SAIFR:4792

From disorder to order and back again

(2024). From disorder to order and back again. ICTP South American Institute for Fundamental Research. https://scivideos.org/ictp-saifr/4792

From disorder to order and back again. ICTP South American Institute for Fundamental Research, Nov. 06, 2024, https://scivideos.org/ictp-saifr/4792 

          @misc{ scivideos_SAIFR:4792,
            doi = {},
            url = {https://scivideos.org/ictp-saifr/4792},
            author = {},
            keywords = {ICTP-SAIFR, IFT, UNESP},
            language = {en},
            title = {From disorder to order and back again},
            publisher = { ICTP South American Institute for Fundamental Research},
            year = {2024},
            month = {nov},
            note = {SAIFR:4792 see, \url{https://scivideos.org/ictp-saifr/4792}}
          }
José Hoyos
Talk numberSAIFR:4792
Source RepositoryICTP – SAIFR
Collection
Talk Type Conference
Subject

Abstract

One surprising phenomenon in frustrated magnets is the order-by-disorder mechanism: thermal and/or quantum fluctuations lift a macroscopic accidental degeneracy of the classical ground state of frustrated magnets. The resulting magnetically ordered-by-(thermal/quantum)disorder state often breaks a real-space symmetry of the crystal lattice. In this talk, we use symmetry arguments, perturbation theory, and Monte Carlo simulations to pedagogically introduce the order by disorder mechanism on the J1-J2 Heisenberg model on a square lattice and to the easy-plane pyrochlores. In addition, we investigate the effects of impurities (vacancies, chemical doping, etc.) on the resulting ordered state. Because inhomogeneities generically break real-space symmetries, it couples to the order-parameter as a conjugate field. Consequently, non-perturbative effects destabilize the ordered-by-disorder state at sufficiently low dimensions preempting any phase transition.