We study two simple mathematical models of an epidemic. First, we study the repetitive infection spreading in a simplified susceptible–infected–recovered–susceptible (SIRS) model including the effect of the decay of the acquired immunity. The model is an intermediate of the SIRS model including the recruitment and death terms and the SIR model in which the recovered population is assumed to be never infected again. When the decay rate δ of the acquired immunity is sufficiently low, multiple infection spreading occurs in spikes. The model equation can be reduced to a map when the decay rate δ is sufficiently low, and the spike-like multiple infection spreading is reproduced in the mapping. The period-doubling bifurcation and chaos are found in the simplified SIRS model with seasonal variations. The nonlinear phenomena are reproduced using the map. Next, we study coupled SIRS equations for the directed evolution where the mutation is expressed with a diffusion-type term. A type of reaction–diffusion equation is derived by the continuum approximation for the infected population I. The reaction–diffusion equation with the linear dependence of infection rate on the type space has an exact Gaussian solution with a time-dependent average and variance. The propagation of the Gaussian pulse corresponds to the successive transitions of the dominant variant.
我们研究了两种简单的流行病数学模型。首先，我们研究了简化的易感-感染-恢复-易感（SIRS）模型中的重复感染传播，包括获得性免疫衰减的影响。该模型是包括招募和死亡项的 SIRS 模型和假设康复人群不再受感染的 SIR 模型的中间产物。当获得性免疫的衰减率δ足够低时，多重感染传播会以尖峰形式出现。当衰减率δ足够低时，模型方程可简化为一个映射，在映射中再现了尖峰状的多重感染扩散。在具有季节变化的简化 SIRS 模型中发现了周期加倍分岔和混沌现象。非线性现象通过映射得以重现。接下来，我们研究了定向演化的 SIRS 耦合方程，其中突变用扩散型项表示。感染率与类型空间线性相关的反应扩散方程有一个精确的高斯解，其平均值和方差随时间变化。高斯脉冲的传播与主导变体的连续转变相对应。
{"title":"Repetitive Infection Spreading and Directed Evolution in the Susceptible–Infected–Recovered–Susceptible Model","authors":"Hidetsugu Sakaguchi, Keito Yamasaki","doi":"10.7566/jpsj.93.054801","DOIUrl":"https://doi.org/10.7566/jpsj.93.054801","url":null,"abstract":"We study two simple mathematical models of an epidemic. First, we study the repetitive infection spreading in a simplified susceptible–infected–recovered–susceptible (SIRS) model including the effect of the decay of the acquired immunity. The model is an intermediate of the SIRS model including the recruitment and death terms and the SIR model in which the recovered population is assumed to be never infected again. When the decay rate <i>δ</i> of the acquired immunity is sufficiently low, multiple infection spreading occurs in spikes. The model equation can be reduced to a map when the decay rate <i>δ</i> is sufficiently low, and the spike-like multiple infection spreading is reproduced in the mapping. The period-doubling bifurcation and chaos are found in the simplified SIRS model with seasonal variations. The nonlinear phenomena are reproduced using the map. Next, we study coupled SIRS equations for the directed evolution where the mutation is expressed with a diffusion-type term. A type of reaction–diffusion equation is derived by the continuum approximation for the infected population <i>I</i>. The reaction–diffusion equation with the linear dependence of infection rate on the type space has an exact Gaussian solution with a time-dependent average and variance. The propagation of the Gaussian pulse corresponds to the successive transitions of the dominant variant.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"31 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140576412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Muhammad Waseem, Irfan Mahmood, Hira Sohail, Ejaz Hussain, Hosam O. Elansary
In this article, we present a quantum Painlevé second Lax pair that explicitly involves the Planck constant ħ and an arbitrary field variable v which distinguish it from the existing Flaschka–Newell Painlevé second Lax pair. We show that Flaschka–Newell pair appears as a special case of our quantum Painlevé second Lax pair. It is shown that the compatibility of quantum Painlevé second Lax pair simultaneously yields a quantum Painlevé equation and a quantum commutation relation between field variable v and independent variable z. We also show that the field variable v with different choices yields various analogs of classical Painlevé second equation as matrix Painlevé second equation, derivative matrix Painlevé second equation, and noncommutative Painlevé second equation. Further, we construct the gauge equivalence of quantum Painlevé second Lax pair whose compatibility condition generates a quantum P34 equation involving ħ with power +1 that brings the classical P34 equation close to its quantum analogs as compared to the existing one which carries ħ with power +2.
