Hidden String Order in a Hole Superconductor with Extended Correlated Hopping.
Ultracold fermions in one-dimensional, spin-dependent nonoverlapping optical lattices are described by a nonstandard Hubbard model with next-nearest-neighbor correlated hopping. In the limit of a kinetically constraining value of the correlated hopping equal to the normal hopping, we map the invariant subspaces of the Hamiltonian exactly to free spinless fermion chains of varying lengths. As a result, the system exactly manifests spin-charge separation and we obtain the system properties for arbitrary filling: ground state collective order characterized by a spin gap, which can be ascribed to an unconventional critical hole superconductor associated with finite long range nonlocal string order. We study the system numerically away from the integrable point and show the persistence of both long range string order and spin gap for appropriate parameters as well as a transition to a ferromagnetic state.
ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Av. Carl Friedrich Gauss 3, 08860 Barcelona, Spain.|Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland.
Ravindra W
RW
Chhajlany
Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland.
Przemysław R
PR
Grzybowski
ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Av. Carl Friedrich Gauss 3, 08860 Barcelona, Spain.|Institute of Physics of the Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland.
Julia
J
Stasińska
ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Av. Carl Friedrich Gauss 3, 08860 Barcelona, Spain.|ICREA-Institució Catalana de Recerca i Estudis Avançats, Lluis Campanys 23, 08010 Barcelona, Spain.
Maciej
M
Lewenstein
Instytut Fizyki im. M. Smoluchowskiego, Uniwersytet Jagielloński, Łojasiewicza 11, 30-348 Kraków, Poland.|Donostia International Physics Center DIPC, Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastian, Spain.
Omjyoti
O
Dutta