On a class of equilibrium states under the Kubo-Martin-Schwinger boundary condition

Using the Kubo-Martin-Schwinger boundary condition for equilibrium states of quantum statistical mechanics of fermion gas, we prove that forT;0 a one-particle evolution (corresponding essentially to bilinear hamiltonians) generally defines a unique equilibrium state, which is quasi-free. Conversely any quasi-free state is the equilibrium state for a single one-particle evolution if it has no Fock part in its product decomposition. Limiting cases whereT 0 andT are studied. In the case whereT 0 one shows that the state generally converges to a Fock state linked to the evolution.Attaché de Recherche au C.N.R.S.This work is a part of a Thèse de Doctorat d'Etat presented to the Faculté des Sciences de Marseille, April 23, 1969, under the number A.O. 3073.     

ГАЛЬВАНОМАГНИТНЫЙ Э ФФЕКТ В ОБЛАСТИ ТЕМПЕРАТУРЫ КЮРИ

. - II- . .     

Рентгенографически е измерения остаточн ыгх напряжений в керамич еских изоляторах из плавленного корун да

Al₂O₃ K ₁ . , , .     

Beam Optics and Signal Analysis in a Quantumlike Approach

The application of the tomographic map introduced recently in quantum mechanics is discussed in connection with classical problems that are described by equations formally coinciding with the equations of quantum theory. Examples of the classical problems such as chargedparticlebeam transport and analyticsignal analysis are reviewed. Some aspects of possible applications in quantum computing and quantum communication are discussed.     

Differential calculus on quantum spheres

Three-dimensional differential calculus on quantum spheres S _infc ^sup2 ,]–1, 1[{0}, c[0, ], is introduced and investigated. Spectra of generalized Laplacians are found. These operators are expressed by generalized directional derivatives. Classical limits of these objects are obtained and a simple approach to quantum mechanics on a quantum sphere is presented.     

О ВЛИЯНИИ НАПЯЖЕНИЯ, ВОЗНИКАЮЩЕГО ПРИ ПРЕ ЦИПИТАЦИИ, НА КОЭРЦИТ ИВНУЮ СИЛУ ФЕРРОМАГНЕТИКО В

, . - , m. . . , , , . , , Fe₃C .     

Hidden variables with directionalization

A hidden-variables model is presented which, by using a hypothesis of directionalization of the photons at the deflectors, is able to reproduce all the quantum mechanical predictions for the Orsay realization of the Einstein-Podolsky-Rosen-Bohm experiment, even for ideal polarizers, detectors, time-coincidence windows, and event-ready setups. The model also holds for the no-enhancement assumption. The requirements for an experiment aimed to discriminate between quantum mechanics and the new model are discussed. Under some plausible assumptions, such experiment is achievable with the current technology. It would be essentially a remake of the Orsay one with improved deflectors and a time-resolved measurement of the photon flows toward each detector.     

Relativistic Quantum Mechanics as a Telegraph

A derivation by Fröhner of non-relativistic quantum mechanics via Fourier analysis applied to probability theory is not extendable to relativistic quantum mechanics because Schrödinger's positive definite probability density * is lost (Dirac's spin 1/2 case being the exception). The nature of the Fourier link then changes; it points to a redefinition of the probability scheme as an information carrying telegraph, the code of which is Born's as extended by Dirac and by Feynman. Hermitian symmetry of the transition amplitude between Dirac representations expresses reciprocity of preparation and measurement (the quantal coding and decoding), two equally active interventions of the physicist; as the measurement perturbs the system retrodiction implies retroaction evidenced in delayed choice. Reciprocity of knowledge and organization vindicates Wigner's claim that reciprocal to the action of matter upon mind there exists a direct action of mind upon matter: psychokinesis, branded by Jaynes as a psychiatric disorder of the Copenhagen school. As for factlike irreversibility, it is expressed by the enormity of the change rate from information to negentropy: while gain in knowledge is normal psychokinesis is paranormal. Stapp's recent discussion of psychokinesis in a quantum context should be resumed in association with an EPR correlation; an experimental test is proposed.     

Notes on the classical and the nonrelativistic limits in quantum mechanics

A method is presented which can be used to discuss both the classical and also the nonrelativistic limit of quantum mechanics. A one-to-one correspondence may be established between the asymptotic convergence of the resolvent and that of the timedependent solution. In so far as the question of dynamics is concerned we investigate the relation between families of nonrelativistic Hamiltonians and the corresponding Dirac-Hamiltonians when c± or when c±0. The nonrelativistic free theory formally shows the same pattern when ±0 (the classical limit) or when ±. The investigation finally shows how the asymptotic convergence of the relativistic theory can take place under some fairly general conditions of the radiation field.     

Photo-piezoelectric effect in semiconductors

A new photo-voltaic effect was observed which is caused by inhomogeneous distribution of the pressure in a semiconductor. Its production can be explained by the dependence of the energy gap on the pressure.

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, . .

