a half-switched skyrmion.
Title: Spintronics with 2D materials heterostructures
Speaker: Prof. Saroj Prasad Dash, Chalmers University of Technology, Gothenburg, Sweden
Venue: IOP Lecture Hall
Date: 2017-Jan-24 16:00:00
Abstract: Exploiting the spin degrees of freedom of electrons in solid state devices is considered as one of the alternative state variables for information storage and processing beyond the charge based technology. We have shown that the main stream semiconductor, silicon, has great potential with creation and detection of spin polarization up to room temperature [1,2,3]. However, one of the primary challenges in this field is the transport and manipulation of spin polarization. In this regard, two-dimensional (2D) atomic crystals provide a large class of materials proposed to be important for spintronics. Recently, we demonstrated a long distance spin transport over 16 µm and spin lifetimes up to 1.2 ns in large area CVD graphene at room temperature [4]. In order to achieve an efficient spin injection into graphene, we used h-BN tunnel barriers with large tunnel spin polarization up to 65 % at room temperature [5]. Recently, we demonstrated all–electrical spin field effect transistor (spin-FET) by employing graphene/MoS2 heterostructures at room temperature [6]. We further electrically detected novel spin current in topological insulators due to spin-momentum locking phenomenon at room temperature [7]. These findings open a platform for exploring novel spin functionalities in 2D materials heterostructures and understanding the basic phenomenon control their behavior. [1] SP Dash, S Sharma, RS Patel, MP de Jong, R Jansen; Nature 462 (7272), 491 (2009). [2] R Jansen, BC Min, SP Dash; Nature materials 9 (2), 133 (2010). [3] SP Dash et al., Physical Review B 84 (5), 054410 (2011). [4] MV Kamalakar, G. Chris, A Dankert, SP Dash; Nature Communication, 6, 6766 (2015). [5] MV Kamalakar, A Dankert, P. Kelly, SP Dash; Scientific Reports, 6, 21168 (2016). [6] A Dankert, SP Dash; arXiv:1610.06326 (2016). Under review in Nature Nano. [7] A Dankert, J. Geur, MV Kamalakar, S Charpentier, SP Dash; Nano Letters 15 (12) 7976 (2015).
Title: Combine and Conquer
Speaker: Satyajit Seth, Johannes Gutenberg-Universitat Mainz
Venue: IOP Lecture Hall
Date: 2017-Jan-13 16:00:00
Abstract: In this talk, I would present how beneficial a rightful combination could be: (i) in achieving local integrability of subtraction terms, (ii) in studying signal simulation of heavy colored particles. I would explain how to group together various NLO subtraction terms to make them locally integrable and how to combine single and pair production of heavy colored particles in new physics searches. The former would be advantageous for numerical approaches in higher-order calculations employing subtraction terms, while the later could be useful to get new information about model parameters and/or better exclusion limits.
