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A generalized Landau theory for the two-dimensional Ising model 二维Ising模型的广义朗道理论
Physica Pub Date : 1974-11-15 DOI: 10.1016/0031-8914(74)90313-9
M. Luban, E. Asscher
{"title":"A generalized Landau theory for the two-dimensional Ising model","authors":"M. Luban,&nbsp;E. Asscher","doi":"10.1016/0031-8914(74)90313-9","DOIUrl":"https://doi.org/10.1016/0031-8914(74)90313-9","url":null,"abstract":"<div><p>A free-energy functional is proposed for the two-dimensional Ising model below <em>T</em><sub>c</sub> which incorporates the correct critical exponents and the anomalous behaviour of the order-parameter correlation function.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"78 1","pages":"Pages 113-130"},"PeriodicalIF":0.0,"publicationDate":"1974-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90313-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91759687","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
Master equation for nonstationary states of an electron interacting with phonons 电子与声子相互作用的非定常状态的主方程
Physica Pub Date : 1974-11-15 DOI: 10.1016/0031-8914(74)90307-3
D.J. Bergman, O. Entin-Wohlman
{"title":"Master equation for nonstationary states of an electron interacting with phonons","authors":"D.J. Bergman,&nbsp;O. Entin-Wohlman","doi":"10.1016/0031-8914(74)90307-3","DOIUrl":"10.1016/0031-8914(74)90307-3","url":null,"abstract":"<div><p>We consider the dissipative effects of electron-phonon interactions on electron states which are not eigenstates of the pure electron hamiltonian. A master-equation formalism is developed to calculate the time evolution of the occupation probabilities of these states as well as other elements of the reduced single-electron density matrix. Conditions are found which ensure that the master equations are markoffian. It is suggested that markofficity rather than approximate stationarity is the important criterion for the usefulness of a basis of states for the description of the evolution of a physical system.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"78 1","pages":"Pages 31-44"},"PeriodicalIF":0.0,"publicationDate":"1974-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90307-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80530543","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: 1
Composition dependence of the thermal-diffusion factor of Ne-Kr mixtures Ne-Kr混合物热扩散系数的组分依赖性
Physica Pub Date : 1974-11-15 DOI: 10.1016/0031-8914(74)90317-6
C.M. Santamaría, J.M. Savirón, J.C. Yarza
{"title":"Composition dependence of the thermal-diffusion factor of Ne-Kr mixtures","authors":"C.M. Santamaría,&nbsp;J.M. Savirón,&nbsp;J.C. Yarza","doi":"10.1016/0031-8914(74)90317-6","DOIUrl":"10.1016/0031-8914(74)90317-6","url":null,"abstract":"<div><p>Experimental results for six binary mixtures of Ne and Kr obtained in a two-bulb apparatus operated at 77.6 K and 308 K are presented. The composition dependence of α<sub><em>T</em></sub> is compared with the results of the Chapman-Enskog theory. The empirical potential of Kestin, Ro and Wakeham is able to explain the experimental dependence of α<sub><em>T</em></sub> on the composition at our working temperature. The same comparison with the results of other authors, at around room temperature, indicates an equally good agreement.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"78 1","pages":"Pages 165-172"},"PeriodicalIF":0.0,"publicationDate":"1974-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90317-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72488326","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
Chain approximations in the perturbation theory of liquids 液体微扰理论中的链式近似
Physica Pub Date : 1974-11-15 DOI: 10.1016/0031-8914(74)90318-8
A. Fuliński, C. Jȩdrzejek
{"title":"Chain approximations in the perturbation theory of liquids","authors":"A. Fuliński,&nbsp;C. Jȩdrzejek","doi":"10.1016/0031-8914(74)90318-8","DOIUrl":"https://doi.org/10.1016/0031-8914(74)90318-8","url":null,"abstract":"<div><p>Two recent versions of the perturbation theory of liquids, the optimized chain approximation of Andersen, Chandler and Weeks (ACW) and the renormalized one-chain approximation (ROC) by one of us (AF), are discussed. The ACW optimized version leads to better results than the ROC one. The main difference between these versions lies in the definition of the renormalized perturbation bond. The ACW form enables the optimization of the chain sum by the adjustment of the perturbation potential inside the hard core. This is impossible in the ROC approximation, which, however, may be ‘optimized’ by the replacement of the complete hard-sphere radial distribution function by its zeroth-order approximation. Both of these optimalization procedures are equivalent to the effective weakening of the repulsive interactions of the reference system. We infer that the hard-sphere fluid is too strongly repulsive to be the best reference system for perturbation theories of liquids.