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1. chinaXiv:201607.00046 [pdf]

Exact Solution for Three-Dimensional Ising Model

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

Three-dimensional Ising model in zero external field is exactly solved by operator algebras, similar to the Onsager's approach in two dimensions. The partition function of the simple cubic crystal imposed by the periodic boundary condition along both $(0 1 0)$ and $(0 0 1)$ directions and the screw boundary condition along the $(1 0 0)$ direction is calculated rigorously. In the thermodynamic limit an integral replaces a sum in the formula of the partition function. A order-disorder transition in the infinite crystal occurs at a temperature $T=T_c$ determined by the condition: $\sinh\frac{2J}{k_BT_c}\sinh\frac{2(J_1+J_2)}{k_BT_c}=1$, where $(J_1 J_2 J)$ are the interaction energies in three directions, respectively. The analytical expressions for the internal energy and the specific heat are also given. It is also shown that the thermodynamic properties of 3D Ising model with $J_1=J_2$ are connected to those in 2D Ising model with the interaction energies $(J_1 J_{2D})$ by the relation $(\frac{J_{2D}}{k_BT})^*=(\frac{J}{k_BT})^*-\frac{J_1}{k_BT}$, where $x^*=\frac{1}{2}{\rm ln coth} x={\rm tanh}^{-1}(e^{-2x})$.

submitted time 2019-09-12 Hits4677, Downloads1245, Comment 0

2. chinaXiv:201909.00120 [pdf]

西宁盆地4种草本和灌木植物降盐效应试验研究

李淑霞; 刘亚斌; 钟鹏; 余冬梅; 胡夏嵩; 杨幼清
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

因为西宁盆地长岭沟流域自建试验区为研究区,罗出适宜当地气候条件下生长的2种灌木植物柠条锦鸡儿(Caragana korshinskii Kom.)、霸王〔Zygophyllum xanthoxylon (Bunge) Maxim.〕和2种草本植物细茎冰草(Agropyron trachycaulum cv. Slender)、紫花苜蓿(Medicago sativa Linn.)作为试验供试种,在试验区对4种植物采用单一种植和整合种植方式,探索2种种植条件下植物根系在边坡地表以下垂直方向土体中K+、Ca2+、Na+、Mg2+、SO42-、Cl-、HCO3-、CO32-相当8种易溶盐离子含量及其变化特征,评论了区内2种草本和2种灌木植物降低边坡土体盐分的能力。结果表明:单纯种植细茎冰草、紫花苜蓿、柠条锦鸡儿、霸王对边坡土体中SO42-、Ca2+、Na+有明显降低作用,草本与灌木组合Ⅰ(柠条锦鸡儿+紫花苜蓿+仔细茎冰草组合)和草本与灌木组合Ⅱ(霸王+紫花苜蓿+仔细茎冰草组合)针对边坡土体中SO42、Ca2+、Mg2+、K+、Na+表现有明显降低作用;紫花苜蓿的下降盐效果相对比较为显著、其次为柠条锦鸡儿和密切茎冰草,霸王的下降盐效果不及前者显著;草本与灌木组合Ⅱ的下降盐效果相对显著于草本与灌木组合Ⅰ。

submitted time 2019-09-09 From cooperative journals:《干旱区研究》 Hits1691, Downloads38, Comment 0

3. chinaXiv:201907.00026 [pdf]

Exact Solution of Quantum Rabi Model

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

Quantum Rabi model is exactly solved by employing the parameter-dependent unitary transformation method in the Bargmann space. The complete energy spectrum consists of two double-fold sub-energy spectra. The eigenvalue is determined by the parameter in the unitary transformation, which satisfies a highly nonlinear equation. Such the energy spectrum completely coincides with that obtained in the occupation number representation [D. Zhang, chinaXiv:201708.00168].

submitted time 2019-07-31 Hits1332, Downloads74, Comment 0

4. chinaXiv:201907.00002 [pdf]

The Change of the Electron Clouds of Ions in Cuprate Superconductor CaCuO2: A First-Principles Investigation of the Electron-Pairing

Tiege Zhou
Subjects: Physics >> Condensed Matter: Electronic Structure, Electrical, Magnetic, and Optical Properties

P. W. Anderson raised an important question in 2007: Is There Glue in Cuprate Superconductors? The author believes that the change of the electron clouds of ions is the glue in cuprate superconductors. The change of the electron clouds of the ions in the parent structure of the layered high-temperature superconductors CaCuO2 has been studied by the first-principles calculations. The electron clouds of Cu2+ and O2- ions change obviously under electric fields. It is also found, for the first time, the characteristic frequencies of the change of the electron clouds are 250 meV, 360 meV, and 100 meV, respectively, for the modes observed. The frequencies are low and close to that of lattice vibrations, indicating the change of the electron cloud of ions can be the electron-pairing medium in cuprate superconductors.

submitted time 2019-07-02 Hits302, Downloads125, Comment 0

5. chinaXiv:201906.00024 [pdf]

Characteristic frequency of the orbital fluctuation in the unconventional iron-based superconductor BaFe2As2: A TDDFT investigation of the electron pairing mechanism

