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1. chinaXiv:202205.00036 [pdf]


朱广宇; 向静; 周登梅; 李鹏; 欧汉文; 陈西浩
Subjects: Materials Science >> Electronic, Optical and Magnetic Materials

本文研究近紫外飞秒激光脉冲在聚甲基戊烯内部刻写的应用技术。我们发现该热塑材料具有偏振敏感性的特征。首先刻写实验使用数字孔径为0.05的透镜聚焦, 通过对超连续光谱的分析,测得稳定成丝刻写的激光脉冲功率在2.2MW - 9.2MW区间内,并由此推断该种材料的非线性折射率为n2387=2×10-16cm2W-1,推算三阶susceptibility χ(3)为    1.1×10-14esu。稳定成丝加工长度在300μm-1500μm。然后,实验使用数字孔径为0.4的组合物镜聚焦刻写厚度为~700μm,栅距为5μm的布拉格光栅。通过对光栅产品的衍射效率测试,推断最大折射率的变化为~0.01,这比文献中的记录数据,提高一个数量级。实验结果证明了激光脉冲峰值强度对于诱导非线性吸收的重要性,而双光子吸收为温和可控改性的物理机制。本工作为科研人员和光学器件设计和制作提供了最新的参考。

submitted time 2022-05-08 Hits1441Downloads46 Comment 0

2. chinaXiv:202205.00002 [pdf]

Large-scale ultra-fast strain engineering of CVD-grown two-dimensional materials on strain self-limited deformable nanostructures towards enhanced field effect transistors

Zheng Huang; Nan Lu; Zifeng Wang; Shuoheng Xu; Jie Guan; Yaowu Hu
Subjects: Physics >> Condensed Matter: Electronic Structure, Electrical, Magnetic, and Optical Properties

Strain engineering of 2D materials is capable of tuning the electrical and optical properties of the materials without introducing additional atoms. However, there are still great challenges in realizing straining of 2D materials with CMOS compatibility. Here, a method for large-scale ultrafast strain engineering of CVD-grown 2D materials is proposed. We introduce locally non-uniform strains through the cooperative deformation of materials and metal/metal oxide core/shell nanoparticles through cold laser shock. Raman and PL spectra reveal that the tensile strain of MoS2 changes and the band gap decreases after laser shock. MD simulations are used to investigate the mechanism of the ultrafast straining of CVD-grown 2D materials. Field effect transistors of CVD MoS2 were fabricated, and the performances before and after straining of the same devices are compared. By adjusting the strain level of MoS2, the field effect mobility can be increased from 1.9 cm2V-1s-1 to 44.1 cm2V-1s-1. This is the maximum value of MoS2 FETs grown by CVD with SiO2 as dielectric. As an environment-friendly, large-scale and ultra-fast manufacturing method, laser shock provides a universal strategy for large-scale adjustment of 2D materials strain, which will help to promote the manufacturing of 2D nano electronic devices and optoelectronic devices.


submitted time 2022-04-30 Hits1569Downloads169 Comment 0

3. chinaXiv:202201.00057 [pdf]

Ladderpath Approach: How Tinkering and Reuse Enhance Complexity and Information

Liu, Yu; Di, Zengru; Gerlee, Philip
Subjects: Information Science and Systems Science >> Basic Disciplines of Information Science and Systems Science

The notion of information and complexity are important concepts in many scientific fields such as molecular biology, evolutionary theory, and exobiology. Most measures of these quantities, such as Shannon entropy and related complexity measures, are only defined for objects drawn from a statistical ensemble and cannot be computed for single objects. Based on assembly theory, we attempt to fill this gap by introducing the notion of a ladderpath which describes how an object can be decomposed into a hierarchical structure using repetitive elements. From the ladderpath two measures naturally emerge: the ladderpath-index and the order-index, which represent two axes of complexity. We show how the ladderpath approach can be applied to both strings and spatial patterns and argue that all systems that undergo evolution can be described as ladderpaths. Further, we discuss possible applications to human language and the origins of life. The ladderpath approach provides a novel characterization of the information that is contained in a single object (or a system) and could aid in our understanding of evolving systems and the origin of life in particular.

submitted time 2022-04-26 Hits5364Downloads537 Comment 0

4. chinaXiv:202204.00025 [pdf]

Co-positivity of tensors and Stability conditions of two Higgs potentials

Subjects: Physics >> The Physics of Elementary Particles and Fields

We give how to calculate the vacuum stability  conditions of scalar potential for two Higgs doublet model with explicit CP conservation. Moreover, the analytical sufficient and necessary conditions are obtained. The argument methods are first used to study the tensor with two parameters.

submitted time 2022-04-02 Hits1916Downloads220 Comment 0

5. chinaXiv:202202.00008 [pdf]

非互易 Aubry-Andr\'e 模型的经典电路模拟

成恩宏 (Enhong Cheng); 郎利君 (Li-Jun Lang)
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.
Subjects: Physics >> Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics
Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology

