Breaking ‘is not’ Bad

Speaker: Pratyay Ghosh

Venue : HSB 210

Date : 3rd May, 2019

Time : 5.15 p.m.

Abstract

Frustration is an essential feature that governs the modern day condensed matter physics. A spin system is frustrated when one fails to find a minimum energy configuration which satisfies all the bonds simultaneously. Such a system, in the presence of quantum fluctuations, is known to elude magnetic ordering (despite of the strong interactions among their constituent spin moments) while producing excitingly new disordered phases. By definition, a disordered state obeys the spin-rotation and time-reversal symmetry. An ordered state, on the other hand, breaks both. The prominent examples of the former are the Quantum Spin Liquids, Spin Nematics, Plaquette ordered states, etc. The inherent differences between these different states (and under what circumstances they arise) lie in the different discrete, and continuous symmetries present the interaction Hamiltonian and also the sudden complete/partial breaking of one/more symmetries in the ground state. The talk explores different such situations and exhibits how the complex interplay between these symmetries gives rise to exotic quantum disorder states in frustrated magnets.

About the speaker

Pratyay Ghosh is a theoretical condensed matter physicist, currently working as an Institute PostDoctoral Fellow in the Department of Physics of Indian Institute of Technology Madras. He obtained his Ph.D. from the Jawaharlal Nehru University, New Delhi in 2018. His field of research is the study of exotic ground states in Frustrated Quantum Magnets. He did his masters and bachelors (both in Physics) from Indian Institute of Technology Bombay and Presidency College, Kolkata (currently Presidency University) respectively.