Title: Brighter side of semiconductor nanocrystals: How to make defects useful
Speaker: Prof. D D Sarma, Solid State & Structural Chemistry Unit , Indian Institute of Science , Bengaluru 560012, I ndia
Venue: Lecture Hall - 5, NISER
Date: 2017-Jan-13 16:00:00
Abstract: One of the most exciting properties of semiconductor nanoparticles is the spectacular photoluminescence that has the potential to revolutionise the lighting technology. The early excitement was based on the realisation that quantum size effect can be made use of to tune the bandgap and therefore the excitonic emission across the visible range with suitable choices of the nanoparticle size.It was also found that the quantum efficiency of such samples in the dilute limit was often surprisingly high. However,self-absorption as well as susceptibility to surface degradation are known to drastically affect the quantum efficiency of such bandgap emissions, posing a challenge to technological utilisations of these materials. Dopants, particulary Mn in II-VI semiconductors, represent point defects that are known to have negligible self-absorption and resistance to degradation via surface reactions. These advantages were realised at the cost of a near impossibility of tunability of the Mn emission till we recently introduced a novel way to achieve thiscounter-intuitive tunability from an atomic defect.1,2,3In our search for such novel approaches to achieve tunable PL emissions from semiconductor nanoparticles without the disadvantage of any self-absorption, we have been intrigued by the question whether other forms of defects can alsobe meaningfully used to serve the purpose. The presence of defects, primarily surface defects, in semiconductor nanocrystals has been recognized as one of the major deterrents to achieve improved photoluminescence properties.Though it provides a Stokes’ shifted PL emission,it affects adversely our ability to control the emission wavelength and to improve the photoluminescence efficiency. In addition to point defects, I shall present our preliminary theoretical results and some experimental realisations of using “protectedâ€, extended defects in semiconductor nanoparticles for interesting PL properties.4 References: 1.Hazarika A, Layek A, De S, Nag A, Debnath S, Mahadevan P, Chowdhury A, and Sarma D D, Phys. Rev. Lett.2013, 110, 267401. 2.Hazarika A, Pandey A, and Sarma D. D., J. Phys. Chem. Lett.2014, 5,2208. 3.Hazarika A et al., Unpublished results. 4.Das S et al., Unpublished results
Title: Neutron production at small tandem & future perspective
Speaker: Dr. P.K.Rath, INFN, Italy
Venue: IOP Lecture Hall
Date: 2016-Dec-19 16:03:00
Abstract: Neutron production is very much important [1]. Two-body reactions are a convenient and powerful mean to select mono energetic neutrons. A dedicated beam line for neutron production was developed by using the reaction D(d,n)3He [2,3]at the tandem accelerator complex TTT-3 located in the Department of Physics of the University of Naples. The production rate can go up to 105 s-1 over 4 pi. Deuterons can be accelerated up to 6 MeV and the neutron energy and angle can be selected by detecting the associated particle 3He in coincidence. This neutron beam line can be used for a wide range of applications.Details will be provided at the presentation.
Title: Clustering effects and decay analysis of the light mass N=Z and N≠ Z composite systems formed in heavy ion collisions
Speaker: Prof. Bir Bikram Singh, Department of Physics,Sri Guru Granth Sahib World University, Punjab
Venue: IOP Lecture Hall
Date: 2016-Dec-06 16:00:00
Abstract: We investigate the clustering effects in light mass N=Z and N≠Z composite systems 20Ne*, 28Si*, 40Ca* and 21,22Ne*, 39K*, respectively, formed in low energy heavy ion reactions at different excitation energies, within the collective clusterization approach of the dynamical cluster-decay model (DCM) of Gupta and collaborators based on quantum mechanical fragmentation theory (QMFT). Considering quadrupole deformated and compact orientated nuclei, a comparative decay analysis of these systems has been undertaken for the emission of different intermediate mass fragments (IMFs)/clusters, specifically the IMFs having Z=3, 4 and 5 (or Z=7, 6 and 5 complimentary fragments from the 20Ne* and 21,22Ne* composite systems) which are having the experimental data available for their Z-distribution. Quite interestingly, the QMFT supports clustering in N=Z (20Ne*, 28Si*) and N≠Z (21,22Ne*) nuclear systems at excitation energies corresponding to their respective decay thresholds/resonant-state energies for the 4α, 16O cluster and non- α cluster 14C (more so in 22Ne* N≠Z composite system), supported by the Ikeda diagrams, taking into account the proper pairing strength in the temperature dependent liquid drop energies. Within the DCM, we notice that at higher excitation energies in addition to xα (where x is an integer) type clusters from N=Z composite systems and xn-xα type clusters from N≠Z composite systems, np-xα type clusters are relatively quite dominant, with larger preformation probability due to the decreased pairing strength at higher temperatures in the liquid drop energies. Also, the study reveals the presence of competing reaction mechanisms of compound nucleus (fusion-fission, FF) and of non-compound nucleus origin (deep inelastic orbiting, DIO) in the decay of very light mass composite systems 20,21,22Ne* and 28Si* at different excitation energies. The DIO contribution in the IMFs cross section σIMFs is extracted for these composite systems, which is given as the sum of FF cross section σFF and DIO cross section σDIO. The DCM calculated FF cross-sections are in good agreement with the available experimental data.
