186 research outputs found
Pairing in Asymmetrical Fermi Systems with Intra- and Inter-Species Correlations
We consider inter- and intra-species pairing interactions in an asymmetrical
Fermi system. Using equation of motion method, we obtain coupled mean-field
equations for superfluid gap functions and population densities. We construct a
phase diagram across BCS-BEC regimes. Due to intra-species correlations, the
BCS singlet superfluid state can sustain finite polarizations, . For larger
, we find phase separations in BCS and BEC regimes. A superfluid phase
exists for all deep in BEC regime. Our results may apply to pairing in
ultracold fermions, nuclear and quark matter physics.Comment: Contents revised. Added reference
P-wave Pairing in Two-Component Fermi Systems with Unequal Population near Feshbach Resonance
We explore p-wave pairing in a single-channel two-component Fermi system with
unequal population near Feshbach resonance. Our analytical and numerical study
reveal a rich superfluid (SF) ground state structure as a function of
imbalance. In addition to the state , a
multitude of ``mixed'' SF states formed of linear combinations of 's
give global energy minimum under a phase stability condition; these states
exhibit variation in energy with the relative phase between the constituent gap
amplitudes. States with local energy minimum are also obtained. We provide a
geometric representation of the states. A =0 polarization vs. p-wave
coupling phase diagram is constructed across the BEC-BCS regimes. With
increased polarization, the global minimum SF state may undergo a quantum phase
transition to the local minimum SF state.Comment: 5 pages, 3 figure
Correlation-temperature phase diagram of prototypical infinite layer rare earth nickelates
The discovery of superconductivity in hole-doped infinite layer nickelates,
RNiO2 (R = Nd, Pr, La) has garnered sustained interest in the field. A
definitive picture of low-energy many-body states has not yet emerged. We
provide new insights into the low-energy physics, based on our embedded
dynamical mean-field theory calculations, and propose a correlation
(U)-temperature (T) phase diagram. The key features are a low-T Fermi liquid
(FL) phase, a high-T Curie-Weiss regime, and an antiferromagnetic phase in a
narrow U-T region. We associate the onset of the FL phase with partial
screening of Ni-d moments; however, full screening occurs at lower
temperatures. This may be related to insufficiency of conduction electrons to
effectively screen the Ni-d moments, suggestive of Nozieres Exhaustion
Principle. Our results suggest that RNiO2 are in the paramagnetic state, close
to an antiferromagnetic dome, making magnetic fluctuations feasible. This may
be consequential for superconductivity.Comment: 19 pages, 18 figure
Medium effects close to s- and p-wave Feshbach resonances in atomic Fermi gases
Many-body effects may influence properties, such as scattering parameters,
nature of pairing, etc., close to a Feshbach resonance in the fermion BEC-BCS
crossover problem. We study effects such as these using a tractable
crossing-symmetric approach. This method allow us to include quantum
fluctuations, such as, density, current, spin, spin-current and the
higher-order fluctuations in a self-consistent fashion. The underlying fermion
interaction is reflected in the "driving" term. We perform calculations here on
both Bose-Einstein condensate (BEC) and BCS sides, and taking the driving term
to be finite range, and of arbitrary strength. These are related to two-body
singlet and triplet scattering parameters, and can be connected with
experimental s- and p-wave Feshbach resonances. We include the density
and spin fluctuations, as well as current and spin-current
fluctuations. We calculate renormalized scattering amplitudes, pairing
amplitudes, nature of pairing, etc., on both the BEC and BCS sides. We then
compare our results qualitatively with experiments.Comment: 6 pages, 7 figures. arXiv admin note: text overlap with
arXiv:cond-mat/0607045 by other author
The treatment of achalasia patients with esophageal varices: an international study
Background: Treatment options for achalasia include endoscopic and surgical techniques that carry the risk of esophageal bleeding and perforation. The rare coexistence of esophageal varices has only been anecdotally described and treatment is presumed to carry additional risk.
Methods: Experience from physicians/surgeons treating this rare combination of disorders was sought through the International Manometry Working Group.
Results: Fourteen patients with achalasia and varices from seven international centers were collected (mean age 61 9 years). Five patients were treated with botulinum toxin injections (BTI), four had dilation, three received peroral endoscopic myotomy (POEM), one had POEM then dilation, and one patient underwent BTI followed by Heller’s myotomy. Variceal eradication preceded achalasia treatment in three patients. All patients experienced a significant symptomatic improvement (median Eckardt score 7 vs 1; p < 0.0001) at 6 months follow-up, with treatment outcomes resembling those of 20 non- cirrhotic achalasia patients who underwent similar therapy. No patients had recorded complications of bleeding or perforation.
Conclusion: This study shows an excellent short-term symptomatic response in patients with esophageal achalasia and varices and demonstrates that the therapeutic outcomes and complications, other than transient encephalopathy in both patients who had a portosystemic shunt, did not differ to disease-matched patients without varices
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