在这篇文章中，我们提出了一种量子 Painlevé 第二拉克斯对，它明确涉及普朗克常数 ħ 和任意场变量 v，这使它有别于现有的 Flaschka-Newell Painlevé 第二拉克斯对。我们证明，Flaschka-Newell 对是我们的量子 Painlevé 第二拉克斯对的一个特例。量子 Painlevé 第二拉克斯对的兼容性同时产生了量子 Painlevé 方程以及场变量 v 和自变量 z 之间的量子换向关系。我们还表明，场变量 v 的不同选择产生了经典 Painlevé 第二方程的各种类似方程，如矩阵 Painlevé 第二方程、导数矩阵 Painlevé 第二方程和非交换 Painlevé 第二方程。此外，我们还构建了量子 Painlevé second Lax 对的量规等价性，其相容性条件产生了一个涉及ħ的量子 P34 方程，与现有的携带ħ的幂+2 方程相比，它使经典 P34 方程接近于其量子类似物。
{"title":"Quantum Painlevé Second Lax Pair and Quantum (Matrix) Analogues of Classical Painlevé II Equation","authors":"Muhammad Waseem, Irfan Mahmood, Hira Sohail, Ejaz Hussain, Hosam O. Elansary","doi":"10.7566/jpsj.93.054001","DOIUrl":"https://doi.org/10.7566/jpsj.93.054001","url":null,"abstract":"In this article, we present a quantum Painlevé second Lax pair that explicitly involves the Planck constant <i>ħ</i> and an arbitrary field variable <i>v</i> which distinguish it from the existing Flaschka–Newell Painlevé second Lax pair. We show that Flaschka–Newell pair appears as a special case of our quantum Painlevé second Lax pair. It is shown that the compatibility of quantum Painlevé second Lax pair simultaneously yields a quantum Painlevé equation and a quantum commutation relation between field variable <i>v</i> and independent variable <i>z</i>. We also show that the field variable <i>v</i> with different choices yields various analogs of classical Painlevé second equation as matrix Painlevé second equation, derivative matrix Painlevé second equation, and noncommutative Painlevé second equation. Further, we construct the gauge equivalence of quantum Painlevé second Lax pair whose compatibility condition generates a quantum P34 equation involving <i>ħ</i> with power +1 that brings the classical P34 equation close to its quantum analogs as compared to the existing one which carries <i>ħ</i> with power +2.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"62 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140589315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
During the noisy intermediate-scale quantum (NISQ) era, it is important to optimize the quantum circuits in circuit depth and gate count, especially entanglement gates, including the CNOT gate. Among all the unitary operators, diagonal unitary matrices form a special class that plays a crucial role in many quantum algorithms/subroutines. Based on a natural gate set ({ text{CNOT},R_{z}} ), quantum circuits for general diagonal unitary matrices were discussed in several previous works, and an optimal synthesis algorithm was proposed in terms of circuit depth. In this paper, we are interested in the implementation of diagonal unitary matrices with reflection symmetry, which has promising applications, including the realization of real-time evolution for first quantized Hamiltonians by quantum circuits. Owing to such a symmetric property, we show that the quantum circuit in the existing work can be further simplified and propose a constructive algorithm that optimizes the entanglement gate count. Compared to the previous synthesis methods for general diagonal unitary matrices, the quantum circuit by our proposed algorithm achieves nearly half the reduction in both the gate count and circuit depth.