Title: DFT Theory and Applications
Speaker: Prof. M.P.Das, Australian National University
Venue: IOP Lecture Hall
Date: 2016-Dec-14 16:00:00
Abstract:
Title: What is Dielectric Enhancement and Why
Speaker: Prof. Pabitra Sen, Department of Physics and Astronomy, University of North Calorina
Venue: IOP Lecture Hall
Date: 2016-Nov-23 16:00:00
Abstract:
Title: Magneto - Electric Effects in Hydrogen Atom
Speaker: Prof. T.Pradhan, Ex-Director,IOP
Venue: IOP Lecture Hall
Date: 2016-Nov-08 16:00:00
Abstract:
Title: Probing the Universe With Absorption Lines
Speaker: Prof. Raghunathan Srianand, IUCAA , Pune
Venue: NISER-Bhubaneswar, Jatni- LH-5
Date: 2016-Nov-02 10:30:00
Abstract: Absorption lines seen in the spectra of high-z QSOs allow one to probe the cosmology, galaxy formation and its evolution. In particular absorption lines can be used to study the evolution of different forms of matter, chemical enrichment and ionizing radiation as a function of cosmic time. In addition one will be able to place stringent constraints on the variations of fundamental constants. In this talk the speaker will review the present status of the field and summarize future programmes.
Title: CMB from EFT
Speaker: Dr. Sayantan Choudhury, Department of Theoretical Physics, Tata Institute of Fundamental Research, Mumbai
Venue: IOP Lecture Hall
Date: 2016-Oct-26 16:00:00
Abstract: In this work, we study the Effective Field Theory (EFT) of inflation for quasi single field which describes the most general theoretical framework for quantum fluctuations around a quasi de Sitter background. Based on the time dependent spatial diffeomorphism, which is not broken by the time dependent background evolution, the most generic action is constructed with lowest dimensional Wilsoinan EFT operators up to third order in fluctuations in unitary gauge. Using this setup, further we compute the the two point function (power spectrum) and three point function (bispectrum) for scalar fluctuations using In-In (Swinger Keldysh) formalism. In particular, we discuss two limiting shape configurations in momentum space - equilateral limit and squeezed limit from three point function (bispectrum) for scalar fluctuations. Additionally, we also provide the results for two point function (power spectrum) for tensor (graviton) fluctuations. Finally, using the results for the three point function (bispectrum) for scalar fluctuations we compute the analytical expressions for the Wilsoinan EFT coefficients for canonical single field slow roll models of inflation and general single field models of inflation ($P(X,phi)$ theory which includes any possible form of non-canonical interactions. Example: DBI inflation and Tachyon inflation in String Theory) in the equilateral and squeezed limiting configurations.
Title: Electron states, charge and spin transport in low dimensional systems
Speaker: Dr. Biplab Pal, Kalyani University
Venue: IOP Library Lecture Hall
Date: 2016-Oct-20 16:00:00
Abstract: In this talk, the nature of single electron states and the corresponding quantum transport properties in certain low dimensional tight-binding model systems will be discussed. Real space renormalization group (RSRG) decimation technique and the transfer matrix method (TMM) have been employed to bring out some interesting localization-delocalization features of electronic states in such simple model systems with quasiperiodic and fractal geometries. The idea of spin transport and spin filters for higher order spin states in addition to the spin 1/2 case in model magnetic chain systems will also be addressed.
