Alleviating the sign structure of quantum states

          @misc{ scivideos_PIRSA:19070022,
            doi = {10.48660/19070022},
            url = {https://pirsa.org/19070022},
            author = {Torlai, Giacomo},
            keywords = {Quantum Matter},
            language = {en},
            title = {Alleviating the sign structure of quantum states},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2019},
            month = {jul},
            note = {PIRSA:19070022 see, \url{https://scivideos.org/pirsa/19070022}}
          }
          

Abstract

The sign structure of quantum states - the appearance of “probability” amplitudes with negative sign - is one of the most striking contrasts between the classical and the quantum world, with far-reaching implications in condensed matter physics and quantum information science. Because it is a basis-dependent property, one may wonder: is a given sign structure truly intrinsic, or can it be removed by a local change of basis? In this talk, I will present an algorithm based on automatic differentiation of tensor networks for discovering non-negative representations of many-body wavefunctions. I will show some numerical results for ground states of a two-leg triangular Heisenberg ladder, including an exotic Bose-metal phase.