On thermalization in the SYK and supersymmetric SYK models

The eigenstate thermalization hypothesis is a compelling conjecture which strives to explain the apparent thermal behavior of generic observables in closed quantum systems. Although we are far from a complete analytic understanding, quantum chaos is often seen as a strong indication that the ansatz holds true. In this paper, we address the thermalization of energy eigenstates in the Sachdev-Ye-Kitaev model, a maximally chaotic model of strongly-interacting Majorana fermions. We numerically investigate eigenstate thermalization for specific few-body operators in the original SYK model as well as its $\mathcal{N}=1$ supersymmetric extension and find evidence that these models satisfy ETH. We discuss the implications of ETH for a gravitational dual and the quantum information-theoretic properties of SYK it suggests.Comment: Published versio

Note on global symmetry and SYK model

The goal of this note is to explore the behavior of effective action in the SYK model with general continuous global symmetries. A global symmetry will decompose the whole Hamiltonian of a many-body system to several single charge sectors. For the SYK model, the effective action near the saddle point is given as the free product of the Schwarzian action part and the free action of the group element moving in the group manifold. With a detailed analysis in the free sigma model, we prove a modified version of Peter-Weyl theorem that works for generic spin structure. As a conclusion, we could make a comparison between the thermodynamics and the spectral form factors between the whole theory and the single charge sector, to make predictions on the SYK model and see how symmetry affects the chaotic behavior in certain timescales.Comment: 44 page

Note on the Green's function formalism and topological invariants

It has been discovered previously that the topological order parameter could be identified from the topological data of the Green's function, namely the (generalized) TKNN invariant in general dimensions, for both non-interacting and interacting systems. In this note, we show that this phenomenon has a clear geometric derivation. This proposal could be regarded as an alternative proof for the identification of the corresponding topological invariant and the topological order parameter

In Situ Methylation Transforms Aggregation‐Caused Quenching into Aggregation‐Induced Emission: Functional Porous Silsesquioxane‐Based Composites with Enhanced Near‐Infrared Emission

Methylation of TPA‐DCM (2‐(2,6‐bis‐4‐(diphenylamino)stryryl‐4H‐pyranylidene)malononitrile) that exhibits aggregation‐caused quenching (ACQ) results in the fluorophore M‐TPA‐DCM (2‐(2,6‐bis((E)‐4‐(di‐p‐tolylamino)‐styryl)‐4H‐pyran‐4‐ylidene]malononitrile) that shows aggregation‐induced emission (AIE) and NIR fluorescence and has a conjugated “D‐π‐A‐π‐D” electronic configuration. Friedel‐Crafts reaction of TPA‐DCM and octavinylsilsesquioxane (OVS) resulted in a family of porous materials (TPAIEs) that contain the M‐TPA‐DCM motif and show large Stokes shifts (180 nm), NIR emission (670 nm), tunable porosity (SBET from 160 to 720 m2 g−1, pore volumes of 0.13–0.55 cm3 g−1), as well as high thermal stability (400 °C, 5 % mass loss, N2). As a simple test case, one of TPAIE materials was used to sense Ru3+ ions with high selectivity and sensitivity.Small changes with big effect: Methylation of TPA‐DCM (2‐(2,6‐bis‐4‐(diphenylamino)stryryl‐4H‐pyranylidene)malononitrile), which exhibits aggregation‐caused quenching (ACQ), gives the fluorophore M‐TPA‐DCM (2‐(2,6‐bis((E)‐4‐(di‐p‐tolylamino)‐styryl)‐4H‐pyran‐4‐ylidene)malononitrile) that shows aggregation‐induced emission (AIE) and NIR fluorescence. Friedel‐Crafts reaction of TPA‐DCM with octavinylsilsesquioxane produces a family of porous composites (TPAIEs) with the M‐TPA‐DCM motif. TPAIEs show large Stokes shifts, NIR emission, tunable porosity as well as high thermal stability.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151996/1/cplu201900568_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151996/2/cplu201900568.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151996/3/cplu201900568-sup-0001-misc_information.pd

Supersymmetric SYK model and random matrix theory

In this paper, we investigate the effect of supersymmetry on the symmetry classification of random matrix theory ensembles. We mainly consider the random matrix behaviors in the N = 1 supersymmetric generalization of Sachdev-Ye-Kitaev (SYK) model, a toy model for two-dimensional quantum black hole with supersymmetric constraint. Some analytical arguments and numerical results are given to show that the statistics of the supersymmetric SYK model could be interpreted as random matrix theory ensembles, with a different eight-fold classification from the original SYK model and some new features. The time-dependent evolution of the spectral form factor is also investigated, where predictions from random matrix theory are governing the late time behavior of the chaotic hamiltonian with supersymmetry

