School of Physical Sciences
Jawaharlal Nehru University
SPS Seminar on
Quantum Phase Transitions and Singular Behavior in Spin-Glasses [1]
Speaker: Prof. Rajiv Singh
University of California at Davis
Date: September 2, 2022 Time: 4:00 PM
Venue: Seminar Hall, SPS
Abstract: We discuss ground state phase behavior of Ising spin-glasses in a transverse field. Quantum phase transitions from the paramagnetic phase to a spin-glass phase are studied for the quantum Sherrington-Kirkpatrick (SK) model as well as on d-dimensional hypercubic lattices. The critical behavior in high dimensions agrees with the SK model, whereas it deviates sharply in lower dimensions. Below d=4, Griffiths-McCoy singularities become prominent in the paramagnetic phase and can lead to observable singularities in spin-glass susceptibility with continuously varying exponents before the thermodynamic phase transition to the spin-glass phase takes place. Estimates of critical exponents at the thermodynamic phase transition in d=2 and d=3 will be presented.
[1] Based on work done in collaboration with A. P. Young