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Thermodynamics of the anisotropic Heisenberg ferromagnet at low temperature 各向异性海森堡铁磁体的低温热力学
Physica Pub Date : 1974-10-15 DOI: 10.1016/0031-8914(74)90270-5
M. Brunné, M. Drzazga
{"title":"Thermodynamics of the anisotropic Heisenberg ferromagnet at low temperature","authors":"M. Brunné,&nbsp;M. Drzazga","doi":"10.1016/0031-8914(74)90270-5","DOIUrl":"10.1016/0031-8914(74)90270-5","url":null,"abstract":"<div><p>The Heisenberg ferromagnet with exchange and crystal-field anisotropies is studied. The free energy and magnetization are calculated by means of a method developed by Wortis.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"77 2","pages":"Pages 403-417"},"PeriodicalIF":0.0,"publicationDate":"1974-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90270-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85817461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Some exact results in the boson formulation of superconductivity 超导玻色子公式中的一些精确结果
Physica Pub Date : 1974-10-15 DOI: 10.1016/0031-8914(74)90263-8
F. Mancini
{"title":"Some exact results in the boson formulation of superconductivity","authors":"F. Mancini","doi":"10.1016/0031-8914(74)90263-8","DOIUrl":"10.1016/0031-8914(74)90263-8","url":null,"abstract":"<div><p>The boson formulation of superconductivity is derived quite generally without resorting to power-series expansions in the momentum. An exact form for the boson characteristic function is given in terms of the boson energy. An exact equation for the boson energy is also derived. By solving this equation one can compute the boson characteristic function in the entire domain of momentum. This result implies that one can describe spatial variations of the order parameter and of the magnetic field without any practical restriction.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"77 2","pages":"Pages 311-331"},"PeriodicalIF":0.0,"publicationDate":"1974-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90263-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88224994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 8
A charged particle in a uniform electromagnetic field a group-theoretical analysis 均匀电磁场中的带电粒子。群论分析
Physica Pub Date : 1974-10-15 DOI: 10.1016/0031-8914(74)90262-6
L.C. Chen , T. Janssen
{"title":"A charged particle in a uniform electromagnetic field a group-theoretical analysis","authors":"L.C. Chen ,&nbsp;T. Janssen","doi":"10.1016/0031-8914(74)90262-6","DOIUrl":"10.1016/0031-8914(74)90262-6","url":null,"abstract":"<div><p>A new covariant derivation is given for the relativistic symmetry group of a uniform electromagnetic field. The symmetry group of the equations of motion of a charged (classical, Klein-Gordon or Dirac) particle in such a field and its irreducible representations are determined. Using the representations the solutions of the equations of motion are discussed. Exact solutions can be given for the motion of a charged particle in an arbitrary uniform field.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"77 2","pages":"Pages 290-310"},"PeriodicalIF":0.0,"publicationDate":"1974-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90262-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72844014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
Dirac's hamiltonian formalism and gauge-invariant classical electrodynamics 狄拉克的哈密顿形式论与标准不变经典电动力学
Physica Pub Date : 1974-10-15 DOI: 10.1016/0031-8914(74)90272-9
J. Vardalas
{"title":"Dirac's hamiltonian formalism and gauge-invariant classical electrodynamics","authors":"J. Vardalas","doi":"10.1016/0031-8914(74)90272-9","DOIUrl":"10.1016/0031-8914(74)90272-9","url":null,"abstract":"<div><p>Using Dirac's method of constraints we study the problem of a gauge-invariant hamiltonian formulation of a relativistic plasma. In particular we get a hamiltonian formulation strictly in terms of the electric and magnetic fields, and the mechanical momenta of the particles. The explicit Lie-bracket relations between the fundamental microscopic variables is no longer canonical. These Lie-bracket relations and the equations of motion are given by Dirac's modified Poisson bracket.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"77 2","pages":"Pages 431-439"},"PeriodicalIF":0.0,"publicationDate":"1974-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90272-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87387070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Stochastic nonlinear differential equations. I 随机非线性微分方程。我
Physica Pub Date : 1974-10-15 DOI: 10.1016/0031-8914(74)90261-4
O.J. Heilmann, N.G. Van Kampen
{"title":"Stochastic nonlinear differential equations. I","authors":"O.J. Heilmann,&nbsp;N.G. Van Kampen","doi":"10.1016/0031-8914(74)90261-4","DOIUrl":"10.1016/0031-8914(74)90261-4","url":null,"abstract":"<div><p>A solution method is developed for nonlinear differential equations having the following two properties. Their coefficients are stochastic through their dependence on a Markov process. The magnitude of the fluctuations, multiplied with their auto-correlation time, is a small quantity. Under these conditions, the solution is also approximately a Markov process. Its probability distribution obeys a master equation, whose kernel is found as an expansion in that small quantity. The general formula is derived. Applications will be given in the second part of this work.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"77 2","pages":"Pages 279-289"},"PeriodicalIF":0.0,"publicationDate":"1974-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90261-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73282900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
A new method for evaluating Gaussian path integrals 求高斯路径积分的一种新方法
Physica Pub Date : 1974-10-15 DOI: 10.1016/0031-8914(74)90268-7
M.J. Goovaerts