{"title":"Optimized Synthesis of Circuits for Diagonal Unitary Matrices with Reflection Symmetry","authors":"Xinchi Huang, Taichi Kosugi, Hirofumi Nishi, Yu-ichiro Matsushita","doi":"10.7566/jpsj.93.054002","DOIUrl":"https://doi.org/10.7566/jpsj.93.054002","url":null,"abstract":"During the noisy intermediate-scale quantum (NISQ) era, it is important to optimize the quantum circuits in circuit depth and gate count, especially entanglement gates, including the CNOT gate. Among all the unitary operators, diagonal unitary matrices form a special class that plays a crucial role in many quantum algorithms/subroutines. Based on a natural gate set <tex-math space=\"preserve\" version=\"MathJax\">({ text{CNOT},R_{z}} )</tex-math>, quantum circuits for general diagonal unitary matrices were discussed in several previous works, and an optimal synthesis algorithm was proposed in terms of circuit depth. In this paper, we are interested in the implementation of diagonal unitary matrices with reflection symmetry, which has promising applications, including the realization of real-time evolution for first quantized Hamiltonians by quantum circuits. Owing to such a symmetric property, we show that the quantum circuit in the existing work can be further simplified and propose a constructive algorithm that optimizes the entanglement gate count. Compared to the previous synthesis methods for general diagonal unitary matrices, the quantum circuit by our proposed algorithm achieves nearly half the reduction in both the gate count and circuit depth.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"89 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140576439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To investigate the effect of the magnitude of deformations on heavy-ion fusion reactions, we have considered reactions in such a way that the deformations of the target varied whereas that of the projectile remained the same. Using an advanced statistical model, we investigated fusion reactions of 4He+233–238U, 48Ca+204–208Pb, and 48Ca+240–244Pu. The influence of quadrupole and hexadecapole deformations on Coulomb potential was considered. The fusion cross-sections and evaporation residue cross-sections studied were in good accord with that of the experiments. As a consequence, a thorough examination of fusion processes like He+U, Ca+Pb, and Ca+Pu demonstrates how quadrupole deformation simultaneously increases fusion and evaporation cross-sections. σER decreases with increasing hexadecapole deformation. Also, to comprehend the many facets of heavy-ion interactions of quadrupole and hexadecapole deformations of target nuclei, substantial deformation research in both theoretical and practical aspects is required.
{"title":"Effect of Quadrupole and Hexadecapole Deformations of Target on Projectile","authors":"Narayanaswamy Manjunatha, Holaly Chandrashekara Shastry Manjunatha, Nagaraj Sowmya, Krishnachari Nagarathnamma Sridhar, Padhmaghatta Somashekaraih Prabhavathi","doi":"10.7566/jpsj.93.054201","DOIUrl":"https://doi.org/10.7566/jpsj.93.054201","url":null,"abstract":"To investigate the effect of the magnitude of deformations on heavy-ion fusion reactions, we have considered reactions in such a way that the deformations of the target varied whereas that of the projectile remained the same. Using an advanced statistical model, we investigated fusion reactions of <sup>4</sup>He+<sup>233–238</sup>U, <sup>48</sup>Ca+<sup>204–208</sup>Pb, and <sup>48</sup>Ca+<sup>240–244</sup>Pu. The influence of quadrupole and hexadecapole deformations on Coulomb potential was considered. The fusion cross-sections and evaporation residue cross-sections studied were in good accord with that of the experiments. As a consequence, a thorough examination of fusion processes like He+U, Ca+Pb, and Ca+Pu demonstrates how quadrupole deformation simultaneously increases fusion and evaporation cross-sections. <i>σ<sub>ER</sub></i> decreases with increasing hexadecapole deformation. Also, to comprehend the many facets of heavy-ion interactions of quadrupole and hexadecapole deformations of target nuclei, substantial deformation research in both theoretical and practical aspects is required.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"31 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140576299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Seebeck coefficient is examined for two-dimensional Dirac electrons in the three-quarter filled organic conductor α-(BEDT-TTF)2I3 [BEDT-TTF denotes bis(ethylenedithio)tetrathiafulvalene] under hydrostatic pressure, where the Seebeck coefficient S is proportional to the ratio of the thermoelectric conductivity L12 to the electrical conductivity L11, i.e., S = L12/TL11 with T being the temperature. We present an improved tight-binding model in two dimensions with transfer energies determined from first-principles density functional theory calculations with an experimentally determined crystal structure. The T dependence of the Seebeck coefficient is calculated by adding impurity and electron–phonon scatterings. Noting a zero-gap state due to the Dirac cone, which results in a competition from contributions between the conduction and valence bands, we show positive Sx and Sy at finite temperatures and analyze them in terms of spectral conductivity. The relevance of the calculated Sx (perpendicular to the molecular stacking axis) to the experiment is discussed.
