Strong pairing from small Fermi surface beyond weak coupling: Application to La3_3Ni2_2O7_7

The studies of high-temperature superconductors raise a fundamental question: Can a small Fermi surface phase, which violates the Luttinger theorem, exist and give rise to superconductivity? Our work provides a positive answer through a controlled theory based on a bilayer model with strong inter-layer spin-spin coupling ($J_\perp$) but no inter-layer hopping ($t_\perp$). Then small hole doping of the rung-singlet insulator with two electrons per rung naturally leads to small hole pockets with Fermi surface volume per flavor smaller than the free fermion result by $1/2$ of the Brillouin zone(BZ). We construct a new t-J model on a bilayer square lattice, so called ESD t-J model and employ a generalized slave boson theory, which captures this small Fermi surface phase at small hole doping $x$. This metallic state is an intrinsically strongly correlated Fermi liquid beyond weak coupling theory, violating the perturbative Luttinger theorem but consistent with the Oshikawa's non-perturbative proof. We further show that it transitions into an inter-layer paired $s'$-wave superconductor at lower temperature through Feshbach resonance with a virtual Cooper pair, with a surprising doping-induced crossover from Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensation (BEC) at higher hole doping levels. This leads to a superconducting dome centered around $x=0.5$, with the normal state changing from the conventional Fermi liquid in the $x>0.5$ to the unusual small Fermi surface state in the $x<0.5$ side. Our theoretical findings including phase diagrams are also confirmed by density matrix renormalization group (DMRG) simulation in quasi one dimension. Applying our theoretical framework, we provide a plausible scenario for the recently found nickelate La$_3$Ni$_2$O$_7$ materials.Comment: 11+13 pages, 8+13 figur

Deconfined criticalities and dualities between chiral spin liquid, topological superconductor and charge density wave Chern insulator

We propose bi-critical and tri-critical theories between chiral spin liquid (CSL), topological superconductor (SC) and charge density wave (CDW) ordered Chern insulator with Chern number $C=2$ on square, triangular and kagome lattices. The three CDW order parameters form a manifold of $S^2$ or $S^1$ depending on whether there is easy-plane anisotropy. The skyrmion defect of the CDW order carries physical charge $2e$ and its condensation leads to a topological superconductor. The CDW-SC transitions are in the same universality classes as the celebrated deconfined quantum critical points (DQCP) between Neel order and valence bond solid order on square lattice. Both SC and CDW order can be accessed from the CSL phase through a continuous phase transition. At the CSL-SC transition, there is still CDW order fluctuations although CDW is absent in both sides. We propose three different theories for the CSL-SC transition (and CSL to easy-plane CDW transition): a $U(1)$ theory with two bosons, a $U(1)$ theory with two Dirac fermions, and an $SU(2)$ theory with two bosons. Our construction offers a derivation of the duality between these three theories as well as a promising physical realization. The $SU(2)$ theory offers a unified framework for a series of fixed points with explicit $SO(5), O(4)$ or $SO(3)\times O(2)$ symmetry. There is also a transparent duality transformation mapping SC order to easy-plane CDW order. The CSL-SC-CDW tri-critical points are invariant under this duality mapping and have an enlarged $SO(5)$ or $O(4)$ symmetry. The DQCPs between CDW and SC inherit the enlarged symmetry, emergent anomaly, and self-duality from the tri-critical point. Our analysis unifies the well-studied DQCP between symmetry breaking phases into a larger framework where they are proximate to a topologically ordered phase.Comment: 30+7 pages, 9 figures, 11 table

A Study Of Online Beauty Community Members\u27 Voices: EWOM Text Mining

The Internet promotes the development of the social media, these new media offer open platforms for participants to share product/service reviews with each other. This study applied the theory of conformity behavior to explain online community members’ information consumption behaviors by using text-mining techniques. NetBeans7.4 was used to conduct Chinese tokenization and data analysis. Next, factor analysis and correlation analysis were conducted to reduce the attribute size of products. Our findings demonstrate that more attributes a product/brand has more discussions found in an online community. The conformity phenomenon is seen in help to accumulate sufficient and complete eWOM to reach a sufficient quantity. Thus, brand is more likely to be mentioned. However, the few brand vendors with high product strength have the impact of conformity, in which, may result in a lower spread power with wrong marketing strategy. Therefore, we argue that the reputation bias generated by conformity will make a misleading purchase decision. Based on the conformity effect of eWOM, we establish the effectiveness of text mining technology applied to information search platform design and brand marketing strategy. Implications were proposed in the final section

Badanie zależności między metylacją regionu promotora genu MMP-9 a nefropatią cukrzycową

