Quantum criticality of a Z3\mathbb{Z}_{3} symmetric spin chain with long-range interactions

Based on large-scale density matrix renormalization group techniques, we investigate the critical behaviors of quantum three-state Potts chains with long-range interactions. Using fidelity susceptibility as an indicator, we obtain a complete phase diagram of the system. The results show that as the long-range interaction power $\alpha$ increases, the critical points $f_{c}^{*}$ shift towards lower values. In addition, the critical threshold $\alpha_{c}(\approx 1.43$) of the long-range interaction power is obtained for the first time by a non-perturbative numerical method. This indicates that the critical behavior of the system can be naturally divided into two distinct universality classes, namely the long-range (\alpha \textless \alpha_c) and short-range (\alpha \textgreater \alpha_c) universality classes, qualitatively consistent with the classical $\phi^{3}$ effective field theory. This work provides a useful reference for further research on phase transitions in quantum spin chains with long-range interaction.Comment: 5+7 pages. Any comments or suggestions are welcome

An Evolutionary Computation Based Feature Selection Method for Intrusion Detection

Data Availability: The data used to support the fndings of this study are available from the corresponding author upon request. This work was supported by the National Natural Science Foundation of China (61403206, 61771258, and 61876089), the Natural Science Foundation of Jiangsu Province (BK20141005 and BK20160910), the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (14KJB520025), the Priority Academic Program Development of Jiangsu Higher Education Institutions, the Open Research Fund of Jiangsu Engineering Research Center of Communication and Network Technology, NJUPT (JSGCZX17001), and the Natural Science Foundation of Jiangsu Province of China under Grant BK20140883.Peer reviewedPublisher PD

Non-Hermitian Stark Many-Body Localization

Utilizing exact diagonalization (ED) techniques, we investigate a one-dimensional, non-reciprocal, interacting hard-core boson model under a Stark potential with tail curvature. By employing the non-zero imaginary eigenenergies ratio, half-chain entanglement entropy, and eigenstate instability, we numerically confirm that the critical points of spectral real-complex (RC) transition and many-body localization (MBL) phase transition are not identical, and an examination of the phase diagrams reveals that the spectral RC transition arises before the MBL phase transition, which suggests the existence of a novel non-MBL-driven spectral RC transition. These findings are quite unexpected, and they are entirely different from observations in disorder-driven interacting non-Hermitian systems. This work provides a useful reference for further research on phase transitions in disorder-free interacting non-Hermitian systems.Comment: Any comments or suggestions are welcome

2-Anilino-4,6-dimethyl­pyrimidinium chloro­acetate

In the crystal structure of the title compound, C12H14N3 +·C2H2ClO2 −, the chloro­acetate anion is linked to the N-(4,6-dimethyl­pyrimidin-2-yl)aniline cation by N—H⋯O hydrogen bonding. Within the cation, the pyrimidine ring is twisted with respect to the phenyl ring by a dihedral angle of 7.59 (4)°

Observation of forbidden phonons and dark excitons by resonance Raman scattering in few-layer WS2_2

The optical properties of the two-dimensional (2D) crystals are dominated by tightly bound electron-hole pairs (excitons) and lattice vibration modes (phonons). The exciton-phonon interaction is fundamentally important to understand the optical properties of 2D materials and thus help develop emerging 2D crystal based optoelectronic devices. Here, we presented the excitonic resonant Raman scattering (RRS) spectra of few-layer WS$_2$ excited by 11 lasers lines covered all of A, B and C exciton transition energies at different sample temperatures from 4 to 300 K. As a result, we are not only able to probe the forbidden phonon modes unobserved in ordinary Raman scattering, but also can determine the bright and dark state fine structures of 1s A exciton. In particular, we also observed the quantum interference between low-energy discrete phonon and exciton continuum under resonant excitation. Our works pave a way to understand the exciton-phonon coupling and many-body effects in 2D materials.Comment: 14 pages, 11 figure

Emergent self-duality in long range critical spin chain: from deconfined criticality to first order transition

Over the past few decades, tremendous efforts have been devoted to understanding self-duality at the quantum critical point, which enlarges the global symmetry and constrains the dynamics. In this letter, we employ large-scale density matrix renormalization group simulations to investigate the critical spin chain with long-range interaction $V(r) \sim 1/r^{\alpha}$. Remarkably, we reveal that the long-range interaction drives the deconfined criticality towards a first-order phase transition as $\alpha$ decreases. More strikingly, the emergent self-duality leads to an emergent symmetry and manifests at these first-order critical points. This discovery is reminiscent of self-duality protected multicritical points and provides the example of the critical line with generalized symmetry. Our work has far-reaching implications for ongoing experimental efforts in Rydberg atom quantum simulators.Comment: 5 + 10 pages, 9 figures. Any comments or suggestions are welcome

In situ fabrication of carbon fibre–reinforced polymer composites with embedded piezoelectrics for inspection and energy harvesting applications

Yan, X., Courtney, C. R., Bowen, C. R., Gathercole, N., Wen, T., Jia, Y., & Shi, Y. (2020). In situ fabrication of carbon fibre–reinforced polymer composites with embedded piezoelectrics for inspection and energy harvesting applications. Journal of Intelligent Material Systems and Structures, 31(16), 1910-1919. doi:10.1177/1045389X20942315. Copyright © 2020 (Copyright Holder). Reprinted by permission of SAGE Publications.Current in situ damage detection of fibre-reinforced composites typically uses sensors which are attached to the structure. This may make periodic inspection difficult for complex part geometries or in locations which are difficult to reach. To overcome these limitations, we examine the use of piezoelectric materials in the form of macro-fibre composites that are embedded into carbon fibre–reinforced polymer composites. Such a multi-material system can provide an in situ ability for damage detection, sensing or energy harvesting. In this work, the piezoelectric devices are embedded between the carbon fibre prepreg, and heat treated at elevated temperatures, enabling complete integration of the piezoelectric element into the structure. The impact of processing temperature on the properties of the macro-fibre composites are assessed, in particular with respect to the Curie temperature of the embedded ferroelectric. The mechanical properties of the carbon fibre–reinforced polymer composites are evaluated to assess the impact of the piezoelectric on tensile strength. The performance of the embedded piezoelectric devices to transmit and receive ultrasonic signals is evaluated, along with the potential to harvest power from mechanical strain for self-powered systems. Such an approach provides a route to create multi-functional materials