我们研究了静水压力下四分之三填充有机导体 α-(BEDT-TTF)2I3 [BEDT-TTF 表示双(亚乙二硫基)四硫代富勒烯] 中二维狄拉克电子的塞贝克系数，其中塞贝克系数 S 与热电导率 L12 与电导率 L11 之比成正比，即 S = L12/TL11，T 为温度。我们提出了一种改进的二维紧密结合模型，其传递能量是通过第一原理密度泛函理论计算和实验确定的晶体结构确定的。通过添加杂质和电子-声子散射，计算出了塞贝克系数的 T 依赖性。我们注意到由于狄拉克锥的存在，导带和价带之间的贡献会产生竞争，从而导致零间隙状态，因此我们在有限温度下显示出正的 Sx 和 Sy，并从光谱电导率的角度对它们进行了分析。我们还讨论了计算出的 Sx（垂直于分子堆积轴）与实验的相关性。
{"title":"Seebeck Effect of Dirac Electrons in Organic Conductors under Hydrostatic Pressure Using a Tight-Binding Model Derived from First Principles","authors":"Yoshikazu Suzumura, Takao Tsumuraya, Masao Ogata","doi":"10.7566/jpsj.93.054704","DOIUrl":"https://doi.org/10.7566/jpsj.93.054704","url":null,"abstract":"The Seebeck coefficient is examined for two-dimensional Dirac electrons in the three-quarter filled organic conductor <i>α</i>-(BEDT-TTF)<sub>2</sub>I<sub>3</sub> [BEDT-TTF denotes bis(ethylenedithio)tetrathiafulvalene] under hydrostatic pressure, where the Seebeck coefficient <i>S</i> is proportional to the ratio of the thermoelectric conductivity <i>L</i><sub>12</sub> to the electrical conductivity <i>L</i><sub>11</sub>, i.e., <i>S</i> = <i>L</i><sub>12</sub>/<i>TL</i><sub>11</sub> with <i>T</i> being the temperature. We present an improved tight-binding model in two dimensions with transfer energies determined from first-principles density functional theory calculations with an experimentally determined crystal structure. The <i>T</i> dependence of the Seebeck coefficient is calculated by adding impurity and electron–phonon scatterings. Noting a zero-gap state due to the Dirac cone, which results in a competition from contributions between the conduction and valence bands, we show positive <i>S<sub>x</sub></i> and <i>S<sub>y</sub></i> at finite temperatures and analyze them in terms of spectral conductivity. The relevance of the calculated <i>S<sub>x</sub></i> (perpendicular to the molecular stacking axis) to the experiment is discussed.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"67 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140588767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Magnetic phase diagram for the Hubbard model on the β-Mn type lattice has been calculated as a function of the Coulomb interaction energy parameter U and the electron number per atom n by using the generalized Hartree–Fock approximation combined with the recursion method for electronic-structure calculations. The ferromagnetic state, the ferrimagnetic state, and the helimagnetic state as well as the 3Q multiple spin density waves (3QMSDW) states have been obtained on the U–n plane. Their detailed structures are examined with use of the Fourier analysis. It is shown that the calculated phase diagram and the Dzyaloshinskii–Moriya interaction elucidate the magnetic interactions for the itinerant-electron skyrmions in transition metal alloys and compounds on the β-Mn type lattice.