Objective: This study aims to explore the relationship between the methylation of matrix metalloproteinase (MMP)-9 gene promoter region and diabetic nephropathy (DN) through the detection of the methylation level of MMP-9 gene promoter region in the peripheral blood of patients with DN in different periods and serum MMP-9 concentration. Methods: The methylation level of the MMP-9 gene promoter region was detected by methylation-specific polymerase chain reaction (MSP), and the content of MMP-9 in serum was determined by enzyme-linked immunosorbent assay (ELISA). Results: Results of the statistical analysis revealed that serum MMP-9 protein expression levels gradually increased in patients in the simple diabetic group, early diabetic nephropathy group and clinical diabetic nephropathy group, compared with the control group; and the difference was statistically significant (P < 0.05). Compared with the control group, the methylation levels of MMP-9 gene promoter regions gradually decreased in patients in the simple diabetic group, early diabetic nephropathy group, and clinical diabetic nephropathy group; and the difference was statistically significant (P < 0.05). Furthermore, correlation analysis results indicated that the demethylation levels of the MMP-9 gene promoter region was positively correlated with serum protein levels, urinary albumin to creatinine ratio (UACR), urea and creatinine; and was negatively correlated with GFR. Conclusion: The demethylation of the MMP-9 gene promoter region may be involved in the occurrence and development of diabetic nephropathy by regulating the expression of MMP-9 protein in serum.Wstęp: Celem pracy jest zbadanie zależności między metylacją regionu promotora genu metaloproteinazy macierzy zewnątrzkomórkowej typu 9 a nefropatią cukrzycową, poprzez wykrycie poziomu metylacji regionu promotora genu MMP-9 we krwi obwodowej pacjentów z nefropatią cukrzycową w różnych okresach i przy różnym stężeniu MMP-9 w surowicy krwi. Materiał i metody: Poziom metylacji regionu promotora genu MMP-9 wykrywano za pomocą metylospecyficznej reakcji łańcuchowej polimerazy (methylation-specific polymerase chain reaction; MSP), natomiast zawartość MMP-9 w surowicy krwi była określana przy użyciu enzymatycznego testu immunoadsorpcyjnego (ELISA). Wyniki: Wyniki analizy statystycznej wykazały, że poziom ekspresji białka MMP-9 w surowicy krwi stopniowo wzrastał w grupie pa­cjentów ze zwykłą cukrzycą, w grupie pacjentów z wczesną nefropatią cukrzycową oraz w grupie z kliniczną nefropatią cukrzycową w porównaniu z grupą kontrolną; różnica była statystycznie istotna (p &lt; 0,05). W porównaniu z grupą kontrolną poziom metylacji regionów promotora genu MMP-9 stopniowo się zmniejszał w grupie pacjentów ze zwykłą cukrzycą, w grupie pacjentów z wczesną nefropatią cukrzycową oraz w grupie z kliniczną nefropatią cukrzycową; różnica była istotna statystycznie (p &lt; 0,05). Ponadto, wyniki analizy korelacji wykazały, że poziomy demetylacji regionu promotora genu MMP-9 były dodatnio skorelowane ze stężeniem białek w surowicy krwi, ze wskaźnikiem albumina/kreatynina (urinary albumin to creatinine ratio; UACR), mocznikiem i kreatyniną oraz były ujemnie skorelowane ze wskaźnikiem GFR. Wnioski: Demetylacja regionu promotora genu MMP-9 może być zaangażowana w występowanie i rozwój nefropatii cukrzycowej poprzez regulację ekspresji białka MMP-9 w surowicy krwi.

Phase transitions out of quantum Hall states in moir\'e TMD bilayers

Motivated by the recent experimental breakthroughs in observing Fractional Quantum Anomalous Hall (FQAH) states in moir\'e Transition Metal Dichalcogenide (TMD) bilayers, we propose and study various unconventional phase transitions between quantum Hall phases and Fermi liquids or charge ordered phases upon tuning the bandwidth. At filling $\nu=-\frac{2}{3}$, we describe a direct transition between the FQAH state and a Charge Density Wave (CDW) insulator. The critical theory resembles that of the familiar deconfined quantum critical point(DQCP) but with an additional Chern-Simons term. At filling $\nu=-\frac{1}{2}$, we study the possibility of a continuous transition between the composite Fermi liquid (CFL) and the Fermi liquid (FL) building on and refining previous work by Barkeshli and McGreevy. Crucially we show that translation symmetry alone is enough to enable a second order CFL-FL transition. We argue that there must be critical CDW fluctuations though neither phase has long range CDW order. We present experimental signatures the most striking of which is a universal jump of both longitudinal and Hall resistivities at the critical point. With disorder, we argue that the CDW order gets pinned and the CFL-FL evolution happens through an intermediate electrically insulating phase with mobile neutral fermions. A clean analog of this insulating phase with long range CDW order and a neutral fermi surface can potentially also exist. We discuss the properties of this phase and the nature of its phase transitions. We also present a critical theory for the CFL to FL transition at filling $\nu=-\frac{3}{4}$. Our work opens up a new avenue to realize deconfined criticalities and fractionalized phases beyond familiar Landau level physics in the moir\'e Chern band system.Comment: 17+3 page

The development status of specialized nursing in ostomy care both in China and abroad

AbstractThe status of ostomy-specialized nurses' training and the specialized care for patients with permanent colostomy both in China and abroad are analyzed. Based on features and characteristics of the development of ostomy care outside China, problems in China's ostomy care are discussed to promote the sustainable development of this type of care

Distance-aware Attention Reshaping: Enhance Generalization of Neural Solver for Large-scale Vehicle Routing Problems

Neural solvers based on attention mechanism have demonstrated remarkable effectiveness in solving vehicle routing problems. However, in the generalization process from small scale to large scale, we find a phenomenon of the dispersion of attention scores in existing neural solvers, which leads to poor performance. To address this issue, this paper proposes a distance-aware attention reshaping method, assisting neural solvers in solving large-scale vehicle routing problems. Specifically, without the need for additional training, we utilize the Euclidean distance information between current nodes to adjust attention scores. This enables a neural solver trained on small-scale instances to make rational choices when solving a large-scale problem. Experimental results show that the proposed method significantly outperforms existing state-of-the-art neural solvers on the large-scale CVRPLib dataset