13 research outputs found
Pairing and Vortex Lattices for Interacting Fermions in Optical Lattices with a Large Magnetic Field
We study the structure of pairing order parameter for spin-1/2 fermions with
attractive interactions in a square lattice under a uniform magnetic field.
Because the magnetic translation symmetry gives a unique degeneracy in the
single-particle spectrum, the wave function has both zero and finite momentum
components co-existing, and their relative phases are determined by a
self-consistent mean-field theory. We present a microscopic calculation that
can determine the vortex lattice structure in the superfluid phase for
different flux densities. Phase transition from a Hofstadter insulator to a
superfluid phase is also discussed.Comment: 4 pages, 3 figures, one table, published versio
Probing few-particle Laughlin states of photons via correlation measurements
We propose methods to create and observe Laughlin-like states of photons in a
strongly nonlinear optical cavity. Such states of strongly interacting photons
can be prepared by pumping the cavity with a Laguerre-Gauss beam, which has a
well-defined orbital angular momentum per photon. The Laughlin-like states
appear as sharp resonances in the particle-number-resolved transmission
spectrum. Power spectrum and second-order correlation function measurements
yield unambiguous signatures of these few-particle strongly-correlated states.Comment: 11 pages including appendice
Fractional Quantum Hall states in the vicinity of Mott plateaus
We perform variational Monte-Carlo calculations to show that bosons in a
rotating optical lattice will form analogs of fractional quantum Hall states
when the tunneling is sufficiently weak compared to the interactions and the
deviation of density from an integer is commensurate with the effective
magnetic field. We compare the energies of superfluid and correlated states to
one-another and to the energies found in full configuration-interaction
calculations on small systems. We look at overlaps between our variational
states and the exact ground-state, characterizing the ways in which fractional
quantum Hall effect correlations manifest themselves near the Mott insulating
state. We explore the experimental signatures of these states.Comment: 6 pages, 4 figure
Bulk density signatures of a lattice quasihole with very few particles
Motivated by the recent experimental realization of a two-particle fractional
quantum Hall state of ultracold atoms in a small optical lattice [Nature 619,
495 (2023)], we propose a minimal setup to create and observe a quasihole in
such a system. Adding a single-site repulsive potential to pin the quasihole
and superimposing a harmonic trap on top of the optical lattice to keep the
particles away from the system edge, we determine via exact diagonalization an
optimal range for system parameters such as the magnetic flux and the strengths
of the additional potentials that would favour the creation of the quasihole
state. We suggest that clear signatures of such a state with two or three
particles can be obtained through a standard density measurement.Comment: 4.5+3 page
Photon condensation in circuit QED by engineered dissipation
We study photon condensation phenomena in a driven and dissipative array of
superconducting microwave resonators. Specifically, we show that by using an
appropriately designed coupling of microwave photons to superconducting qubits,
an effective dissipative mechanism can be engineered, which scatters photons
towards low-momentum states while conserving their number. This mimics a
tunable coupling of bosons to a low temperature bath, and leads to the
formation of a stationary photon condensate in the presence of losses and under
continuous-driving conditions. Here we propose a realistic experimental setup
to observe this effect in two or multiple coupled cavities, and study the
characteristics of such an out-of-equilibrium condensate, which arise from the
competition between pumping and dissipation processes