The 0/1 matrix factorization defines matrix products using logical AND and OR as product-sum operators, revealing the factors influencing various decision processes. Instances and their characteristics are arranged in rows and columns. Formulating matrix factorization as an energy minimization problem and exploring it with Simulated Annealing (SA) theoretically enables finding a minimum solution in sufficient time. However, searching for the optimal solution in practical time becomes problematic when the energy landscape has many plateaus with flat slopes. In this work, we propose a method to facilitate the solution process by applying a gradient to the energy landscape, using a rectified linear type cost function readily available in modern annealing machines. We also propose a method to quickly obtain a solution by updating the cost function’s gradient during the search process. Numerical experiments were conducted, confirming the method’s effectiveness with both noise-free artificial and real data.
0/1 矩阵因式分解使用逻辑 AND 和 OR 作为乘积和运算符定义矩阵乘积，揭示影响各种决策过程的因素。实例及其特征按行和列排列。将矩阵因式分解表述为能量最小化问题，并用模拟退火（SA）进行探索，理论上可以在足够的时间内找到最小解。然而，当能量景观中存在许多具有平缓斜坡的高原时，在实际时间内寻找最优解就成了问题。在这项工作中，我们提出了一种方法，利用现代退火机器中易于获得的整顿线性成本函数，通过对能量景观应用梯度来促进求解过程。我们还提出了一种方法，通过在搜索过程中更新代价函数的梯度来快速获得解。我们进行了数值实验，通过无噪声人工数据和真实数据证实了该方法的有效性。
{"title":"Generating Gradients in the Energy Landscape Using Rectified Linear Type Cost Functions for Efficiently Solving 0/1 Matrix Factorization in Simulated Annealing","authors":"Makiko Konoshima, Hirotaka Tamura, Yoshiyuki Kabashima","doi":"10.7566/jpsj.93.044002","DOIUrl":"https://doi.org/10.7566/jpsj.93.044002","url":null,"abstract":"The 0/1 matrix factorization defines matrix products using logical AND and OR as product-sum operators, revealing the factors influencing various decision processes. Instances and their characteristics are arranged in rows and columns. Formulating matrix factorization as an energy minimization problem and exploring it with Simulated Annealing (SA) theoretically enables finding a minimum solution in sufficient time. However, searching for the optimal solution in practical time becomes problematic when the energy landscape has many plateaus with flat slopes. In this work, we propose a method to facilitate the solution process by applying a gradient to the energy landscape, using a rectified linear type cost function readily available in modern annealing machines. We also propose a method to quickly obtain a solution by updating the cost function’s gradient during the search process. Numerical experiments were conducted, confirming the method’s effectiveness with both noise-free artificial and real data.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"83 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140201166","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}
In this study, we first observed second-order primary rogue waves in solids by experiments using a modal based on primary waves. We found that the propagation of primary waves in solids can be described by the nonlinear Schrödinger equation. To enhance our understanding, we employed variational mode decomposition and identified the inherent frequency as the main factor. Therefore, we conducted spectral analysis to determine the frequency and discussed the results. The theoretical and experimental results are found to be in agreement, and our findings can be applied to the non destructive testing of large engineering structures.
{"title":"Observation of Primary Rogue Waves in Solids","authors":"Wei-Gang Zhao, Da-Wei Zuo, Xiu-Shu Tian, Xi-Yang Xie, Gao-Qing Meng","doi":"10.7566/jpsj.93.044001","DOIUrl":"https://doi.org/10.7566/jpsj.93.044001","url":null,"abstract":"In this study, we first observed second-order primary rogue waves in solids by experiments using a modal based on primary waves. We found that the propagation of primary waves in solids can be described by the nonlinear Schrödinger equation. To enhance our understanding, we employed variational mode decomposition and identified the inherent frequency as the main factor. Therefore, we conducted spectral analysis to determine the frequency and discussed the results. The theoretical and experimental results are found to be in agreement, and our findings can be applied to the non destructive testing of large engineering structures.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"153 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140169898","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}
Various single-crystal growth techniques have been presented for the unconventional superconductor UTe2. The molten salt flux liquid transport (MSFLT) method is employed to grow high-quality and large single crystals, exhibiting a high residual resistivity ratio (RRR ∼ 200–800). However, the Te self-flux and chemical vapor transport (CVT) methods produce samples of lower quality. The MSFLT method is a hybrid approach combining the molten salt flux (MSF) and CVT methods. One significant advantage is that the materials gradually crystallize at a relatively low temperature, which is maintained throughout the main process. This may be crucial for preventing U deficiency and obtaining high-quality large single crystals of UTe2. Many different single crystals obtained using different techniques have been characterized by resistivity and specific heat measurements. The superconducting transition temperature Tc decreases with residual resistivity ρ0, followed by the Abrikosov–Gor’kov pair-breaking theory, and reaches 2.1 K for ρ0 → 0. The residual γ-value of the specific heat for the highest quality sample was only 3% of the normal-state γ-value. The specific heat jump, ΔCe/(γTc) reached approximately 2.7 for high-quality samples, indicating a strong-coupling superconductor. Furthermore, the magnetic susceptibility for H || a-axis in a high-quality single crystal does not show an up-turn behavior on cooling, which is consistent with the results of NMR Knight shift and μSR experiments.