{"title":"A new method for evaluating Gaussian path integrals","authors":"M.J. Goovaerts","doi":"10.1016/0031-8914(74)90268-7","DOIUrl":"10.1016/0031-8914(74)90268-7","url":null,"abstract":"<div><p>A new method for evaluating the path integral corresponding to the harmonic oscillator with time-dependent frequency Ω(<em>t</em>) and acted on by a time-dependent perturbative force is given. The advantage of the present method consists in the fact that our analytical expression for this path integral can immediately be expanded as a series in the eigenfunctions of the corresponding Schrödinger equation.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"77 2","pages":"Pages 379-389"},"PeriodicalIF":0.0,"publicationDate":"1974-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90268-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77738311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 6
A complete computation of the boson characteristic function at T = 0 K T = 0 K时玻色子特征函数的完整计算
Physica Pub Date : 1974-10-15 DOI: 10.1016/0031-8914(74)90264-X
G.F. De Angelis, F. Mancini
{"title":"A complete computation of the boson characteristic function at T = 0 K","authors":"G.F. De Angelis,&nbsp;F. Mancini","doi":"10.1016/0031-8914(74)90264-X","DOIUrl":"10.1016/0031-8914(74)90264-X","url":null,"abstract":"<div><p>The boson characteristic function is computed in the entire region of momenta. A comparison with the BCS kernel is discussed.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"77 2","pages":"Pages 332-342"},"PeriodicalIF":0.0,"publicationDate":"1974-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90264-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90239589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 8
Low-temperature isotopic thermal diffusion of neon 氖的低温同位素热扩散
Physica Pub Date : 1974-10-15 DOI: 10.1016/0031-8914(74)90271-7
M.Áurea Cunha, M.F. Laranjeira
{"title":"Low-temperature isotopic thermal diffusion of neon","authors":"M.Áurea Cunha,&nbsp;M.F. Laranjeira","doi":"10.1016/0031-8914(74)90271-7","DOIUrl":"https://doi.org/10.1016/0031-8914(74)90271-7","url":null,"abstract":"<div><p>Isotopic thermal-diffusion factors have been determined for neon, in the temperature range from 139.6 up to 302.3 K.</p><p>In our previous observations, a wide temperature range from about 140 to 803 K has been experimentally covered and used to test the exponential-six model. Theoretical calculations with other properties (viscosity, thermal conductivity, self-diffusion and second virial coefficient) have been also considered within the frame-work of the model.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"77 2","pages":"Pages 418-430"},"PeriodicalIF":0.0,"publicationDate":"1974-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90271-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136424394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Entropy, dynamics and molecular chaos, Kac's model 熵，动力学和分子混沌，Kac的模型
Physica Pub Date : 1974-10-15 DOI: 10.1016/0031-8914(74)90258-4
F. Henin
{"title":"Entropy, dynamics and molecular chaos, Kac's model","authors":"F. Henin","doi":"10.1016/0031-8914(74)90258-4","DOIUrl":"10.1016/0031-8914(74)90258-4","url":null,"abstract":"<div><p>We use a model due to Kac to investigate some properties of the generalized entropy proposed by the Brussels group. We show that the entropy production is positive-definite and that the entropy and entropy production per particle are finite in the limit of an infinite system.</p><p>The generalized <span><math><mtext>H</mtext></math></span> theorem is a dynamical theorem and describes the approach to equilibrium of the whole system: generally, correlations play a role in its formulation and cannot be forgotten even if macroscopic variables satisfy the chaos condition. However, a detailed investigation of the evolution equations for the moments shows that correlations reach their equilibrium value faster than the one-particle reduced distribution function and that, asymptotically, there is a regime where one recovers Boltzmann's results.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"77 2","pages":"Pages 220-246"},"PeriodicalIF":0.0,"publicationDate":"1974-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90258-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90076135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
The Luttinger-Tisza method Luttinger-Tisza方法
Physica Pub Date : 1974-10-15 DOI: 10.1016/0031-8914(74)90257-2
D.B. Litvin
{"title":"The Luttinger-Tisza method","authors":"D.B. Litvin","doi":"10.1016/0031-8914(74)90257-2","DOIUrl":"10.1016/0031-8914(74)90257-2","url":null,"abstract":"<div><p>The Luttinger-Tisza method and generalizations of this method for determining the minimum energy spin arrangement in a crystal subject to certain strong conditions are reviewed. It is shown that one can always replace the strong conditions by a set of additional conditions which in the simplest cases is identical with the single weak condition introduced in the Luttinger-Tisza method. A general method of calculating the minimum energy spin arrangement, based on the space group symmetry of the magnetic atom arrangements, is given, and the method of Niemeyer, based on permutation groups, is shown to be equivalent to this method. It is also known that the Luttinger-Tisza conjecture concerning the periodicity of the minimum energy spin arrangement is equivalent to a sufficient, but not necessary, condition for a minimum of the energy.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"77 2","pages":"Pages 205-219"},"PeriodicalIF":0.0,"publicationDate":"1974-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90257-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79819099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 30
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