520 research outputs found
Nernst effect and diamagnetic response in a stripe model of superconducting cuprates
We examine the possibility that the experimentally observed enhancement of
superconducting (SC) fluctuations above the SC transition temperature in the
underdoped cuprates is caused by stripes -- an intrinsic electronic
inhomogeneity, common to hole-doped cuprates. By evaluating the strengths of
the diamagnetic response and the Nernst effect within the striped SC model, we
find results that are qualitatively consistent with the experimental
observations. We make a prediction for anisotropic thermopower in detwinned
samples that can be used to further test the proposed scenario.Comment: 5 pages, 3 figures; final version published in Europhysics Letter
Topological Frequency Conversion in a Driven Dissipative Quantum Cavity
Recent work (PRX 7, 041008) has shown that a spin coupled to two externally
supplied circularly-polarized electromagnetic modes can effectuate a
topological, quantized transfer of photons from one mode to the other. Here we
study the effect in the case when only one of the modes is externally provided,
while the other is a dynamical quantum mechanical cavity mode. Focusing on the
signatures and stability under experimentally accessible conditions, we show
that the effect persists down to the few-photon quantum limit and that it can
be used to generate highly entangled "cat states" of cavity and spin. By tuning
the strength of the external drive to a "sweet spot", the quantized pumping can
arise starting from an empty (zero photon) cavity state. We also find that
inclusion of external noise and dissipation does not suppress but rather
stabilizes the conversion effect, even after multiple cavity modes are taken
into account.Comment: 12 pages, 6 figure
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