Physical Science Colloquium 2017

Physical Science Colloquium 2017

[ 2015 ] [ 2016 ] [ 2018 ]

May 17, 2017	Prof. Sumit Das Univ. of Kentucky, USA. Venue & Time: C V Raman Hall at 4:00 PM HOLOGRAMS, QUANTUM QUENCH AND COSMOLOGY HOLOGRAMS, QUANTUM QUENCH AND COSMOLOGY Over the last couple of decades it has become clear that in many situations gravity can be thought of as an emergent, "dual" description of non-gravitational gauge theories in lower number of dimensions. This realization is a key ingredient in our current understanding of the quantum physics of black holes in terms of the properties of the underlying gauge theory. In the other direction, this duality has been used to address difficult issues in strongly coupled field theories, by mapping them to classical problems in gravity. This talk will discuss the physical origins of this duality and its modern applications to the understanding of far from equilibrium properties of strongly coupled systems, and attempts to uncover the mysteries of big-bang like singularities.
March 15, 2017	Amit Dutta Affiliation: I.I.T Kanpur Venue & Time: C V Raman Hall at 4:00 PM Dynamics of closed quantum systems Dynamics of closed quantum systems The dynamics of closed quantum systems are important and possess new emergent phenomena with respect to their equilibrium counterparts. In this talk, a brief introduction to periodically driven systems will be provided. Furthermore, the talk will focus on the emergence of non-analyticities in the early time dynamics of (ramped or suddenly) driven systems which are now known as dynamical quantum phase transitions (DQPTs). Providing a basic introduction to topology and topological models, we shall illustrate how an emergent topological structure appears in the subsequent temporal evolution of the system following a quench.
February 22, 2017	Rajesh Ganapathy, JNCASR, Bangalore Venue & Time: C V Raman Hall at 3:30 PM Exploiting Shape-sensitive Interactions in Colloidal Suspensions - From Directed Self-assembly to Structural Glasses Exploiting Shape-sensitive Interactions in Colloidal Suspensions - From Directed Self-assembly to Structural Glasses Colloidal suspensions comprise of micrometer-sized particles that remain suspended in a fluid by Brownian motion. Their large size, typically a micron, allows for the investigation of dynamics at the single-particle level using relatively simple tabletop experimental techniques. This feature combined with the tunability of particle shape and interactions makes them promising candidates to address a plethora of problems in statistical mechanics and condensed matter. Apart from their role as model systems, periodic arrangements of colloidal particles have typical lattice spacing comparable to the wavelength of visible light. Thus, colloidal crystals Bragg-scatter visible light and this feature is exploited in the design of photonic band-gap and optoelectronic devices. In my talk, I will describe recent results from our group that exploit the shape-sensitive nature of attractive depletion interactions to address issues in colloidal self-assembly and structural glasses [1-5]. 1. Chandan K Mishra, A K Sood and Rajesh Ganapathy, Proc. Natl. Acad. Sci. U.S.A. 113, 12094 (2016) 2. Shreyas Gokhale, A K Sood and Rajesh Ganapathy, Advances in Physics 65, 363 (2016) 3. Chandan K Mishra and Rajesh Ganapathy, Phys. Rev. Lett. 114, 198302 (2015) 4. Chandan K Mishra, Hima K Nagamanasa, Rajesh Ganapathy, A K Sood and Shreyas Gokhale, Proc. Natl. Acad. Sci. U.S.A. 111, 15362 (2014) 5. Chandan K Mishra, Amritha Rangarajan and Rajesh Ganapathy, Phys. Rev. Lett. 110, 188301 (2013)
January 25, 2017	N. G. Deshpande, University of Orgeon, USA Venue & Time: C V Raman Hall at 4:00 PM Presence of Matter in the Universe-An Unresolved Puzzle Presence of Matter in the Universe-An Unresolved Puzzle In this general talk we review the great puzzle of presence of matter and the amount of it in the Universe. In a perfectly symmetric universe matter and antimatter created at the Big Bang should completely disappear later leaving only radiation. The resolution to the puzzle needs among other conditions, violation of a symmetry called CP. In this talk we review great experimental strides taken to prove CP is violated. Nevertheless the amount of matter present is still an unsolved problem. What future experimental strides are planned that may resolve this issue are discussed.
January 11, 2017	M. Bhattacharya, Rochester Institute of Technology, USA Venue & Time: C V Raman Hall at 4:00 PM Levitated Optomechanics: Phonon cooling, bistability and lasing Levitated Optomechanics: Phonon cooling, bistability and lasing In this talk I will first introduce the subject of cavity optomechanics, which involves the interaction of electromagnetic modes with mechanical oscillators. Subsequently, I will describe the emerging field of levitated optomechanics. Theoretical results on the topic will be reported from our group at RIT, in the context of ongoing experiments in various groups, especially that of our collaborator A. N. Vamivakas at the University of Rochester. Phenomena such as cooling, bistability and phonon lasing will be considered.

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