Generalized lattice Wilson-Dirac fermions in (1+1) dimensions for atomic quantum simulation and topological phases

The Dirac fermion is an important fundamental particle appearing in high-energy physics and topological insulator physics. In particular, a Dirac fermion in a one-dimensional lattice system exhibits the essential properties of topological physics. However, the system has not been quantum simulated in experiments yet. Herein, we propose a one-dimensional generalized lattice Wilson-Dirac fermion model and study its topological phase structure. We show the experimental setups of an atomic quantum simulator for the model, in which two parallel optical lattices with the same tilt for trapping cold fermion atoms and a laser-assisted hopping scheme are used. Interestingly, we find that the model exhibits nontrivial topological phases characterized by gapless edge modes and a finite winding number in the broad regime of the parameter space. Some of the phase diagrams closely resemble those of the Haldane model. We also discuss topological charge pumping and a lattice Gross-Neveu model in the system of generalized Wilson-Dirac fermions.Comment: 14 pages, 7+1 figures, accepted for publication in Scientific Report

Real time dynamics and proposal for feasible experiments of lattice gauge-Higgs model simulated by cold atoms

Lattice gauge theory has provided a crucial non-perturbative method in studying canonical models in high-energy physics such as quantum chromodynamics. Among other models of lattice gauge theory, the lattice gauge-Higgs model is a quite important one because it describes wide variety of phenomena/models related to the Anderson-Higgs mechanism such as superconductivity, the standard model of particle physics, and inflation process of the early universe. In this paper, we first show that atomic description of the lattice gauge model allows us to explore real time dynamics of the gauge variables by using the Gross-Pitaevskii equations. Numerical simulations of the time development of an electric flux reveal some interesting characteristics of dynamical aspect of the model and determine its phase diagram. Next, to realize a quantum simulator of the U(1) lattice gauge-Higgs model on an optical lattice filled by cold atoms, we propose two feasible methods: (i) Wannier states in the excited bands and (ii) dipolar atoms in a multilayer optical lattice. We pay attentions to respect the constraint of Gauss's law and avoid nonlocal gauge interactions.Comment: 13 pages, 7 figure

Cryptochrome and Period Proteins Are Regulated by the CLOCK/BMAL1 Gene: Crosstalk between the PPARs/RXRα-Regulated and CLOCK/BMAL1-Regulated Systems

Feeding and the circadian system regulate lipid absorption and metabolism, and the expression of enzymes involved in lipid metabolism is believed to be directly controlled by the clock system. To investigate the interaction between the lipid metabolism system and the circadian system, we analyzed the effect of a CLOCK/BMAL1 heterodimer on the transcriptional regulation of PPAR-controlled genes through PPAR response elements (PPREs). Transcription of acyl-CoA oxidase, cellular retinol binding protein II (CRBPII), and 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase was altered by CLOCK/BMAL1, and transcriptional activity via PPRE by PPARs/RXRα was enhanced by CLOCK/BMAL1 and/or by PPARs ligand/activators. We also found that CLOCK/BMAL1-mediated transcription of period (PER) and cryptochrome (CRY) was modulated by PPARα/RXRα. These results suggest that there may be crosstalk between the PPARs/RXRα-regulated system and the CLOCK/BMAL1-regulated system

Experimental Study on Mitigation of Liquefaction-Induced Lateral Displacement Deep Soil Mixing

After 1990s\u27 earthquakes in Japan, lateral flow of liquefiable slopes became a serious concern of engineers. Espisally Kobe earthquake (1995) in which high subsidence of river levee as a result of liquefied sand lateral flow was observed, become a turning point in geotechnical engineering approach in dealing with this phenomena. From that time many different kinds of mitigation measures for preventing or at least controlling the extent of lateral flow have been proposed. Improving soil by deep mixing columns is one of the common methods of soil improvement that can also be used for controlling the consequences of liquefied sand flow. For analyzing the factors affecting the efficiency of this method, several shaking table tests have been done. This article is showing the effects of studied factors including columns pattern the length and improvement ratio. Moreover the magnitude of flow inside and outside of improved area are scrutinized. Finally, based on experimental observations, behavior of liquefied sand in existence of deep mixed soil is modeled numerically

Mammary tissue microenvironment determines T cell-dependent breast cancer-associated inflammation

Although the importance of the host tissue microenvironment in cancer progression and metastasis has been established, the spatiotemporal process establishing a cancer metastasis-prone tissue microenvironment remains unknown. In this study, we aim to understand the immunological character of a metastasis-prone microenvironment in a murine 4T1 breast tumor model, by using the activation of nuclear factor-jb (NF-jB) in cancer cells as a sensor of inflammatory status and by monitoring its activity by bioluminescence imaging. By using a 4T1 breast cancer cell line stably expressing an NF-jB ⁄ Luc2 reporter gene (4T1 NF-jB cells), we observed significantly increased bioluminescence approximately 7 days after metastasis-prone orthotopic mammary fat-pad inoculation but not ectopic s.c. inoculation of 4T1 NF-jB cells. Such in vivo NF-jB activation within the fat-pad 4T1 tumor was diminished in immune-deficient SCID or nude mice, or T celldepleted mice, suggesting the requirement of host T cell-mediated immune responses. Given the fat-pad 4T1 tumor expressed higher inflammatory mediators in a T cell-dependent mechanism compared to the s.c. tumor, our results imply the importance of the surrounding tissue microenvironment for inflaming tumors by collaborating with T cells to instigate metastatic spread of 4T1 breast cancer cells

SHORT DIGITAL STRESS SCALE - PSYCHOMETRIC PROPERTIES AND CROSS-CULTURAL VALIDATION

Due to the massive, global, and seemingly unabated growth in mobile and social media use, across private and work lives, users likely experience perceived digital stress, which might undermine important behavioural outcomes. Hall et al. (2021) have established a digital stress scale (DSS), developed among U.S. adolescents and young adults; the current study offers a cross-cultural test of the scale and proposes a shortened version, by almost 60%. Social media use tends to blur work and nonwork spheres, and psychometric scales need to be cross-culturally valid, so the present study tests perceived digital stress among employees from three countries. The well-established validation procedures and samples from Germany, Italy, and Japan affirm the reliability, validity, and cross- national applicability of a 10-item short DSS. The extended application also reveals the impact of perceived digital stress on three sets of employee outcomes. In turn, this research offers implications for both IS research and practice