Abstract
We consider many-body quantum systems on a finite lattice, where the Hilbert
space is the tensor product of finite-dimensional Hilbert spaces associated
with each site, and where the Hamiltonian of the system is a sum of local
terms. We are interested in proving uniform bounds on various properties as the
size of the lattice tends to infinity. An important case is when there is a
spectral gap between the lowest state(s) and the rest of the spectrum which
persists in this limit, corresponding to what physicists call a ``phase of
matter". Here, the combination of elementary Fourier analysis with the
technique of Lieb-Robinson bounds (bounds on the velocity of propagation) is
surprisingly powerful. We use this to prove exponential decay of connected
correlation functions, a higher-dimensional Lieb-Schultz-Mattis theorem, and a
Hall conductance quantization theorem for interacting electrons with disorder.
Users
Please
log in to take part in the discussion (add own reviews or comments).