非厄米的引入扩展了传统厄米量子系统中的概念并诱导出许多新奇的物理现象, 比如非厄米系统所独有的非厄米趋肤效应, 这使得对非厄米量子模型的模拟成为大家关注的热点. 相比于量子平台, 经典系统具有成本低廉、技术成熟、室温条件等优势, 而其中的经典电路系统则更加灵活, 原则上可以模拟任意维度、任意格点间跃迁、任意边界条件下的量子紧束缚模型, 已经成为模拟量子物态的有力平台. 本文利用经典电路通过 SPICE 成功模拟了一个重要的非厄米量子模型 —— 非互易 Aubry-Andr\'e 模型 —— 的稳态性质, 此模型同时具有非互易的格点跃迁和准周期的格点在位势. 以此为例, 详细介绍了如何建立经典电路的拉普拉辛形式与量子紧束缚模型哈密顿矩阵在不同边界条件下的映射, 尤其是如何利用电流型负阻抗变换器构建模型的非互易性. 然后, 根据电路的格林函数, 通过 AC 电流驱动并测量电压响应的方式, 用 SPICE 模拟了周期边界条件下的复能谱和相应的能谱缠绕数, 以及开边界条件下的趋肤与局域模式的竞争. 其中, 为了使电路的响应不发散, 本文还解析地给出辅助元件的设置原则. 结果显示, SPICE 模拟与理论计算很好地吻合, 为进一步的实验实现提供了详细的指导. 由于本文电路设计与测量方案的普适性, 原则上可以直接应用于其他非厄米量子模型的电路模拟. 

submitted time 2022-03-24 Hits2741Downloads380 Comment 0

6. chinaXiv:202203.00008 [pdf]

A Statistical Fields Theory underlying the Thermodynamics of Ricci Flow and Gravity

Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

The paper proposes a statistical fields theory of quantum reference

frame underlying the Perelman's analogies between his formalism of

the Ricci flow and the thermodynamics. The theory is based on a $d=4-\epsilon$

quantum non-linear sigma model (NLSM), interpreted as a quantum reference

frame system which a to-be-studied quantum system is relative to.

The statistic physics and thermodynamics of the quantum frame fields

is studied by the density matrix of them obtained by the Gaussian

approximation quantization. The induced Ricci flow of the frame fields

and the Ricci-DeTurck flow of the frame fields associated with the

density matrix is deduced. In this framework, the diffeomorphism anomaly

of the theory has deep thermodynamic interpretation. The trace anomaly

is related to a Shannon entropy in terms of the density matrix, which

monotonically flows and achieves its maximal value at the flow limit,

called the Gradient Shrinking Ricci Soliton (GSRS). A relative Shannon

entropy w.r.t. the maximal entropy gives a statistical interpretation

to Perelman's partition function, which is also monotonic and giving

an analogous H-theorem to the statistical frame fields system. We

find that a temporal static 3-space of the GSRS spacetime is in a

thermal equilibrium state, and Perelman's analogies between his formalism

and the thermodynamics of the frame fields in equilibrium can be explicitly

given in the framework. As a possible underlying microscopic theory

of the gravitational system, the theory is also applied to understand

the thermodynamics of the Schwarzschild black hole. The cosmological

constant in the effective theory of gravity at cosmic scale is also

briefly given.

submitted time 2022-03-03 Hits2369Downloads425 Comment 0

7. chinaXiv:201610.00003 [pdf]


Chen, Chiyi
Subjects: Physics >> Geophysics, Astronomy, and Astrophysics
Subjects: Astronomy >> Galaxy and Cosmology


submitted time 2022-02-04 Hits4253Downloads494 Comment 0

8. chinaXiv:202201.00124 [pdf]


Subjects: Physics >> Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics


submitted time 2022-01-29 Hits3772Downloads357 Comment 0

9. chinaXiv:202201.00098 [pdf]


Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.


submitted time 2022-01-26 Cooperative journals:《干旱区研究》 Hits2387Downloads255 Comment 0

10. chinaXiv:202201.00064 [pdf]

Determination of neutron-skin thickness using configurational information entropy

Ma, Chun-Wang ; Liu, Yi-Pu; Wei, Hui-Ling; Pu, Jie; Cheng, Kai-Xuan; Wang, Yu-Ting
Subjects: Physics >> Nuclear Physics

Configurational information entropy (CIE) theory was employed to determine the neutron skin thickness of neutron-rich calcium isotopes. The nuclear density distributions and fragment cross-sections in 350 MeV/u 40-60Ca + 9Be projectile fragmentation reactions were calculated using a modified statistical abrasion-ablation model. CIE quantities were determined from the nuclear density, isotopic, mass, and charge distributions. The linear correlations between the CIE determined using the isotopic, mass, and charge distributions and the neutron skin thickness of the projectile nucleus show that CIE provides new methods to extract the neutron skin thickness of neutron-rich nuclei.

submitted time 2022-01-21 Cooperative journals:《Nuclear Science and Techniques》 Hits3664Downloads338 Comment 0

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