



@article {1737,
	title = {Collective phases of strongly interacting cavity photons},
	journal = {Physical Review A},
	volume = {94},
	year = {2016},
	month = {2016/09/01},
	pages = {033801},
	abstract = {<p>We study a coupled array of coherently driven photonic cavities, which maps onto a driven-dissipative XY spin-12 model with ferromagnetic couplings in the limit of strong optical nonlinearities. Using a site-decoupled mean-field approximation, we identify steady state phases with canted antiferromagnetic order, in addition to limit cycle phases, where oscillatory dynamics persist indefinitely. We also identify collective bistable phases, where the system supports two steady states among spatially uniform, antiferromagnetic, and limit cycle phases. We compare these mean-field results to exact quantum trajectories simulations for finite one-dimensional arrays. The exact results exhibit short-range antiferromagnetic order for parameters that have significant overlap with the mean-field phase diagram. In the mean-field bistable regime, the exact quantum dynamics exhibits real-time collective switching between macroscopically distinguishable states. We present a clear physical picture for this dynamics, and establish a simple relationship between the switching times and properties of the quantum Liouvillian.</p>},
	doi = {http://dx.doi.org/10.1103/PhysRevA.94.033801},
	url = {http://arxiv.org/abs/1601.06857},
	author = {Ryan M. Wilson and Khan W. Mahmud and Anzi Hu and Alexey V. Gorshkov and Mohammad Hafezi and Michael Foss-Feig}
}
@article {1299,
	title = {Counterflow and paired superfluidity in one-dimensional Bose mixtures in  optical lattices
},
	journal = {Physical Review A},
	volume = {80},
	year = {2009},
	month = {2009/8/24},
	abstract = {  We study the quantum phases of mixtures of ultra-cold bosonic atoms held in
an optical lattice that confines motion or hopping to one spatial dimension.
The phases are found by using Tomonaga-Luttinger liquid theory as well as the
numerical method of time evolving block decimation (TEBD). We consider a binary
mixture with repulsive intra-species interactions, and either repulsive or
attractive inter-species interaction. For a homogeneous system, we find paired-
and counterflow-superfluid phases at different filling and hopping energies. We
also predict parameter regions in which these types of superfluid order coexist
with charge density wave order. We show that the Tomonaga-Luttinger liquid
theory and TEBD qualitatively agree on the location of the phase boundary to
superfluidity. We then describe how these phases are modified and can be
detected when an additional harmonic trap is present. In particular, we show
how experimentally measurable quantities, such as time-of-flight images and the
structure factor, can be used to distinguish the quantum phases. Finally, we
suggest applying a Feshbach ramp to detect the paired superfluid state, and a
$\pi/2$ pulse followed by Bragg spectroscopy to detect the counterflow
superfluid phase.
},
	doi = {10.1103/PhysRevA.80.023619},
	url = {http://arxiv.org/abs/0906.2150v1},
	author = {Anzi Hu and L. Mathey and Ippei Danshita and Eite Tiesinga and Carl J. Williams and Charles W. Clark}
}