Fast Growth of Thin MAPbI\u3csub\u3e3\u3c/sub\u3e Crystal Wafers on Aqueous Solution Surface for Efficient Lateral-Structure Perovskite Solar Cells

Solar-grade single or multiple crystalline wafers are needed in large quantities in the solar cell industry, and are generally formed by a top-down process from crystal ingots, which causes a significant waste of materials and energy during slicing, polishing, and other processing. Here, a bottom-up technique that allows the growth of wafer-size hybrid perovskite multiple crystals directly from aqueous solution is reported. Single-crystalline hybrid perovskite wafers with centimeter size are grown at the top surface of a perovskite precursor solution. As well as saving raw materials, this method provides unprecedented advantages such as easily tunable thickness and rapid growth of the crystals. These crystalline wafers show high crystallinity, broader light absorption, and a long carrier recombination lifetime, comparable with those of bulk single crystals. Lateral-structure perovskite solar cells made of these crystals demonstrate a record power conversion efficiency of 5.9%. Includes supplementary materials

An Explicit Method for Fast Monocular Depth Recovery in Corridor Environments

Monocular cameras are extensively employed in indoor robotics, but their performance is limited in visual odometry, depth estimation, and related applications due to the absence of scale information.Depth estimation refers to the process of estimating a dense depth map from the corresponding input image, existing researchers mostly address this issue through deep learning-based approaches, yet their inference speed is slow, leading to poor real-time capabilities. To tackle this challenge, we propose an explicit method for rapid monocular depth recovery specifically designed for corridor environments, leveraging the principles of nonlinear optimization. We adopt the virtual camera assumption to make full use of the prior geometric features of the scene. The depth estimation problem is transformed into an optimization problem by minimizing the geometric residual. Furthermore, a novel depth plane construction technique is introduced to categorize spatial points based on their possible depths, facilitating swift depth estimation in enclosed structural scenarios, such as corridors. We also propose a new corridor dataset, named Corr\_EH\_z, which contains images as captured by the UGV camera of a variety of corridors. An exhaustive set of experiments in different corridors reveal the efficacy of the proposed algorithm.Comment: 10 pages, 8 figures. arXiv admin note: text overlap with arXiv:2111.08600 by other author

Jiedu Tongluo granules ameliorates post-stroke depression rat model via regulating NMDAR/BDNF signaling pathway

Post-stroke depression (PSD) is one of the most common stroke complications, which seriously affects stroke’s therapeutic effect and brings great pain for patients. The pathological mechanism of PSD has not been revealed. Jiedu Tongluo granules (JDTLG) is an effective traditional Chinese medicine for PSD treatment which is widely used in clinical treatment. JDTLG has a significant therapeutic effect against PSD, but the mechanism is still unclear. The PSD rat model was established by carotid artery embolization combined with chronic sleep deprivation followed by treating with JDTLG. Neurobehavioral and neurofunctional experiments were engaged in studying the neural function of rats. Histomorphology, proteomics, and western blotting researches were performed to investigate the potential molecular mechanisms related to JDTLG therapy. Oral treatment of JDTLG could significantly improve the symptoms of neurological deficit and depression symptoms of PSD rats. Proteomic analysis identified several processes that may involve the regulation of JDTLG on the PSD animal model, including energy metabolism, nervous system, and N-methyl-D-aspartate receptor (NMDAR)/brain-derived neurotrophic factor (BDNF) signal pathway. Our results showed that JDTLG could reduce glutamate (Glu) level and increase gamma-aminobutyric acid (GABA) level via regulating the NMDAR/BDNF pathway, which may play a vital role in the occurrence and development of PSD

Molecular doping enabled scalable blading of efficient hole-transport-layer-free perovskite solar cells

The efficiencies of perovskite solar cells (PSCs) are now reaching such consistently high levels that scalable manufacturing at low cost is becoming critical. However, this remains challenging due to the expensive hole-transporting materials usually employed, and difficulties associated with the scalable deposition of other functional layers. By simplifying the device architecture, hole-transport-layer-free PSCs with improved photovoltaic performance are fabricated via a scalable doctor-blading process. Molecular doping of halide perovskite films improved the conductivity of the films and their electronic contact with the conductive substrate, resulting in a reduced series resistance. It facilitates the extraction of photoexcited holes from perovskite directly to the conductive substrate. The bladed hole-transport-layerfree PSCs showed a stabilized power conversion efficiency above 20.0%. This work represents a significant step towards the scalable, cost-effective manufacturing of PSCs with both high performance and simple fabrication processes