Title: Time: Sunrise and Sunset Time
Speaker: Prof. H. S. Mani, CMI, Chennai
Venue: Room 014, SBS Building, IIT Bhubaneswar, Argul, Jatni
Date: 2016-Oct-07 16:00:00
Abstract: The time of sun rise and sun set at a given latitude and longitude will be obtained and compared with observation.
Title: Bell's Inequality - Lecture 3
Speaker: Prof. H. S. Mani, CMI, Chennai
Venue: Room 014, School of Basic Sciences (SBS) building, IIT Bhubaneswar, Argul
Date: 2016-Oct-06 14:00:00
Abstract:
Title: Bell's Inequality - Lecture 2
Speaker: Prof. H. S. Mani, CMI, Chennai
Venue: Room 014, School of Basic Sciences (SBS) building, IIT Bhubaneswar, Argul
Date: 2016-Oct-05 14:00:00
Abstract:
Title: Bell's Inequality - Lecture 1
Speaker: Prof. H. S. Mani, CMI, Chennai
Venue: Room 014, School of Basic Sciences (SBS) building, IIT Bhubaneswar, Argul
Date: 2016-Oct-04 14:00:00
Abstract:
Title: From Clusters to Crystals: A Bottom-up Design of Energy Materials
Speaker: Prof. Purusottam Jena, Physics Department, Virginia Commonwealth University, Richmond, VA 23284-2000, USA
Venue: Room 014, SBS Building, IIT Bhubaneswar, Argul, Jatni
Date: 2016-Oct-03 10:00:00
Abstract: Clean, abundant, and sustainable energy is undoubtedly one of the greatest challenges in the 21 st century. Fossil fuels that account for more than 80% of the current world’s need are not only limited but also are harmful to the environment. While solar, wind, and hydrogen together can meet the world’s energy needs, considerable material challenges remain before they can replace our dependence on fossil fuels. I will outline some of the material challenges in energy storage and conversion with particular emphasis on hydrogen storage [1], Li-ion batteries [2-4], and perovskite solar cells [5]. A common feature of all these materials is that they are complex salts whose negative ion components can be identified as superhalogen clusters that mimic the chemistry of halogens. This realization has made it possible to use the vast advances in cluster science to design novel materials for energy applications. I will discuss how superhalogens can help us synthesize halogen-free electrolytes for Li, Na, and Mg-ion batteries [2-4], enable focused discovery of durable hybrid perovskite solar cells [5], understand the intermediate phases [6] during de-hydrogenation of complex metal borohydrides, and design safer materials capable of storing large amounts of hydrogen [7]. These results based on density functional theory have predictive capability. Examples of experimental verification of some of the predicted results will be presented. 1. P. Jena: “Materials for Hydrogen Storage: Past, Present, and Futureâ€, J. Phys. Chem. Letters 2, 206 (2011). 2. S. Giri, S. Behera, and P. Jena: “Superhalogens as Building Blocks of Halogen-free Electrolytes in Li-ion Batteriesâ€, Angew. Chem. Int. Ed. 53, 13916 (2014); 3. Zhao, J. Zhou, and P. Jena, “Stability of B 12 (CN) 12 2- : Implications for Lithium and Magnesium Ion Batteriesâ€, Angew. Chem. Int. Ed. (VIP) 55, 3704 (2016) 4. P. Jena, Superhalogens: A Bridge between Complex Metal Hydrides and Li-ion Batteries. J. Phys. Chem. Letters 6, 1119 (2015). 5. H. Fang and P. Jena, “Super-ion Inspired Colorful Hybrid Perovskite Solar Cellsâ€, J. Mat. Chem. A 4, 4728 (2016) 6. Y. Liu, S. Giri, J. Zhou, and P. Jena: “Intermediate phases during decomposition of metal borohydrides, M(BH 4 ) n (M=Na, Mg, Y)â€, J. Phys. Chem. C 118, 28456 (2014) 7. D. A. Knight, R., Zidan, R. Lascola, R. Mohtadi, C. Ling, P. K. Sivasubramaniam, J. A. Kaduk, S. -J. , Hwang, D. Samanta, and P. Jena.: “Stabilization of Hydrogen Rich, Yet Highly Pyrophoric Al(BH 4 ) 3 via the Synthesis of the Hypersalt K[Al(BH 4 ) 4 ]â€, J. Phys. Chem. C 117, 19905 (2013)