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"78 1","pages":"Pages 173-182"},"PeriodicalIF":0.0,"publicationDate":"1974-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90318-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91725730","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: 1
Viscosity and polar-nonpolar interactions in mixtures of inert gases with ammonia 惰性气体与氨混合物中的粘度和极性-非极性相互作用
Physica Pub Date : 1974-11-15 DOI: 10.1016/0031-8914(74)90316-4
A.B. Rakshit, C.S. Roy
{"title":"Viscosity and polar-nonpolar interactions in mixtures of inert gases with ammonia","authors":"A.B. Rakshit,&nbsp;C.S. Roy","doi":"10.1016/0031-8914(74)90316-4","DOIUrl":"10.1016/0031-8914(74)90316-4","url":null,"abstract":"<div><p>The viscosities of the binary gas mixtures He-NH<sub>3</sub>, Ne-NH<sub>3</sub>, Kr-NH<sub>3</sub> and Xe-NH<sub>3</sub> have been measured by the oscillating-disc method in the temperature range from -35°C to 35°C. The experimental data are systematically higher than the calculated values obtained by using the conventional combination rules for the parameters of the interaction potential for the polar-nonpolar interaction which includes the dipole-induced dipole term only. The discrepancy increases from He to Xe. These results are consistent with those obtained previously for mixtures of CH<sub>3</sub>Cl gas with the inert gases. It has been suggested that the major cause of the discrepancy is the neglect of the <em>r</em><sup>−7</sup> term in the interaction between a polar and a nonpolar molecule.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"78 1","pages":"Pages 153-164"},"PeriodicalIF":0.0,"publicationDate":"1974-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90316-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87503182","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
Deterioration of the molecular field 分子场的退化
Physica Pub Date : 1974-11-15 DOI: 10.1016/0031-8914(74)90310-3
H. Falk , Th.W. Ruijgrok
{"title":"Deterioration of the molecular field","authors":"H. Falk ,&nbsp;Th.W. Ruijgrok","doi":"10.1016/0031-8914(74)90310-3","DOIUrl":"https://doi.org/10.1016/0031-8914(74)90310-3","url":null,"abstract":"<div><p>The molecular-field model of an Ising ferromagnet is modified by cutting interaction bonds so as to leave a system of <em>M</em> chains with long-range interactions between nearest-neighbor chains only. Equilibrium properties of the model, such as the critical temperature.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"78 1","pages":"Pages 73-90"},"PeriodicalIF":0.0,"publicationDate":"1974-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90310-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91725728","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
Exact photocount statistics of linearly unstable gaussian light 线性不稳定高斯光的精确光计数统计
Physica Pub Date : 1974-11-15 DOI: 10.1016/0031-8914(74)90306-1
W. Wonneberger
{"title":"Exact photocount statistics of linearly unstable gaussian light","authors":"W. Wonneberger","doi":"10.1016/0031-8914(74)90306-1","DOIUrl":"https://doi.org/10.1016/0031-8914(74)90306-1","url":null,"abstract":"<div><p>The theory of the long-time photocount statistics of a linear gaussian light wave is extended into the unstable region characterized by a gain constant Λ. Exact recurrence relations for the photocount distribution and the normalized factorial moments are given and the distribution function <em>P</em>(<em>E</em>) of the integrated light intensity <em>E</em> is discussed. Due to the exponential increase of mean intensity during the counting interval <em>T</em> only a limited amount of amplitude stabilization can occur in <em>E</em> provided Λ<em>T</em> ≲1. For Λ<em>T</em> ⪡1 and Λ<em>T</em> ⪢1 the distribution <em>P</em>(<em>E</em>) is thermal. A new parameter <em>r</em> appears in the theory measuring the initial wave intensity in relation to the quantum fluctuations. For <em>r</em> ⪢ 1, <em>P</em>(<em>E</em>) is practically thermal for all values of Λ<em>T</em>. For <em>r</em>≲1 characteristic deviations from a thermal distribution appear which provide a means to measure the linear gain Λ of the light wave by photon counting.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"78 1","pages":"Pages 22-30"},"PeriodicalIF":0.0,"publicationDate":"1974-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90306-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91725726","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: 1