{"title":"Magnetic Phase Diagram and Skyrmions of the Hubbard Model on the β-Mn Type Lattice","authors":"Yoshiro Kakehashi","doi":"10.7566/jpsj.93.054702","DOIUrl":"https://doi.org/10.7566/jpsj.93.054702","url":null,"abstract":"Magnetic phase diagram for the Hubbard model on the <i>β</i>-Mn type lattice has been calculated as a function of the Coulomb interaction energy parameter <i>U</i> and the electron number per atom <i>n</i> by using the generalized Hartree–Fock approximation combined with the recursion method for electronic-structure calculations. The ferromagnetic state, the ferrimagnetic state, and the helimagnetic state as well as the 3<i>Q</i> multiple spin density waves (3QMSDW) states have been obtained on the <i>U</i>–<i>n</i> plane. Their detailed structures are examined with use of the Fourier analysis. It is shown that the calculated phase diagram and the Dzyaloshinskii–Moriya interaction elucidate the magnetic interactions for the itinerant-electron skyrmions in transition metal alloys and compounds on the <i>β</i>-Mn type lattice.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"59 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140588931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It has been more than 40 years since superconductivity was discovered in organic conductors, and the way scientists view organic superconductors has changed over time. First, the fact that organic conductors exhibit superconductivity was a novelty in itself, and subsequently, it was shown that behind the superconductivity is the physics of electron correlation, which has been a focus in condensed matter physics at large. Amid the marked development of correlation physics, the unique characteristics of organic conductors, e.g., a variety of lattice geometries and the highly compressible feature, led to the elucidation of fundamental principles and the finding of new phenomena, such as bandwidth-controlled Mott transitions and possible quantum spin liquids. However, most organic superconductors have commensurate band fillings, such as one-half or one-quarter, whereas inorganic superconductors, such as high-Tc cuprates and iron-based superconductors, have often been investigated under the variation of their band fillings. Thus, the physical linkage between organic and inorganic superconductors has remained unresolved. In this review article, we focus on the layered nonstoichiometric superconductor, κ-(BEDT-TTF)4Hg2.89Br8, which is exceptional among organic conductors in that the nonstoichiometry serves as doping to a half-filled band. Moreover, the strong correlation of electrons and a geometrically frustrated triangular lattice make this system exhibit the unique phenomena involved in Mottness, spin liquidity, and superconductivity, which are key concepts of correlated electron physics. This review will summarize what we learned from the pressure study of κ-(BEDT-TTF)4Hg2.89Br8 and how these findings relate to the extensively studied issues in inorganic materials.
{"title":"Mottness and Spin Liquidity in a Doped Organic Superconductor κ-(BEDT-TTF)4Hg2.89Br8","authors":"Hiroshi Oike, Hiromi Taniguchi, Kazuya Miyagawa, Kazushi Kanoda","doi":"10.7566/jpsj.93.042001","DOIUrl":"https://doi.org/10.7566/jpsj.93.042001","url":null,"abstract":"It has been more than 40 years since superconductivity was discovered in organic conductors, and the way scientists view organic superconductors has changed over time. First, the fact that organic conductors exhibit superconductivity was a novelty in itself, and subsequently, it was shown that behind the superconductivity is the physics of electron correlation, which has been a focus in condensed matter physics at large. Amid the marked development of correlation physics, the unique characteristics of organic conductors, e.g., a variety of lattice geometries and the highly compressible feature, led to the elucidation of fundamental principles and the finding of new phenomena, such as bandwidth-controlled Mott transitions and possible quantum spin liquids. However, most organic superconductors have commensurate band fillings, such as one-half or one-quarter, whereas inorganic superconductors, such as high-<i>T</i><sub>c</sub> cuprates and iron-based superconductors, have often been investigated under the variation of their band fillings. Thus, the physical linkage between organic and inorganic superconductors has remained unresolved. In this review article, we focus on the layered nonstoichiometric superconductor, <i>κ</i>-(BEDT-TTF)<sub>4</sub>Hg<sub>2.89</sub>Br<sub>8</sub>, which is exceptional among organic conductors in that the nonstoichiometry serves as doping to a half-filled band. Moreover, the strong correlation of electrons and a geometrically frustrated triangular lattice make this system exhibit the unique phenomena involved in Mottness, spin liquidity, and superconductivity, which are key concepts of correlated electron physics. This review will summarize what we learned from the pressure study of <i>κ</i>-(BEDT-TTF)<sub>4</sub>Hg<sub>2.89</sub>Br<sub>8</sub> and how these findings relate to the extensively studied issues in inorganic materials.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140312223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have theoretically investigated the character of entanglement between photoelectrons and emitted X-ray photons in XEPECS process which is a coincidence spectroscopy of photoelectrons and emitted X-ray photons. In the calculations, we used a three-electron sp-model consisting of an inner-shell 1s orbital and an outer-shell 2p orbital. We found that entanglement occurs between spin of photoelectrons and linear polarization of emitted X-ray photons, using the wavefunction of the whole system including the photon as well as the electron system. Furthermore, we calculated the degree of entanglement and found that it shows maximum at a particular angle of emitted X-ray photon.