Title: Introduction: Bell's Inequality
Speaker: Prof. H. S. Mani, Chennai Mathematical Institute, Chennai
Venue: Room 014, SBS Building, IIT Bhubaneswar, Argul, Jatni
Date: 2016-Oct-03 11:30:00
Abstract: Series of 6-8 lectures on Bell's inequality: Tentative plan is as follows. 1. Bell's inequality and Bell's theorem 2. Bell's theorem without inequalities ( Mermin's derivation) 3. Bell ,Clauser Horne,Shimony and Holt inequality 4. Legget Garg inequalities 5. Werner states and mathematics of entanglement 6. The power of entanglement 7 Experimental verification of B-CHSH inequalities
Title: Landau Singularity and the Perturbative Series in QED
Speaker: Prof. Mofazzal Azam, BARC, Mumbai (Retired)
Venue: IOP Lecture Hall
Date: 2016-Sep-30 16:00:00
Abstract:
Title: Holography, Second Law and Higher Curvature Gravity.
Speaker: Prof. Sudipta Sarkar, IIT Gandhinagar
Venue: IOP Lecture Hall
Date: 2016-Sep-27 16.00
Abstract:
Title: Geroch Group in Einstein Spaces
Speaker: Prof.Prasanta Tripathy, IIT, Chennai
Venue: IOP Lecture Hall
Date: 2016-Sep-26 16:00:00
Abstract:
Title: Frustration effects in lattice models of polymers
Speaker: Prof.Damien Foster, Coventry university, UK
Venue: IOP Lecture Hall
Date: 2016-Sep-21 16:00:00
Abstract: I will start by outlining how to model dilute models of polymers on a lattice, and introduce the concept of Universality. Concentrating on two dimensional lattice models, I will present the use of transfer matrix techniques and their extensions to calculating the thermodynamic behaviour of the model as well as the main accepted results. Whilst simple arguments lead one to believe that the behaviour of lattice models should not depend on the fine details of the model, this turns out not always to be the case. I will discuss a few models where the concept of Universality appears to be broken.
Title: Quest for a Unified Theory
Speaker: Prof. Sudhakar Panda, Director, Institute of Physics, Bhubaneswar
Venue: Room 004, SBS Building, IIT Bhubaneswar, Argul-Jatni, Bhubaneswar
Date: 2016-Sep-08 16:00:00
Abstract: In this talk, we will review our modern understanding of the building blocks of matter and their interactions. We will motivate the necessity of one unified quantum theory to describe all the interactions. We will critically examine the pros and cons of a candidate, called String Theory, for this purpose
Title: DNA Unzipping and protein-DNA interactions
Speaker: Dr. Garima Mishra, Physics Department, IIT Kanpur
Venue: IOP Lecture Hall
Date: 2016-Sep-14 16:00:00
Abstract: DNA determines the identity of living organisms, and its processing inside the cells involves complex molecular machinery. Reducing the complex description of this machinery to the simple one, this talk will discuss our recent efforts to study the processing of DNA: mainly the separation of its two strands and the subsequent protection of the newly generated strands by single stranded DNA binding proteins.
