228 research outputs found
Dimensional crossover and cold-atom realization of topological Mott insulators
We propose a cold-atom setup which allows for a dimensional crossover from a
two-dimensional quantum spin Hall insulating phase to a three-dimensional
strong topological insulator by tuning the hopping between the layers. We
further show that additional Hubbard onsite interactions can give rise to spin
liquid-like phases: weak and strong topological Mott insulators. They represent
the celebrated paradigm of a quantum state of matter which merely exists
because of the interplay of the non-trivial topology of the band structure and
strong interactions. While the theoretical understanding of this phase has
remained elusive, our proposal shall help to shed some light on this exotic
state of matter by paving the way for a controlled experimental investigation
in optical lattices.Comment: 4+ pages, 3 figures; includes Supplemental Material (3 pages, 1
figure
Manipulation of a two-photon pump in superconductor - semiconductor heterostructures
We investigate the photon statistics, entanglement and squeezing of a
pn-junction sandwiched between two superconducting leads, and show that such an
electrically-driven photon pump generates correlated and entangled pairs of
photons. In particular, we demonstrate that the squeezing of the fluctuations
in the quadrature amplitudes of the emitted light can be manipulated by
changing the relative phase of the order parameters of the superconductors.
This reveals how macroscopic coherence of the superconducting state can be used
to tailor the properties of a two-photon state.Comment: 4+ pages, 3 figures; includes Supplemental Material (9 pages, 1
figure). Published versio
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