{"title":"Molten Salt Flux Liquid Transport Method for Ultra Clean Single Crystals UTe2","authors":"Dai Aoki","doi":"10.7566/jpsj.93.043703","DOIUrl":"https://doi.org/10.7566/jpsj.93.043703","url":null,"abstract":"Various single-crystal growth techniques have been presented for the unconventional superconductor UTe<sub>2</sub>. The molten salt flux liquid transport (MSFLT) method is employed to grow high-quality and large single crystals, exhibiting a high residual resistivity ratio (RRR ∼ 200–800). However, the Te self-flux and chemical vapor transport (CVT) methods produce samples of lower quality. The MSFLT method is a hybrid approach combining the molten salt flux (MSF) and CVT methods. One significant advantage is that the materials gradually crystallize at a relatively low temperature, which is maintained throughout the main process. This may be crucial for preventing U deficiency and obtaining high-quality large single crystals of UTe<sub>2</sub>. Many different single crystals obtained using different techniques have been characterized by resistivity and specific heat measurements. The superconducting transition temperature <i>T</i><sub>c</sub> decreases with residual resistivity <i>ρ</i><sub>0</sub>, followed by the Abrikosov–Gor’kov pair-breaking theory, and reaches 2.1 K for <i>ρ</i><sub>0</sub> → 0. The residual <i>γ</i>-value of the specific heat for the highest quality sample was only 3% of the normal-state <i>γ</i>-value. The specific heat jump, Δ<i>C</i><sub>e</sub>/(<i>γT</i><sub>c</sub>) reached approximately 2.7 for high-quality samples, indicating a strong-coupling superconductor. Furthermore, the magnetic susceptibility for <i>H</i> || <i>a</i>-axis in a high-quality single crystal does not show an up-turn behavior on cooling, which is consistent with the results of NMR Knight shift and <i>μ</i>SR experiments.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"8 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140124270","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 various magnetic orders observed in approximant crystals of a Tsai-type quasicrystal are important for deepening our understanding of magnetism in quasicrystals. Using an icosahedral cluster model with intercluster interactions, we provide an intuitive explanation of the mechanism of magnetic orders previously reported by classical Monte Carlo simulations of an effective Heisenberg model for Gd-based Tsai-type 1/1 approximant crystals.
{"title":"Revisiting the Magnetic Orders in Heisenberg Model for Tsai-Type Quasicrystal Approximant","authors":"Takanori Sugimoto, Shintaro Suzuki, Ryuji Tamura, Takami Tohyama","doi":"10.7566/jpsj.93.045001","DOIUrl":"https://doi.org/10.7566/jpsj.93.045001","url":null,"abstract":"The various magnetic orders observed in approximant crystals of a Tsai-type quasicrystal are important for deepening our understanding of magnetism in quasicrystals. Using an icosahedral cluster model with intercluster interactions, we provide an intuitive explanation of the mechanism of magnetic orders previously reported by classical Monte Carlo simulations of an effective Heisenberg model for Gd-based Tsai-type 1/1 approximant crystals.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"30 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140075429","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}
In this paper, we derive a real-space topological invariant that involves all energy states in the system. This global invariant, denoted by Q, is always quantized to be 0 or 1, independent of symmetries. In terms of Q, we numerically investigate topological properties of the nonchiral Rice–Mele model including random onsite potentials to show that nontrivial bulk topology is sustained for weak enough disorder. In this regime, a finite spectral gap persists, and then Q is definitely identified. We also consider sublattice polarization of disorder potentials. In this case, the energy spectrum retains a gap regardless of disorder strength so that Q is unaffected by disorder. This implies that bulk topology remains intact as long as the spectral gap opens.