Title: Light Higgs Bosons at the LHC
Speaker: Prof. Monoranjan Guchait , TIFR, Mumbai
Venue: IOP Lecture Hall
Date: 2016-Sep-09 16:00:00
Abstract: The recent data indicates that the observed Higgs boson of mass ~ 125 GeV at the LHC experiments is very likely to be the SM-like. However, beyond standard model physics can also accommodate this SM like Higgs boson. For example, the supersymmetic extension of the SM, e.g. the minimal supersymmetric extension of the standard model(MSSM) offers one of its Higgs boson as the SM-like, but this model requires too much fine tuning of the parameters space and, is also severely constrained. On the other hand, the next to the MSSM (NMSSM) can accommodate the SM-like Higgs boson very easily without much tuning of its parameters. The interesting consequence of this model is that it predicts more Higgs bosons in addition to the SM like Higgs boson and, some of them can be very light, even at the level of few GeV. In this talk, after reviewing recent Higgs results,I plan to discuss the NMSSM Higgs phenomenology in the context of the LHC Run 2 experiments.
Title: Morphology dictated heterogeneous dynamics in two-dimensional aggregates
Speaker: Dr. Tamoghna Das, University of Maryland, USA
Venue: IOP Lecture Hall
Date: 2016-Aug-23 11:00:00
Abstract: Two-dimensional (2D) particulate aggregates formed due to competing interactions exhibit a range of non-equilibrium steady state morphologies from finite-size compact crystalline structures to non-compact string-like conformations. We report a transition in heterogeneous microscopic dynamics across this morphological hierarchy as a function of decreasing long-range repulsion relative to short-range attraction at a constant low density and temperature. Following a `slow' cooling protocol to form steady state aggregates, we show that geometric frustration inherent to competing interactions assures non-ergodicity of the system, which in turn results in long-time sub diffusive relaxation. Analyzing individual particle trajectories generated by molecular dynamics, we identify caging dynamics of particles in compact clusters in contrast to the bonding scenario for non-compact ones. Finally, by monitoring temperature dependence of the same fixed density system, we present a generic relation between diffusivity and structural randomness of the aggregates, irrespective of their thermodynamic equilibrium.
Title: Tensionless superstrings from worldsheet perspective
Speaker: Shankhdeep Chakrabortty, Groningen,Netherlands
Venue: IOP Lecture Hall
Date: 2016-Aug-18 11:00:00
Abstract:
Title: Cosmological Inflation, Primordial Magnetic Fields and their non-Guassian imprints
Speaker: Dr. Rajeev Kumar Jain , CP3 Origins, Denmark
Venue: IOP Lecture Hall
Date: 2016-Aug-22 16:00:00
Abstract: I will start with a brief introduction to cosmological inflation and the observational evidence for cosmic magnetic fields. I will then outline various mechanisms for generation of primordial magnetic fields from inflation and discuss the constraints arising from the strong coupling, backreaction and the anisotropies due to the induced bispectrum of the generated magnetic fields for the simplest gauge invariant model of inflationary magnetogenesis. In the second part of my talk, I will discuss non-Gaussian imprints of cosmic magnetic fields by means of a cross-correlation between the primordial curvature perturbations and magnetic fields. Such a correlation serves as a new contribution to the non-Gaussian signatures induced by primordial magnetic fields. We obtain a simple consistency relation for this cross-correlation in the squeezed limit while the signal is maximized for the flattened configuration where the magnetic non-linear parameter becomes large. Towards the end, I will also discuss primordial magnetogenesis in a non-singular bouncing scenario wherein a scale invariant spectrum of magnetic fields can be obtained.
Title: Avalanches in Nonequilibrium Random-field Ising Model (RFIM)
Speaker: Diana Thongjaomayum , NEHU, Shillong
Venue: IOP Lecture Hall
Date: 2016-Aug-16 16:00:00
Abstract: The response of a complex system to a slowly and smoothly varying force sometimes becomes jerky eg. earthquakes, avalanches, Barkhausen noise etc. Such behaviour is studied using a minimal model: the RFIM. The general criteria for the occurrence of nonequilibrium critical behaviour on Bethe lattices and studies on some periodic lattices in the framework of RFIM shall be discussed.