Tiege Zhou
Subjects: Physics >> Condensed Matter: Electronic Structure, Electrical, Magnetic, and Optical Properties

It is proposed that the electron-pairing medium of the iron-based superconductors may be the orbital fluctuation of the transition metal ions. But the characteristic frequency of the orbital fluctuation has not been given. For the first time, the author has calculated the real-time evolution of the electron clouds of transition metal ions in BaFe2As2 under excitations by the time-dependent density functional theory (TDDFT). There are different modes of fluctuations. The characteristic frequencies are 150 meV, 160 meV, 250 meV, and 200 meV, respectively, for the modes the author observed. The results are unexpected, because the general view is that the change of the electron density is very quick, and the frequency is much higher than the lattice vibration. The frequencies the author obtained are close to that of the lattice vibration in conventional superconductors at normal and high pressures, indicating the orbital (or electron cloud) fluctuation can by the electron pairing medium. Based on the calculation results, the author proposed a new electron pairing mechanism.

submitted time 2019-06-13 Hits299, Downloads146, Comment 0

6. chinaXiv:201905.00050 [pdf]

根据单极感应问题的多极感应实验

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

针对单极感应之谜,本文注意到磁力线是闭合线,使用洛伦茨力概念首先证明N和M少种相对观点都能够成立解释自法拉第时期以来典型的、发生较大影响的单极感应实验。连使用等效电路和比较显著的方法推演出单极感应实验测量回路中影响电动势的相似表达式,证明单极感应问题至今未果的原因是实验采用的轴对称磁体外围磁场特殊的对称性分布布局,还分布布局不按照磁体旋转而改变造成的。啊证明单极感应实验本身无法解决单极感应问题。介绍了同种多极感应实验方案和尝试结果,结合实验磁体外围磁场分布状况,同用N和M少种看法对照分析了实验结果,查获了法拉第和韦伯当初的单极感应实验测量回路中的感应电动势是由于磁体外相对于实验室参照系静止的线产生的结论,该结论与M观的结论一致。

submitted time 2019-05-08 Hits2955, Downloads226, Comment 0

7. chinaXiv:201904.00095 [pdf]

Real-Time Evolution of the Electron Clouds of Transition Metal Ions: Electron-Pairing Medium of Unconventional High Temperature Superconductors

Tege Zhou
Subjects: Physics >> Condensed Matter: Electronic Structure, Electrical, Magnetic, and Optical Properties

The electron-pairing mechanism in unconventional high temperature superconductors (HTS) has not been resolved. The author proposed that the electron-pairing medium of unconventional HTS is the change of the electron clouds of transition metal ions, which is analogous to the lattice vibration in conventional superconductors. Real-time evolution of the electron clouds of transition metal ions under excitations in La2Fe2As2O2, FeSe sheet, Fe2KSe2, CaCuO2, and HgBa2Ca2Cu3O8 was calculated by the time-dependent density functional theory (TDDFT). The characteristic frequency is about 90-250 meV, which is equivalent to the lattice vibration frequencies, showing that the change of the electron clouds of the transition metal ions can be the electron-pairing medium in unconventional HTS.

submitted time 2019-04-24 Hits913, Downloads251, Comment 0

8. chinaXiv:201802.00685 [pdf]

An Explanation of the Interactions between Waves and Electrons: Discussion of Electromagnetic Fields

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

The interactions between waves and electrons are the basis of vacuum tubes and particle accelerators. In order to further understand the interactions, we proposed a new electromagnetic model. In this model, the photon is composed of two elementary particles – ephoton and mphoton, which are the basic particles that form the electric fields and magnetic fields, respectively. There are many ephotons around the electrons and the electrons can absorb the ephotons. The proposed electromagnetic model can well explain the electromagetic phenomena and the interactions between waves and electrons.

submitted time 2019-04-12 Hits3225, Downloads1137, Comment 0

9. chinaXiv:201905.00054 [pdf]

多体多自由度量子隐形传态的张量表示

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

[目的] 找到一种最广泛情况下量子隐形传态的相似表示与代数结构。 [办法] 归纳推理与演绎推理,使用多项式相乘与张量积中的当性发现一般原理。 [结果] 以多体单自由度或单体多自由度的量子隐形传态推广至多体多自由度,和混合态。 [局限] 无法推广到连续谱量子态。 [结论] 预言多体多自由度单次量子隐形传态的存在,连包含了已经被实验证明的有特殊情况。

submitted time 2019-04-11 Hits4339, Downloads227, Comment 0

10. chinaXiv:201905.00053 [pdf]

纠缠态判据与高阶张量可分性的充分必要条件

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

[目的] 找到高阶张量和纯态可写成多只低阶张量乘积的充要条件。 [办法] 举一反三推理、归纳推理,从多头函数可分离变量的充要条件出发,使用和矩阵的代数余子仪的性质,末了取得一般的结论。 [结果] 证明定理及那个多只等价形式。 [局限] 不适用于混合态。 [结论] 纯态是否是纠缠态的充要条件。

submitted time 2019-04-11 Hits4056, Downloads194, Comment 0

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