The photo-excited state associated with superconducting fluctuation above the superconducting critical temperature $T_c$ is studied based on the time-dependent Ginzburg-Laundau approach. The excited state is created by an electric-field pulse and is probed by a weak secondary external field, which is treated by the linear response theory mimicking pump-probe spectroscopy experiments. The behavior is basically controlled by two relaxation rates: one is $γ_1$ proportional to the temperature measured from the critical point $T - T_c$ and the other is $γ_2$ proportional to the excitation intensity of the pump pulse. The excited state approaches the equilibrium state exponentially in a long time $t \gg γ_1^{-1}$, while in the intermediate time domain we find a power-law or logarithmic decay with different exponents for $t\ll γ_2^{-1}$ and $γ_2^{-1} \ll t \ll γ_1^{-1}$, even though the system is located away from the critical point. This is interpreted as the critical point in equilibrium being extended to a finite region in the excited situation. The parameter dependences on both the pump and probe currents are also systematically studied in all dimensions.
We present a framework for analyzing Mott insulators using a material-based tight-binding model. We start with a realistic multiorbital Hubbard model and derive an effective model for the localized electrons through the second-order perturbation theory with respect to intersite hopping. This effective model, known as the Kugel-Khomskii model, is described by SU($N$) generators, where $N$ is the number of localized states. We solve this model by the mean-field theory that takes local correlations into account and reveal spin-orbital ordered states. To include spatial correlations, we apply the classical Monte Carlo based on the path-integral approach with SU($N$) coherent states, and also derive the equation of motion for spin-orbital degrees of freedom. Our approach is applicable to any Mott insulator with reasonable computational cost. The $5d$-pyrochlore oxide is used here as demonstration.
The disorder and interaction effects on Bogoliubov-Fermi surfaces with preserved inversion symmetry are studied for a low-energy effective model coupled to bosonic degrees of freedom. It is shown that the non-ideal Bogoliubov quasiparticles (bogolons) generically induce the odd-frequency pair amplitude which reflects a Cooper pairing at different time. The self-energy of bogolons is mainly contributed by the disorder effects in the low frequency limit as in the usual electron liquid. Depending on the choice of the parameters, there are two kinds of solutions: one is frequency-independent (but with sign function of frequency) and the other is proportional to the inverse of the frequency, which exist in both the normal and anomalous parts of the self-energy. These characteristic self-energy structures are clearly reflected in the single-particle spectrum. Since the bogolons are originally composed of electrons, the connection between the two is also sought using the concrete $j=3/2$ fermion model, which reveals that the odd-frequency pairing of bogolons is mainly made of the electrons' odd-frequency pairing.
Low mean nocturnal baseline impedance (MNBI) values support gastroesophageal reflux disease (GERD) diagnosis. Recent data denote that age and obesity may affect MNBI. We aimed to evaluate diagnostic MNBI cutoffs as also the effect of aging and body mass index (BMI) on MNBI.In total 311 patients (M/F: 139/172, mean age: 47 ± 13) referred for typical GERD symptoms that have undertaken both high-resolution manometry (HRM) and pH-Impedance studies off PPI were evaluated. MNBI at 3, 5, and 17 cm over lower esophageal sphincter (LES) were evaluated. GERD was diagnosed if acid exposure time (AET) >6%.Mean BMI was 26.6 ± 5.9 kg/cm2 . GERD was diagnosed in 39.2% and 13.5% had inconclusive GERD. MNBI was correlated to patients' age, BMI, AET, and the length of LES-CD separation and at 3 cm also to the total number of reflux and LES hypotension. In the multivariate analysis MNBI at 3 and 5 cm was independently correlated only to age, BMI, and AET. Patients with definite GERD showed lower MNBI at 3 cm compared with inconclusive GERD though both showed lower values when compared with GERD absence. At 3 cm MNBI ability for diagnosing GERD was good (0.815, p < 0.001 95% CI: 0.766-0.863) with an optimal cutoff point of 1281 Ohm.According to our study findings age and BMI affect independently lower esophageal MNBI values in patients evaluated for GERD. MNBI significantly aids toward GERD diagnosis though in a real-life setting MNBI values much lower than the one previously proposed should be used.
Odd-frequency Cooper pairs with chiral symmetry emerging at the edges of topological superconductors are a useful physical quantity for characterizing the topological properties of these materials. In this work, we show that the odd-frequency Cooper pair amplitudes can be expressed by a winding number extended to a nonzero frequency, which is called a ``spectral bulk-boundary correspondence,'' and can be evaluated from the spectral features of the bulk. The odd-frequency Cooper pair amplitudes are classified into two categories: the amplitudes in the first category have the singular functional form $\ensuremath{\sim}1/z$ (where $z$ is a complex frequency) that reflects the presence of a topological surface Andreev bound state, whereas the amplitudes in the second category have the regular form $\ensuremath{\sim}z$ and are regarded as nontopological. We discuss the topological phase transition by using the coefficient in the latter category, which undergoes a power-law divergence at the topological phase transition point and is used to indicate the distance to the critical point. These concepts are established based on several concrete models, including a Rashba nanowire system that is promising for realizing Majorana fermions.
Abstract Background and Aim Previous studies on age differences in proton pump inhibitor (PPI)‐resistant reflux esophagitis (RE) have found that stenosis and bleeding complications were significantly more common in the elderly than in the non‐elderly. We sought to examine differences between two groups of elderly (75 years or older) and non‐elderly (<75 years) patients with (PPI)‐resistant severe RE and also the efficacy of vonoprazan (VPZ) in these patients. Methods There were 14 patients in the elderly group and 15 in the non‐elderly group. Information was obtained on patient background (sex, body mass index [BMI], gastric mucosal atrophy, and the presence of hernia and collagen disease), and all patients underwent the saliva secretion test and esophagogastroduodenoscopy (EGD). The saliva secretion test (amount of saliva secreted, salivary pH, and the acid‐buffering capacity) was performed by chewing sugar‐free gum for 3 min before EGD. The efficacy of VPZ in both groups was also assessed. Results Saliva secretion, sex, BMI, and the presence of gastric mucosal atrophy did not significantly differ between the two groups. The number of hernias larger than 4 cm was significantly higher in the elderly PPI‐resistant group, and significantly more patients had collagen disease in the non‐elderly group. The efficacy of VPZ was not significantly different between the two groups; however, 10 patients in the non‐elderly group had collagen disease, and 4 did not achieve esophageal mucosal healing even with VPZ 20 mg. Conclusion The number of large hernias (>4 cm) was significantly higher in the elderly group, while significantly more non‐elderly patients had collagen disease. In the non‐elderly group with scleroderma, the efficacy of VPZ 20 mg may not be sufficient.
It was recently pointed out that Fermi surfaces can survive even in superconductors. Here, the authors study the instability of such systems toward electronic ordering. The ordered states are classified into diagonal and off-diagonal ones, which, respectively, indicate the Pomeranchuk instability and Cooper pairing not of original electrons but of Bogoliubov particles (bogolons). The corresponding order parameters are expanded by multipole moments and multiplet pair amplitudes of original electrons. These results provide insights into superconductors with multiple phase transitions.
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