Title: Study of fission dynamics and nuclear viscosity (Ashwini Rath Memorial Colloquium)
Speaker: Dr. Yogesh Kumar Gupta , BARC, Mumbai
Venue: IOP Lecture Hall
Date: 2016-Aug-11 16:00:00
Abstract: Understanding of fission dynamics has been a topic of continued research interest. Among many other degrees of freedom, nuclear viscosity plays a crucial role in governing the fission dynamics. Several probes have been previously employed to study the fission dynamics and hence the nuclear viscosity. Certain issues about the nuclear viscosity such as its nature, temperature and coordinate dependence etc. remain unresolved. We have employed a different approach to gain information about the nuclear viscosity. Near scission particle emission (ternary fission) is very sensitive to nuclear motion during saddle to scission points and actual tearing up of the neck. I will discuss the systematic study of pre-scission and near scission α-particle emission made for various systems over a wide range of Z2/A and excitation energies. We find an important piece of information about the nuclear collective motion which has direct bearing on nuclear viscosity.
Title: Brighter side of Semiconductor Nanocrystals: How to make Defects useful
Speaker: Prof. D. D. Sarma, Solid State and Structural Chemistry Unit, IISc Bangalore
Venue: Room 004, SBS Building, IIT Bhubaneswar, Argul Campus, Jatni.
Date: 2016-Aug-11 16:00:00
Abstract: One of the most exciting properties of semiconductor nanoparticles is the spectacular light it emits when excited, a phenomenon known as photoluminescence that has the potential to revolutionise the lighting technology. The early excitement was based on the realisation that quantum effects can be made use of to tune this emission across the visible range by tailoring the size of such pure nanoparticles. However, self-absorption as well as susceptibility to surface degradation are known to drastically affect the efficiency of such emissions, posing a challenge to technological utilisations of these materials. I shall discuss the counterintuitive approach based on deliberate insertion of point and extended defects in nanoparticles to overcome those intrinsic drawbacks of the pure system and to bring these materials closer to practical applications.
Title: Active Matter
Speaker: Prof. Sriram Ramaswamy, TCIS, Hyderabad
Venue: Lecture Hall, NISER
Date: 2016-Sep-06 16:15:00
Abstract:
Title: Institution building: The story of IISER's
Speaker: Prof. N. Sathyamurthy, Director, IISER Mohali
Venue: Lecture Hall, NISER
Date: 2016-Sep-06 15:00:00
Abstract: To be announced
Title: New Paradigms in active Matter: Heat Engine, Flocking and Sorting
Speaker: Prof. Ajay Sood, Department of Physics, IISc, Bangalore
Venue: NISER Lecture Hall
Date: 2016-Aug-29 16:00:00
Abstract: To be announced
Title: Electric Dipole Moment of the Electron: Probe of New Physics Beyond the Standard Model
Speaker: Prof. Bhanu Pratap Das, Tokyo Institute of Technology, Japan
Venue: IOP Lecture Hall
Date: 2016-Aug-12 16:00:00
Abstract: The electric dipole moment (EDM) of the electron which arises due to the violations of the parity and time-reversal symmetries is a very sensitive probe of new physics beyond the Standard Model of particle interactions. My talk will focus on the manifestation of the EDM of the electron in atoms and molecules. The combined role of atomic/molecular experiment and theory in obtaining the electron EDM will be emphasized. The current status for the search of the electron EDM and its implications for new physics beyond the Standard Model will be highlighted.
Title: Surprises with DNA
Speaker: Prof. Somendra M Bhattacharjee, Institute of Physics (IOP), Bhubaneswar
Venue: IOP Lecture Hall
Date: 2016-Aug-10 16:00:00
Abstract: Double stranded DNA has several unusual properties not shown by simple polymers or even single strands of DNA. Nevertheless, there are similarities between certain classes of problems of condensed matter physics (CMP) and the behaviour of DNA. Examples are melting of DNA, its rigidity, and associated topological issues. This talk will focus on some of these broad analogies between DNA and CMP.