Motivated by recent experimental advances in ultracold atoms, we analyze a non-Hermitian (NH) BCS Hamiltonian with a complex-valued interaction arising from inelastic scattering between fermions. We develop a mean-field theory to obtain a NH gap equation for order parameters, which are different from the standard BCS ones due to the inequivalence of left and right eigenstates in the NH physics. We find unconventional phase transitions unique to NH systems: superfluidity shows reentrant behavior with increasing dissipation, as a consequence of non-diagonalizable exceptional points, lines, and surfaces in the quasiparticle Hamiltonian for weak attractive interactions. For strong attractive interactions, the superfluid gap never collapses but is enhanced by dissipation due to an interplay between the BCS-BEC crossover and the quantum Zeno effect. Our results lay the groundwork for studies of fermionic superfluidity subject to inelastic collisions.
Short-wavelength X-rays (WKcq-2-0.209,~,) have been used to collect higher-order reflections for studies of the electron-density distributions of silicon and diamond with high resolution. The sp 3 bonding electron-density distributions of these materials are visible in the total electron-density maps synthesized by the maximum-entropy method (MEM) and also in the difference MEM maps synthesized by Fourier summation of Fmem(h)-F°re(h), where Fmem(h) is the structure factor calculated from the MEM map and F°re(h) is the structure factor calculated from Si c°re and C c°re models, if very extensive data sets with higherorder reflections are used. These maps are more informative than the conventional difference Fourier map synthesized by Fourier summation of F°bS(h)-F°re(h) using the observed structure factor F°bs(h) instead of Fmem(h). The present maps can be compared with certain band-theory calculations.
In 2005, the SYNTAX score was reported as "an angiographic tool grading the complexity of coronary artery disease". We investigated risk factors for the complexity of coronary artery disease (CAD) using SYNTAX scores in patients with new-onset CAD. The subjects were 359 consecutive cases that underwent de novo percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery without previous PCI history. Acute myocardial infarction was excluded. The SYNTAX scores were obtained from coronary angiographies performed before PCI. On multivariate linear regression analysis of risk factors for the SYNTAX scores, aging, being a male and having diabetes mellitus were identified as significant independent risk factors (age: multiple regression coefficient 0.27, p = 0.001; male: 4.91, p = 0.004; diabetes: 4.53, p = 0.001). Other coronary risk factors such as hypertension, hypercholesterolemia, smoking and reduced renal function were not identified as significant independent risk factors. In patients undergoing PCI, aging, being a male and having diabetes mellitus are considered to be independent risk factors for the complexity of CAD. Therefore, when patients with CAD have these factors, we expect the CAD of the patient to be more complex and that it will be necessary to provide more careful medical care.
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