{"title":"Real-Space Formulation of Topology for Disordered Rice–Mele Chains without Chiral Symmetry","authors":"Kiminori Hattori, Ata Yamaguchi","doi":"10.7566/jpsj.93.044702","DOIUrl":"https://doi.org/10.7566/jpsj.93.044702","url":null,"abstract":"In this paper, we derive a real-space topological invariant that involves all energy states in the system. This global invariant, denoted by <i>Q</i>, is always quantized to be 0 or 1, independent of symmetries. In terms of <i>Q</i>, we numerically investigate topological properties of the nonchiral Rice–Mele model including random onsite potentials to show that nontrivial bulk topology is sustained for weak enough disorder. In this regime, a finite spectral gap persists, and then <i>Q</i> is definitely identified. We also consider sublattice polarization of disorder potentials. In this case, the energy spectrum retains a gap regardless of disorder strength so that <i>Q</i> is unaffected by disorder. This implies that bulk topology remains intact as long as the spectral gap opens.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"45 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140025066","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 phase transitions from a nematic liquid-crystal phase to an isotropic phase are reported in this study. The phase transition temperature Tc under noise and DC fields was examined during continuous heating processes with different heating rates R (1–10 °C/min). Tc was determined as functions of the noise intensity VN and the DC intensity V. Evidently, Tc shows different behavior with respect to the fields at fixed values of R. Tc decreased monotonously with VN, whereas it exhibited nonmonotonic behavior in Tc(V). These shifts in Tc are quite different from that previously observed in the AC field. It was found that DC field-induced electroconvection is responsible for the unexpected nonmonotonic behavior. In particular, the transition between the dynamic scattering modes (i.e., DSM1 and DSM2) may be related to this behavior. The different behavior for the noise and DC fields was confirmed using various values of R. Furthermore, the present results in comparison with the previous results for the AC field were discussed.
本研究报告了从向列液晶相到各向同性相的热相变。在不同加热速率 R（1-10 °C/分钟）的连续加热过程中，考察了噪声和直流电场下的相变温度 Tc。Tc 随噪声强度 VN 和直流强度 V 的变化而单调下降，而 Tc(V) 则表现出非单调性。Tc 的这些变化与之前在交流场中观察到的变化截然不同。研究发现，直流电场诱导的电对流是造成这种意想不到的非单调行为的原因。特别是动态散射模式（即 DSM1 和 DSM2）之间的转换可能与这种行为有关。使用不同的 R 值证实了噪声场和直流场的不同行为。
{"title":"Phase Transition Temperatures of a Nematic Liquid Crystal in the Presence of Noise and DC Fields","authors":"Jong-Hoon Huh, Takumu Higashi, Tatsuya Yamasaki, Tomoyuki Nagaya","doi":"10.7566/jpsj.93.044601","DOIUrl":"https://doi.org/10.7566/jpsj.93.044601","url":null,"abstract":"Thermal phase transitions from a nematic liquid-crystal phase to an isotropic phase are reported in this study. The phase transition temperature <i>T</i><sub>c</sub> under noise and DC fields was examined during continuous heating processes with different heating rates <i>R</i> (1–10 °C/min). <i>T</i><sub>c</sub> was determined as functions of the noise intensity <i>V</i><sub>N</sub> and the DC intensity <i>V</i>. Evidently, <i>T</i><sub>c</sub> shows different behavior with respect to the fields at fixed values of <i>R</i>. <i>T</i><sub>c</sub> decreased monotonously with <i>V</i><sub>N</sub>, whereas it exhibited nonmonotonic behavior in <i>T</i><sub>c</sub>(<i>V</i>). These shifts in <i>T</i><sub>c</sub> are quite different from that previously observed in the AC field. It was found that DC field-induced electroconvection is responsible for the unexpected nonmonotonic behavior. In particular, the transition between the dynamic scattering modes (i.e., DSM1 and DSM2) may be related to this behavior. The different behavior for the noise and DC fields was confirmed using various values of <i>R</i>. Furthermore, the present results in comparison with the previous results for the AC field were discussed.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"47 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140025093","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}
Superconductivity in the two-band Hubbard model characterized by the on-site Coulomb repulsion Ud at d-site and the charge-transfer energy Δ between d- and p-sites is investigated on the basis of the dynamical mean-field theory. We calculate the pair susceptibilities for the s-wave symmetries with spin-singlet even-frequency and spin-triplet odd-frequency pairings and determine the superconducting transition temperature Tc at which the pair susceptibilities diverge. In the strong correlation regime where the system becomes Mott insulator at half-filling, the triplet superconductivity takes place in underdoped region while the singlet one takes place in overdoped region. In the both cases, Tc shows a maximum in the crossover region between Mott–Hubbard type (Ud < Δ) and charge-transfer type (Ud > Δ). We also observe a remarkable BEC-BCS crossover at a slightly doped region in the triplet superconductivity.
