AAPPS Bulletin最新文献

The National Array of Neutron Detectors (NAND) at IUAC is one of the big detector arrays used in experiments to study nuclear fission through the measurement of the neutrons emitted during the process. The array is installed at IUAC heavy ion accelerator facility. NAND consists of 100 liquid scintillators mounted on a semi-spherical geometry covering a total of 3.3(%) of 4(pi) solid angle. The 175-cm-long flight path provides good energy resolution of the emitted neutrons, enabling precise measurement of neutron multiplicity for very heavy nuclei. The fission fragment time-of-flight spectrometer coupled with large array of neutron detectors makes it a versatile tool for exploring the properties of nuclear fission using heavy ions from IUAC accelerators. Over the past two decades, several experiments were performed using NAND facility providing valuable information on traditional fission research extending to new mass region. This article reviews overall details of NAND facility and highlights some important research activities carried out at IUAC. The future research possibilities are also discussed.

Non-equilibrium dynamics have become a central research focus, exemplified by the counterintuitive Mpemba effect where initially hotter systems can cool faster than colder ones. Studied extensively in both classical and quantum regimes, this phenomenon reveals diverse and complex behaviors across different systems. This review provides a concise overview of the quantum Mpemba effect (QME), specifically emphasizing its connection to symmetry breaking and restoration in closed quantum many-body systems. We begin by outlining the classical Mpemba effect and its quantum counterparts, summarizing key findings. Subsequently, we introduce entanglement asymmetry and charge variance as key metrics for probing the QME from symmetry perspectives. Leveraging these tools, we analyze the early- and late-time dynamics of these quantities under Hamiltonian evolution and random unitary circuits. We conclude by discussing significant challenges and promising avenues for future research.

The study of strongly correlated electron systems remains a fundamental challenge in condensed matter physics, particularly in two-dimensional (2D) systems hosting various exotic phases of matter including quantum spin liquids, unconventional superconductivity, and topological orders. Although Density Matrix Renormalization Group (DMRG) has established itself as a pillar for simulating one-dimensional quantum systems, its application to 2D systems has long been hindered by the notorious “local minimum” issues. Recent methodological breakthroughs have addressed this challenge by incorporating Gutzwiller-projected wave functions as initial states for DMRG simulations. This hybrid approach, referred to as DMRG guided by Gutzwiller-projected wave functions (or Gutzwiller-guided DMRG), has demonstrated remarkable improvements in accuracy, efficiency, and the ability to explore exotic quantum phases such as topological orders. This review examines the theoretical underpinnings of this approach, details key algorithmic developments, and showcases its applications in recent studies of 2D quantum systems.

As two-dimensional (2D) semiconductor devices demand ever higher performance and tunable photo-energy responses, the ability to probe and control exciton-trion interconversion has attracted much attention. However, conventional optical studies predominantly rely on far-field schemes, which suffer from inherent limitations, such as low spatial resolution and weak photoluminescence signals, restricting practical applications. To address these challenges, plasmonic structures have been employed to enhance local electromagnetic fields, facilitating more efficient exciton-trion interconversion in 2D transition metal dichalcogenides. Furthermore, tip-enhanced approaches have expanded the frontiers of excitontrion study by enabling nanoscale spatial resolution and various modulation capabilities, under active cavity configuration. This review article addresses the critical challenge of probing and controlling exciton-trion interconversion. It provides a comprehensive overview of current techniques, spanning far field spectroscopy, plasmonic enhancement, and tip based methodologies, including both foundational strategies and emerging advanced modulation schemes. By summarizing recent developments in this field, this work aims to outline future directions for harnessing photonic quasi particles to advance next-generation optoelectronic and quantum technologies.

Precision measurements and reliable predictions of nuclear masses are pivotal in advancing nuclear physics and astrophysics. In this paper, we review recent progress in constructing a microscopic nuclear mass table based on the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) that simultaneously incorporates deformation and continuum effects. We present the predictive power and accuracy of the DRHBc mass table, highlighting its diverse applications and extensions. We then introduce the refinement of nuclear mass predictions from the relativistic continuum Hartree-Bogoliubov theory through the kernel ridge regression (KRR) machine learning approach, examining the physical effects encoded in the KRR corrections and the extrapolation distance with reasonable predictions. Finally, we offer a perspective on future improvements to the DRHBc mass table and the continued advancement of nuclear mass predictions.

The quest to unravel the intricacies of high-Tc superconductivity and strongly correlated electrons in cuprates has spurred a novel focus on direct probing of the CuO₂ planes through scanning tunneling microscopy. Infinite-layer (IL) cuprates, featuring a CuO₂-terminated surface, emerge as optimal systems for this investigation. Leveraging controllable growth via molecular beam epitaxy, both electron- and hole-doped IL cuprates are realized, with surface structure and c-axis length serving as distinctive markers. A consistent pattern in the Mott transition is established, revealing that doping merely shifts the Fermi level without inducing changes in the Mott band structure, thereby suggesting a self-modulation doping scenario. Furthermore, the identification of a nodeless superconducting gap in the CuO₂ planes challenges conventional notions derived from charge reservoir layers, advocating for a quantum well interpretation of cuprate superconductivity. This review sheds light on the distinct roles played by CuO₂ layers and charge reservoir layers, promising a more profound comprehension of cuprate superconductivity through the lens of the CuO₂ surface.