The Ehrenfest theorem and gas transport properties 埃伦费斯特定理和气体输运性质
Physica Pub Date : 1974-11-15 DOI: 10.1016/0031-8914(74)90309-7
L. Monchick
{"title":"The Ehrenfest theorem and gas transport properties","authors":"L. Monchick","doi":"10.1016/0031-8914(74)90309-7","DOIUrl":"https://doi.org/10.1016/0031-8914(74)90309-7","url":null,"abstract":"<div><p>It is shown that the momentum transfer theorem implies a rough correlation of the diffusion cross section with the slope of the intermolecular potential energy. This is a particular case of the collision Ehrenfest theorem which can be applied in like manner to all of the collision cross sections arising in kinetic theory, thus allowing a qualitative discussion of their dependence on the potential. As an example, relative to the diffusion cross section the viscosity has an increased sensitivity to the curvature of the potential.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"78 1","pages":"Pages 64-72"},"PeriodicalIF":0.0,"publicationDate":"1974-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90309-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91725727","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
The influence of surface irregularities upon the Van der Waals forces between macroscopic bodies 表面不规则性对宏观体间范德华力的影响
Physica Pub Date : 1974-11-15 DOI: 10.1016/0031-8914(74)90320-6
J.L.M.J. Van Bree, J.A. Poulis, B.J. Verhaar, K. Schram
{"title":"The influence of surface irregularities upon the Van der Waals forces between macroscopic bodies","authors":"J.L.M.J. Van Bree,&nbsp;J.A. Poulis,&nbsp;B.J. Verhaar,&nbsp;K. Schram","doi":"10.1016/0031-8914(74)90320-6","DOIUrl":"https://doi.org/10.1016/0031-8914(74)90320-6","url":null,"abstract":"<div><p>An expression is derived for the Van der Waals force between two semi-infinite bodies with small surface irregularities. Calculations are given both for the plane-plane and the plane-sphere configuration. The value of the correction from the surface irregularities upon the Van der Waals force is shown to amount easily to 10–50%.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"78 1","pages":"Pages 187-190"},"PeriodicalIF":0.0,"publicationDate":"1974-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90320-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91725732","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: 53
On the single-site theory of electric conductivity in some disordered systems 一些无序系统中电导率的单点理论
Physica Pub Date : 1974-11-15 DOI: 10.1016/0031-8914(74)90312-7
J. Popielawski
{"title":"On the single-site theory of electric conductivity in some disordered systems","authors":"J. Popielawski","doi":"10.1016/0031-8914(74)90312-7","DOIUrl":"https://doi.org/10.1016/0031-8914(74)90312-7","url":null,"abstract":"<div><p>The Yonezawa diagrammatic method has been generalized in order to describe the electric conductivity both in compositionally disordered systems (substitution alloys) and translationally disordered systems with short-range correlations (liquid metals). Results equivalent to those by Velicky and Leath have been obtained in the case of substitutional alloys. A generalized resistivity formula has been derived for liquid metals with the approximation of a long mean free path of conducting electrons. In the case of weak scattering potential this formula can be reduced to the Ziman expression. This formula includes also, as an approximiation, the result of the Ashcroft-Schaich theory. An important role of the special expression of high-order atomic correlations in liquid metals by pair correlations is pointed out. New integral equations determining the pair correlation function in fluids are suggested on the basis of this expression.</p></div>","PeriodicalId":55605,"journal":{"name":"Physica","volume":"78 1","pages":"Pages 97-112"},"PeriodicalIF":0.0,"publicationDate":"1974-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0031-8914(74)90312-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91759688","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: 16
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