我们以动态均场理论为基础，研究了双带哈伯德模型中的超导性，其特征是 d 位的现场库仑斥力 Ud 以及 d 位和 p 位之间的电荷转移能 Δ。我们计算了具有自旋-小偶频和自旋-三偶频配对的 s 波对称性的配对感生，并确定了配对感生发散时的超导转变温度 Tc。在半填充时系统成为莫特绝缘体的强相关体系中，三重超导发生在掺杂不足区域，而单重超导发生在掺杂过度区域。在这两种情况下，Tc 在莫特哈伯德型（Ud < Δ）和电荷转移型（Ud > Δ）之间的交叉区域都显示出最大值。我们还在三重超导的轻微掺杂区域观察到了显著的 BEC-BCS 交叉。
{"title":"Singlet Even-Frequency and Triplet Odd-Frequency Superconductivity in the Two-Band Hubbard Model Based on the Dynamical Mean-Field Theory","authors":"Yusuke Inokuma, Yoshiaki Ōno","doi":"10.7566/jpsj.93.043701","DOIUrl":"https://doi.org/10.7566/jpsj.93.043701","url":null,"abstract":"Superconductivity in the two-band Hubbard model characterized by the on-site Coulomb repulsion <i>U<sub>d</sub></i> at <i>d</i>-site and the charge-transfer energy Δ between <i>d</i>- and <i>p</i>-sites is investigated on the basis of the dynamical mean-field theory. We calculate the pair susceptibilities for the <i>s</i>-wave symmetries with spin-singlet even-frequency and spin-triplet odd-frequency pairings and determine the superconducting transition temperature <i>T</i><sub>c</sub> at which the pair susceptibilities diverge. In the strong correlation regime where the system becomes Mott insulator at half-filling, the triplet superconductivity takes place in underdoped region while the singlet one takes place in overdoped region. In the both cases, <i>T</i><sub>c</sub> shows a maximum in the crossover region between Mott–Hubbard type (<i>U<sub>d</sub></i> < Δ) and charge-transfer type (<i>U<sub>d</sub></i> > Δ). We also observe a remarkable BEC-BCS crossover at a slightly doped region in the triplet superconductivity.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"263 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140025060","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}
Untethered microswimmers are essential for various applications. Here, we propose a thermally driven untethered swimmer using a convection flow with the eddy current loss due to AC magnetic fields and examine the performance of the swimmer. Specifically, we demonstrate that a floating object with a Cu oblique beam can be moved at a velocity of up to 1.8 mm/s by applying an AC magnetic field of 10.2 mT with a frequency of 11.7 kHz. Furthermore, by measuring the temperature of the Cu plate under the magnetic field, we clarify the role of the eddy current. In addition, we clarify the design concept of the convective swimmer from measurements at various angles of the oblique beam and applied magnetic fields. Our findings should contribute to the development of innovative untethered thermally driven microrobots and microswimmers.
{"title":"Thermally Driven Untethered Swimmer Using a Convection Flow with the Eddy Current Loss Due to AC Magnetic Fields","authors":"Hideyuki Sugioka, Ryo Takeda","doi":"10.7566/jpsj.93.034802","DOIUrl":"https://doi.org/10.7566/jpsj.93.034802","url":null,"abstract":"Untethered microswimmers are essential for various applications. Here, we propose a thermally driven untethered swimmer using a convection flow with the eddy current loss due to AC magnetic fields and examine the performance of the swimmer. Specifically, we demonstrate that a floating object with a Cu oblique beam can be moved at a velocity of up to 1.8 mm/s by applying an AC magnetic field of 10.2 mT with a frequency of 11.7 kHz. Furthermore, by measuring the temperature of the Cu plate under the magnetic field, we clarify the role of the eddy current. In addition, we clarify the design concept of the convective swimmer from measurements at various angles of the oblique beam and applied magnetic fields. Our findings should contribute to the development of innovative untethered thermally driven microrobots and microswimmers.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"50 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140003106","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 studied the quadrupolar Kondo effect for an impurity in cubic environment with taking account of a singlet excited state Γ1, which models a Pr3+ ion with a non-Kramers double ground state Γ3. We have used the numerical renormalization group approach and determined the phase diagram with varying quadrupole Kondo coupling J and Γ1 excitation energy Δ. Two phases are found and identified as local Fermi liquid and non-Fermi liquid. This non-Fermi liquid phase is characteristic to the two-channel Kondo impurity, and a similar phase diagram has been also found in other extended quadrupole models. We have analyzed in detail the J-dependence of the Kondo temperature TK near the phase boundary Jc(Δ) and found a nice scaling behavior with an stretched exponential form TK ∼ δJα exp(−const./(sqrt{delta J} )) where δJ ≡ J − Jc(Δ). This differs from the standard scaling form and indicates that one needs to consider renormalization of multiple coupling constants.
