AAPPS Bulletin最新文献

NASICON (Na(_{1+x})Zr(_2)Si(_x)P(_{3-x})O(_{12})) is a well-established solid-state electrolyte, renowned for its high ionic conductivity and excellent chemical stability, rendering it a promising candidate for solid-state batteries. However, the intricate influence of ion doping on their performance has been a central focus of research, with existing studies often lacking comprehensive evaluation methods. This study introduces a deep-learning-based approach to efficiently evaluate ion-doped NASICON materials. We developed a convolutional neural network (CNN) model capable of predicting the performance of various ion-doped NASICON compounds by leveraging extensive datasets from prior experimental investigation. The model demonstrated high accuracy and efficiency in predicting ionic conductivity and electrochemical properties. Key findings include the successful synthesis and validation of three NASICON materials predicted by the model, with experimental results closely matching the model’s predictions. This research not only enhances the understanding of ion-doping effects in NASICON materials but also establishes a robust framework for material design and practical applications. It bridges the gap between theoretical predictions and experimental validations.

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In September 2022, Yemilab, a new underground laboratory, was finally completed in Jeongseon, Gangwon Province, South Korea. Situated at a depth of 1000 m, it boasts an exclusive experimental area of 3000 m². Currently, preparations are in progress for the AMoRE-II experiment, which aims to investigate neutrinoless double beta decay, as well as for the COSINE-100 upgrade (COSINE-100U), a direct dark matter detection experiment. Both experiments are scheduled to commence in the second quarter of 2024 at Yemilab. Furthermore, the facility encompasses a cylindrical pit, approximately 6300 m³ in volume, designed to serve as a multipurpose laboratory. This laboratory will facilitate next-generation experiments focusing on neutrinos, dark matter, and related areas of research. This article presents a detailed overview of Yemilab’s construction, infrastructure, and its pivotal physics programs.

The one-dimensional quantum breakdown model, which features spatially asymmetric fermionic interactions simulating the electrical breakdown phenomenon, exhibits an exponential U(1) symmetry and a variety of dynamical phases including many-body localization and quantum chaos with quantum scar states. We investigate the minimal quantum breakdown model with the minimal number of on-site fermion orbitals required for the interaction and identify a large number of local conserved charges in the model. We then reveal a mapping between the minimal quantum breakdown model in certain charge sectors and a quantum link model which simulates the U(1) lattice gauge theory and show that the local conserved charges map to the gauge symmetry generators. A special charge sector of the model further maps to the PXP model, which shows quantum many-body scars. This mapping unveils the rich dynamics in different Krylov subspaces characterized by different gauge configurations in the quantum breakdown model.

Geoacoustic exploration is a rapidly evolving field investigating underground rock formations and sediment environments through acoustic waves. In this paper, we present a review of recent research progress, focusing on newly discovered physical phenomena, such as the reflection and refraction of acoustic waves at the interface between anisotropic rocks and between liquid and solid, the characteristics of electric-acoustic (and acoustic-electric) conversion of piezoelectric transducers, the physical mechanism of acoustic wave propagation in viscous media, and the generation of intrinsic noise. We developed new physical models, introduced a parallel transmission network describing piezoelectric transducers for electric-acoustic (and acoustic-electric) energy transfer, and derived new formulations and algorithms associated with the latest model. We will discuss the potential of abnormal incidence angle, acoustic attenuation, and acoustic Goos-Hänchen effect and propose a method of inversion of formation reflection coefficient using logging and seismic data acquired from anisotropic rocks with dip angle. We will also discuss the physical mechanism and potential applications of the intrinsic noise generated inside viscous solid media. Finally, we introduce a parallel/series lumped vibrational transmission network, explain the acoustic measurement process, and discuss applications of the Kaiser effect in petroleum engineering.

Exceptional points are the branch-point singularities of non-Hermitian Hamiltonians and have rich consequences in open-system dynamics. While the exceptional points and their critical phenomena are widely studied in the non-Hermitian settings without quantum jumps, they also emerge in open quantum systems depicted by the Lindblad master equations, wherein they are identified as the degeneracies in the Liouvillian eigenspectrum. These Liouvillian exceptional points often have distinct properties compared to their counterparts in non-Hermitian Hamiltonians, leading to fundamental modifications of the steady states or the steady-state-approaching dynamics. Since the Liouvillian exceptional points widely exist in quantum systems such as the atomic vapors, superconducting qubits, and ultracold ions and atoms, they have received increasing amount of attention of late. Here, we present a brief review on an important aspect of the dynamic consequence of Liouvillian exceptional points, namely the chiral state transfer induced by the parametric encircling the Liouvillian exceptional points. Our review focuses on the theoretical description and experimental observation of the phenomena in atomic systems that are experimentally accessible. We also discuss the ongoing effort to unveil the collective dynamic phenomena close to the Liouvillian exceptional points, as a consequence of the many-body effects therein. Formally, these phenomena are the quantum-many-body counterparts to those in classical open systems with nonlinearity, but hold intriguing new potentials for quantum applications.

Perovskites are a class of semiconductors initially recognized for their exceptional efficiency in solar cell applications. Subsequent research has revealed their diverse and attractive optoelectronic properties. Over the last decades, molecule-level engineering attempts toward the original three-dimensional (“3D”) perovskites have led to the emergence of two-dimensional (“2D”) layered crystals and introduced extensive compositional, structural, and electronic tunability through the incorporation of various organic cations to form hybrid perovskite systems. Consequently, we concentrated on the theoretical investigation of innovative and complex 2D hybrid organic-inorganic perovskites using density functional theory (DFT). A DFT-based simulation protocol has been developed, enabling the efficient simulation of hybrid perovskite systems and providing accurate explanations and predictions of various experimental phenomena. This account article summarizes the recent in-depth DFT study of the structural, electronic, and spin-related properties of 2D hybrid organic-inorganic perovskites.

In generic closed quantum systems, the complexity of operators increases under time evolution governed by the Heisenberg equation, reflecting the scrambling of local quantum information. However, when systems interact with an external environment, the system-environment coupling allows operators to escape from the system, inducing a dynamical transition between the scrambling phase and the dissipative phase. This transition is known as the environment-induced information scrambling transition, originally proposed in Majorana fermion systems. In this work, we advance this discovery by investigating the transition in charge-conserved systems with space-time randomness. We construct solvable Brownian Sachdev-Ye-Kitaev models of complex fermions coupled to an environment, enabling the analytical computation of operator growth. We determine the critical dissipation strength, which is proportional to (n(1-n)) with n being the density of the complex fermions, arising from the suppression in the quantum Lyapunova exponent due to the Pauli blockade in the scattering process. We further analyze the density dependence of maximally scrambled operators at late time. Our results shed light on the intriguing interplay between information scrambling, dissipation, and conservation laws.