Tangent Space Approach for Thermal Tensor Network Simulations of the 2D Hubbard Model.

Accurate simulations of the two-dimensional (2D) Hubbard model constitute one of the most challenging problems in condensed matter and quantum physics. Here we develop a tangent space tensor renormalization group (tanTRG) approach for the calculations of the 2D Hubbard model at finite temperature. An optimal evolution of the density operator is achieved in tanTRG with a mild O(D^{3}) complexity, where the bond dimension D controls the accuracy. With the tanTRG approach we boost the low-temperature calculations of large-scale 2D Hubbard systems on up to a width-8 cylinder and 10×10 square lattice. For the half-filled Hubbard model, the obtained results are in excellent agreement with those of determinant quantum Monte Carlo (DQMC). Moreover, tanTRG can be used to explore the low-temperature, finite-doping regime inaccessible for DQMC. The calculated charge compressibility and Matsubara Green's function are found to reflect the strange metal and pseudogap behaviors, respectively. The superconductive pairing susceptibility is computed down to a low temperature of approximately 1/24 of the hopping energy, where we find d-wave pairing responses are most significant near the optimal doping. Equipped with the tangent-space technique, tanTRG constitutes a well-controlled, highly efficient and accurate tensor network method for strongly correlated 2D lattice models at finite temperature.

Symmetry-Protected Topological Edge Modes and Emergent Partial Time-Reversal Symmetry Breaking in Open Quantum Many-Body Systems.

Symmetry-protected topological edge modes are one of the most remarkable phenomena in topological physics. Here, we formulate and quantitatively examine the effect of a quantum bath on these topological edge modes. Using the density matrix renormalization group method, we study the ground state of a composite system of spin-1 quantum chain, where the system and the bath degrees of freedom are treated on the same footing. We focus on the dependence of these edge modes on the global and partial symmetries of system-bath coupling and on the features of the quantum bath. It is shown that the time-reversal symmetry (TRS) plays a special role for an open quantum system, where an emergent partial TRS breaking will result in a TRS-protected topological mode diffusing from the system edge into the bath, thus make it useless for quantum computation.

Noise-Driven Universal Dynamics towards an Infinite Temperature State.

Dynamical universality is the observation that the dynamical properties of different systems might exhibit universal behavior that are independent of the system details. In this Letter, we study the longtime dynamics of a one-dimensional noisy quantum magnetic model, and find that even though the system is inevitably driven to an infinite temperature state, the relaxation dynamics towards such a featureless state can be highly nontrivial and universal. The effect of various mode-coupling mechanisms (external potential, disorder, interaction, and the interplay between them) as well as the conservation law on the longtime dynamics of the systems have been studied, and their relevance with current ultracold atomic experiments has been discussed.

A case of lupus miliaris disseminatus faciei that was successfully treated with 595 nm pulsed-dye laser combined with drugs.

Lupus miliaris disseminatus faciei (LMDF) is a rare chronic inflammatory and granulomatous skin disease characterized by reddish-brown papules and nodules on the central face. Although this disease can spontaneously resolve, disfiguring scars can often remain. This disease responds poorly to general treatments. Except for systemic hormones, the efficacy of other drugs is unclear. There are few reports on the use of laser treatment for LMDF. Here, we report a case of LMDF that was successfully treated with a 595 nm pulsed-dye laser combined with glucocorticoids and isotretinoin. The treatment outcome shows less scar formation and fewer side effects when this regimen was employed.

[Identification of a 17q25.3 duplication in a Chinese patient with global developmental delay and multiple congenital anomalies].

OBJECTIVE: To delineate the clinical features,inheritance pattern, and genotype-phenotype correlation of a Chinese patient with a 17q25.3 duplication. METHODS: Whole exome sequencing(WES), chromosomal microarray analysis (CMA), chromosomal karyotyping and fluorescence in situ hybridization (FISH) were employed for the analysis of the proband and his family members. RESULTS: A 5.7 Mb duplication at 17q25.3→qter was identified by WES and CMA in the 4-year-old boy with multiple congenital anomalies, which was classified as a clinically pathogenic variant. This duplication was confirmed by FISH, and was inherited from his unaffected mother who carried a balanced translocation. Further study revealed that his grandmother also carried the balanced translocation but had gestated three healthy children and had no abortion history. His uncle also carried the balanced translocation, while his aunt was normal. CONCLUSION: Above results have enriched the clinical phenotypes of 17q25.3 duplication. Genetic counseling was provided for the family. P4HB, ACTG1, BAIAP2 and TBCD genes may underlie the clinical features for the 17q25.3 duplication.

Study on the Durability of the T-Beam Based on Chloride Ion Erosion.

Based on analyzing the bearing capacity of existing T-beam bridges in service, the factors that affect the T-beams cracked by chloride ions mainly include the width and the depth of cracks. Combined with practical engineering examples, a single-piece T-beam model is established to explore the influence of factors such as crack width and crack depth on the T-beams affected by chloride ion erosion through numerical simulation in this paper. In addition, the attenuation models of bending capacity and shear capacity of the T-beam are obtained to analyze the possible failure modes of T-beams with cracks. All of which provides a reference for exploring the effect of crack width and depth on the durability of reinforced concrete members under chloride ion field.

Prenatal findings and molecular cytogenetic analyses of a de novo interstitial deletion of 1q23.3 encompassing PBX1 gene.

OBJECTIVES: To present the prenatal findings and the molecular cytogenetic analyses of a de novo interstitial deletion of 1q23.3 encompassing PBX1 gene. CASE REPORT: A 32-year-old woman (gravida 1, para 0) underwent amniocentesis at 26 weeks' gestation because of constant small fetal kidneys on prenatal ultrasound. Chromosome microarray analysis (CMA) detected a de novo deletion of 1.871 Mb at 1q23.3. The deletion encompassed 2 genes of PBX1 and LMX1A. PBX1 haploinsufficiency had been reported to lead syndromic congenital anomalies of kidney and urinary tract (CAKUT) in humans. Furthermore, at 31 weeks' gestation, borderline oligohydramnios and restricted fetal dimensions were revealed. Ultimately, the pregnancy was terminated at 32 weeks with a 1500-g female fetus presenting polydactyl of left hand. CONCLUSIONS: The shared phenotypes between this case and the previously published prenatal cases demonstrate that loss of function mutation in PBX1 should be suspicious in fetus with bilateral renal hypoplasia, oligohydramnios and intrauterine growth retardation (IUGR).