Shortcuts in Real and Imaginary Time

          @misc{ pirsa_PIRSA:19070027,
            doi = {10.48660/19070027},
            url = {https://pirsa.org/19070027},
            author = {Hsieh, Timothy},
            keywords = {Condensed Matter},
            language = {en},
            title = {Shortcuts in Real and Imaginary Time},
            publisher = {Perimeter Institute},
            year = {2019},
            month = {jul},
            note = {PIRSA:19070027 see, \url{https://pirsa.org}}
          }
          

Abstract

In the first half, I will demonstrate an efficient and general approach for realizing non-trivial quantum states, such as quantum critical and topologically ordered states, in quantum simulators. In the second half, I will present a related variational ansatz for many-body quantum systems that is remarkably efficient. In particular, representing the critical point of the one-dimensional transverse field Ising model only requires a number of variational parameters scaling logarithmically with system size. Though optimizing the ansatz generally requires Monte Carlo sampling, our ansatz potentially enables a partial mitigation of the sign problem at the expense of having to optimize a few parameters.