     

Relative coarse-graining

The problem of statistical inference based on a partial measurement (coarse-graining) requires the specification of an a priori distribution. We reformulate the ordinary theory such as to encompass systematically a wide range of a priori distributions (relative coarse-graining). This is done in a mathematical setting which admits an interpretation in both classical probability and quantum mechanics. The formalism is illustrated in a few simple examples, such as the die whose geometrical shape is known, the spin in thermal equilibrium with an unknown reservoir, and the position measurement of a one-dimensional particle. It is shown that some of the limitations of the usual theory are a consequence of the fact that it is restricted to equidistributed (symmetric) a priori states.     

Real-time green's functions in many body problems

It is shown that the superoperators acting on the Liouville space of a system of fermions (bosons) with a given number of degrees of freedom form an algebra which corresponds to that of a system of superfermions (superbosons) with a doubled number of degrees of freedom. Discussed are different reformulations of quantum statistical mechanics in terms of the superparticles and their relationship to the time-path technique and to thermo field dynamics. The classical analogue of the superoperator formulation is shown to coincide with the Martin Siggia Rose formalism.     

The non-relativistic limit ofP(ϕ)2 quantum field theories: Two-particle phenomena

It is proved that for two-particle phenomena theP()₂ quantum field theories with speed of lightc converge to non-relativistic quantum mechanics with a function potential in the limitc.Supported by NSF Grant No. PHY 7506746     

Mean field theory for Coulomb systems

We study a classical charge symmetric system with an external charge distributionq in three dimensions in the limit that the plasma parameter zero. We prove that ifq is scaled appropriately then the correlation functions converge pointwise to those of an ideal gas in the external mean field(x) where is given by-+ 2z sinh() =q This is the mean field equation of Debye and Hückel. The proof uses the sine-Gordon transformation, the Mayer expansion, and a correlation inequality.Work partially supported by NSF Grant MCS 82-02115.     

Time reversal in classical and quantum mechanics

A review of Wigner's time reversal is presented and some important aspects are emphasized. The subject is introduced via classical mechanics. Non-physical statements as time running backwards are avoided. Comments are made on the roles of time and of the operatori(/t) in quantum mechanics. The role of symmetries and conservation laws and some properties of the time-reversed states are discussed.Work supported by Instituto Nacional de Investigação Científica, Portugal.     

The nonrelativistic Schrödinger equation in “quasi-classical” theory

The author has recently proposed a quasi-classical theory of particles and interactions in which particles are pictured as extended periodic disturbances in a universal field (x, t), interacting with each other via nonlinearity in the equation of motion for . The present paper explores the relationship of this theory to nonrelativistic quantum mechanics; as a first step, it is shown how it is possible to construct from a configuration-space wave function (x ₁,x ₂,t), and that the theory requires that satisfy the two-particle Schrödinger equation in the case where the two particles are well separated from each other. This suggests that the multiparticle Schrödinger equation can be obtained as a direct consequence of the quasi-classical theory without any use of the usual formalism (Hilbert space, quantization rules, etc.) of conventional quantum theory and in particular without using the classical canonical treatment of a system as a crutch theory which has subsequently to be quantized. The quasi-classical theory also suggests the existence of a preferred absolute gauge for the electromagnetic potentials.     

Some applications of the discrete fourier transform to problems of crystal lattice deformation I

The theory of the discrete Fourier transform [1], [2] is applied in solving a system of difference equations describing the positions of atoms in a deformed crystal lattice. The crystal lattice is approximated by the Born-Kármán model modified to include the internal energy of the undeformed crystal.

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, , , [1] [2]. - , , .

     

Independence of automorphism group,center, and state space of quantum logics

We prove that quantum logics (=orthomodular posets) admit full independence of the attributes important within the foundations of quantum mechanics. Namely, we present the construction of quantum logics with given sublogics (=physical subsystems), automorphism groups, centers (=classical parts of the systems), and state spaces. Thus, all these parameters are independent. Our result is rooted in the line of investigation carried out by Greechie; Kallus and Trnková; Kalmbach; and Navara and Pták; and considerably enriches the known algebraic methods in orthomodular posets.     

Anisotropy of the low temperature resistivity of hexagonal single crystalline spin glass systems

The impurity contribution to the resistivity in zero field (T) of dilute hexagonal single crystals of ZnMn, CdMn and MgMn has been studied in the mK range on samples cut parallel () and perpendicular () to thec-axis, using a SQUID technique for the measurements. Typical spin glass behavior is found in (T) as well as (T) for all alloys, with Kondo like logarithmic increases at higher temperatures and maxima atT _m at lower temperatures, indicating the influence of impurity interactions. The differences in the corresponding isotropic resistivity _poly(T) between the three systems can qualitatively be understood within the framework of a theoretical model by Larsen, describing (T) as a function of universal quantitiesT/T _K and _RKKY/T _K , where _RKKY is the RKKY-interaction strength andT _K the Kondo temperature. With respect to the two lattice directions studied, the behavior of (T and (T is anisotropic in the Kondo regime as well as in the range where ordering becomes important. While the anisotropy in the Kondo slope can be understood by an anisotropic unitarity limit, the understanding of the anisotropy in region where impurity interactions are important remains problematic.Dedicated to Prof. Dr. S. Methfessel on the occasion of his 60th birthday     

The inside observer in quantum mechanics

The observer in physics has always referred to someone who stands on the outside of a system looking in. In this paper an inside observer is defined, and an experiment is proposed that tests a given formulation of the problem of measurement in quantum mechanics.