我们从理论上研究了 XEPECS 过程中光电子与发射的 X 射线光子之间的纠缠特性。在计算中，我们使用了由内壳 1s 轨道和外壳 2p 轨道组成的三电子 sp 模型。利用包括光子和电子系统在内的整个系统的波函数，我们发现光电子的自旋和发射的 X 射线光子的线偏振之间存在纠缠。此外，我们还计算了纠缠程度，发现在发射 X 射线光子的特定角度，纠缠程度最大。
{"title":"Theory of Simultaneous Observation of Photoelectron and Emitted X-ray Photon in X-ray Emission Spectroscopy and Their Entanglement","authors":"Ryo B. Tanaka, Takayuki Uozumi","doi":"10.7566/jpsj.93.044401","DOIUrl":"https://doi.org/10.7566/jpsj.93.044401","url":null,"abstract":"We have theoretically investigated the character of entanglement between photoelectrons and emitted X-ray photons in XEPECS process which is a coincidence spectroscopy of photoelectrons and emitted X-ray photons. In the calculations, we used a three-electron <i>sp</i>-model consisting of an inner-shell 1<i>s</i> orbital and an outer-shell 2<i>p</i> orbital. We found that entanglement occurs between spin of photoelectrons and linear polarization of emitted X-ray photons, using the wavefunction of the whole system including the photon as well as the electron system. Furthermore, we calculated the degree of entanglement and found that it shows maximum at a particular angle of emitted X-ray photon.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"100 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140312073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We studied in detail the electrical and magnetic properties of the Eu-divalent antiferromagnet EuTe2 with a tetragonal crystal structure using single crystals grown by the Te self-flux method. The observed anisotropic magnetization curves in the antiferromagnetic state below TN = 11.1 K can be understood in terms of the magnetization processes of the two-sublattice model of an antiferromagnet with uniaxial magnetic anisotropy. A characteristic feature of this compound is that it becomes an insulator with decreasing temperature at zero magnetic field, but changes to a metal with a relatively low number of carriers in magnetic fields. From the results of magnetization, magnetoresistance, and Hall resistivity measurements in magnetic fields up to μ0H = 40 T, the insulator–metal transition was found to occur when the magnetization reaches ∼2 μB/Eu for both (Hparallel [110]) and [001] at measurement temperatures above 50 K. Energy band calculations revealed that only the up-spin band, which is mainly composed of Te-5p electrons, crosses the Fermi level in the ferromagnetic state, although the energy band possesses a band gap in the paramagnetic and antiferromagnetic states.