{"title":"Numerical Renormalization Group Study of Quadrupole Kondo Effect with the Crystal-Field Excited State","authors":"Yuki Kaneko, Hirokazu Tsunetsugu","doi":"10.7566/jpsj.93.033705","DOIUrl":"https://doi.org/10.7566/jpsj.93.033705","url":null,"abstract":"We have studied the quadrupolar Kondo effect for an impurity in cubic environment with taking account of a singlet excited state Γ<sub>1</sub>, which models a Pr<sup>3+</sup> ion with a non-Kramers double ground state Γ<sub>3</sub>. We have used the numerical renormalization group approach and determined the phase diagram with varying quadrupole Kondo coupling <i>J</i> and Γ<sub>1</sub> excitation energy Δ. Two phases are found and identified as local Fermi liquid and non-Fermi liquid. This non-Fermi liquid phase is characteristic to the two-channel Kondo impurity, and a similar phase diagram has been also found in other extended quadrupole models. We have analyzed in detail the <i>J</i>-dependence of the Kondo temperature <i>T<sub>K</sub></i> near the phase boundary <i>J<sub>c</sub></i>(Δ) and found a nice scaling behavior with an stretched exponential form <i>T<sub>K</sub></i> ∼ <i>δJ<sup>α</sup></i> exp(−const./<tex-math space=\"preserve\" version=\"MathJax\">(sqrt{delta J} )</tex-math>) where <i>δJ</i> ≡ <i>J</i> − <i>J<sub>c</sub></i>(Δ). This differs from the standard scaling form and indicates that one needs to consider renormalization of multiple coupling constants.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"28 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140003343","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}
Chiral phonons with atomic rotations converted into electron spins result in a change of spin magnetizations in crystals. In this paper, we investigate a new conversion of chiral phonons into magnons both in ferromagnets and antiferromagnets by spin models with exchange and Dzyaloshinskii–Moriya interactions. The atomic rotations in chiral phonons are treated as slow phonons, which modulate spin–spin interaction and induce time-dependent magnon excitations due to geometric effect within adiabatic approximation. We demonstrate that a non-trivial change of the number of magnons requires breaking of the spin-rotation symmetry around the spin quantization axis. As a result, the clockwise and counterclockwise chiral phonons induce a change of the magnon number with opposite signs, which corresponds to an increasing or decreasing spin magnetization due to the chiral nature of the atomic rotations. In particular, in antiferromagnets, the modulation of magnons due to chiral phonons generates a non-zero net magnetization by the proposed effect, which is expect to be observed in experiments.
{"title":"Conversion of Chiral Phonons into Magnons in Ferromagnets and Antiferromagnets","authors":"Dapeng Yao, Shuichi Murakami","doi":"10.7566/jpsj.93.034708","DOIUrl":"https://doi.org/10.7566/jpsj.93.034708","url":null,"abstract":"Chiral phonons with atomic rotations converted into electron spins result in a change of spin magnetizations in crystals. In this paper, we investigate a new conversion of chiral phonons into magnons both in ferromagnets and antiferromagnets by spin models with exchange and Dzyaloshinskii–Moriya interactions. The atomic rotations in chiral phonons are treated as slow phonons, which modulate spin–spin interaction and induce time-dependent magnon excitations due to geometric effect within adiabatic approximation. We demonstrate that a non-trivial change of the number of magnons requires breaking of the spin-rotation symmetry around the spin quantization axis. As a result, the clockwise and counterclockwise chiral phonons induce a change of the magnon number with opposite signs, which corresponds to an increasing or decreasing spin magnetization due to the chiral nature of the atomic rotations. In particular, in antiferromagnets, the modulation of magnons due to chiral phonons generates a non-zero net magnetization by the proposed effect, which is expect to be observed in experiments.","PeriodicalId":17304,"journal":{"name":"Journal of the Physical Society of Japan","volume":"2017 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140003606","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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