Seminar: Bhaskaran Muralidharan
We describe two distinct applications of quantum dots [1-3] from a quantum transport perspective. In the first part, we bring in a Bayesian viewpoint to the analysis of clocks, specifically taking the Salecker Wigner clock formulation [4] and explore a novel set up to estimate the tunneling time [1] between electrons in a contact and a quantum dot weakly coupled to it. Using the exponential tunneling distribution as 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. We then proceed to briefly discuss quantum dot heat engines [3] which can be driven by classical and quantum information and present interesting results such as the violation of Carnot limit related to information driven heat engines.
References:
[1] M Gopalkrishnan, V. Kandula, P. Sriram, A. Deshpande and B. Muralidharan, Phys. Rev. A, 96, 032339, (2017).
[2] B. De and B. Muralidharan, Phys. Rev. B, 94, 165416, (2016).
[3] A. Shah, S. Vinjanampathy and B. Muralidharan, ArXiv: 1706.04299, (2017).
[4] A. Peres, Am. J. Phys., 48, 552, (1980).
Speaker biography
Dr. Bhaskaran Muralidharan obtained his B.Tech in Engineering Physics from the Indian Institute of technology (IIT) Bombay in 2001, his M. S. and Ph. D in Electrical Engineering from Purdue University, West Lafayette in 2003 and 2008 respectively. Between 2008-2012, he was a post-doctoral associate at the Massachusetts Institute of Technology (MIT) and at the Institute for theoretical Physics at the University of Regensburg, Germany. Since December 2015, he is an Associate Professor at the Department of Electrical Engineering at IIT Bombay, India. He is currently involved in the physics and simulation of non-equilibrium phenomena in a variety of systems including nanodevices, nano and spin thermoelectrics and fundamental limits of modern computation. He was also the recipient of the APS-IUSSTF professorship award in 2014.