我们利用 Te 自流式方法生长的单晶体，详细研究了具有四方晶体结构的 Eu 二价反铁磁体 EuTe2 的电学和磁学特性。在 TN = 11.1 K 以下的反铁磁态中观察到的各向异性磁化曲线可以从具有单轴磁性各向异性的反铁磁体的双子晶格模型的磁化过程来理解。这种化合物的一个特点是，在零磁场下，随着温度的降低，它变成了绝缘体，但在磁场中又变成了载流子数量相对较少的金属。从磁场高达 μ0H = 40 T 时的磁化、磁阻和霍尔电阻率测量结果来看，在测量温度高于 50 K 时，当 (Hparallel [110]) 和 [001] 的磁化率达到 ∼2 μB/Eu 时，绝缘体-金属转变就发生了。能带计算显示，尽管在顺磁态和反铁磁态中能带具有带隙，但在铁磁态中只有主要由 Te-5p 电子组成的上自旋带穿过费米级。
{"title":"Field-induced Insulator–Metal Transition in EuTe2","authors":"Tetsuya Takeuchi, Fuminori Honda, Dai Aoki, Yoshinori Haga, Takanori Kida, Yasuo Narumi, Masayuki Hagiwara, Koichi Kindo, Kosuke Karube, Hisatomo Harima, Yoshichika Ōnuki","doi":"10.7566/jpsj.93.044708","DOIUrl":"https://doi.org/10.7566/jpsj.93.044708","url":null,"abstract":"We studied in detail the electrical and magnetic properties of the Eu-divalent antiferromagnet EuTe<sub>2</sub> with a tetragonal crystal structure using single crystals grown by the Te self-flux method. The observed anisotropic magnetization curves in the antiferromagnetic state below <i>T</i><sub>N</sub> = 11.1 K can be understood in terms of the magnetization processes of the two-sublattice model of an antiferromagnet with uniaxial magnetic anisotropy. A characteristic feature of this compound is that it becomes an insulator with decreasing temperature at zero magnetic field, but changes to a metal with a relatively low number of carriers in magnetic fields. From the results of magnetization, magnetoresistance, and Hall resistivity measurements in magnetic fields up to <i>μ</i><sub>0</sub><i>H</i> = 40 T, the insulator–metal transition was found to occur when the magnetization reaches ∼2 <i>μ</i><sub>B</sub>/Eu for both <tex-math space=\"preserve\" version=\"MathJax\">(Hparallel [110])</tex-math> and [001] at measurement temperatures above 50 K. Energy band calculations revealed that only the up-spin band, which is mainly composed of Te-5<i>p</i> electrons, crosses the Fermi level in the ferromagnetic state, although the energy band possesses a band gap in the paramagnetic and antiferromagnetic states.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"39 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140312075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thermal conductivity κ of organic solutions containing m mole Fe(ClO4)26.0H2O and m mole Fe(ClO4)37.1H2O was investigated against m. The dimensionless figure of merit ZT is found to be larger in methanol (MeOH) and acetone solutions than that in aqueous solution. We further found that the corrected thermal conductivity (κcor) of organic solutions linearly decreases with increase in m and interpreted the reduction in terms of the suppression of intermolecular energy transfer.
我们研究了含有 m 摩尔 Fe(ClO4)26.0H2O 和 m 摩尔 Fe(ClO4)37.1H2O 的有机溶液的导热系数 κ 与 m 的关系。发现甲醇（MeOH）和丙酮溶液中的无量纲优度 ZT 比水溶液中的大。我们进一步发现，有机溶液的校正热导率 (κcor)随 m 的增大而线性减小，并从抑制分子间能量传递的角度解释了这种减小。
{"title":"Thermal Conductivity of Organic Solutions Against Solute Concentration","authors":"Kaisei Nishitani, Yutaka Moritomo","doi":"10.7566/jpsj.93.045002","DOIUrl":"https://doi.org/10.7566/jpsj.93.045002","url":null,"abstract":"Thermal conductivity <i>κ</i> of organic solutions containing <i>m</i> mole Fe(ClO<sub>4</sub>)<sub>2</sub>6.0H<sub>2</sub>O and <i>m</i> mole Fe(ClO<sub>4</sub>)<sub>3</sub>7.1H<sub>2</sub>O was investigated against <i>m</i>. The dimensionless figure of merit <i>ZT</i> is found to be larger in methanol (MeOH) and acetone solutions than that in aqueous solution. We further found that the corrected thermal conductivity (<i>κ</i><sub>cor</sub>) of organic solutions linearly decreases with increase in <i>m</i> and interpreted the reduction in terms of the suppression of intermolecular energy transfer.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"49 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140301538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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