123621331
APPROACH TO THE NUCLEAR MANY-BODY PROBLEM BY VARIATIONALLY DETERMINED TRANSFORMATION. II.
We present a generalization of the Hartree-Fock (HF) method incorporating two-body correlations. The correlations are introduced by means of a unitary operator ${e}^{\mathrm{iF}}$, where $F$ is a Hermitian one- and two-body operator to be determined by the variational principle. Assuming that the matrix elements of $F$ are small so that powers of $F$ higher than the second may be neglected, a set of linear equations determining $F$ is obtained. The relation between our method and methods used to treat singular interactions is discussed. The method is applied to two recently suggested models and is compared with the HF method, second-order perturbation theory, and with the random-phase approximation. It is found that our method yields very good results within the range of validity of our approximations, which seems to call forth applications to more realistic problems. Possible applications to the study of collective phenomena in nuclei are indicated.
122236095
APPROACH TO THE NUCLEAR MANY-BODY PROBLEM BY A VARIATIONALLY DETERMINED TRANSFORMATION.
120768053
Dips in one-pion production processes from a statistical point of view
122704344
Mesonic structure in the nucleon
118409646
Superfluidity of hadronic matter
SummaryThe mesons in the nucleon are associated with a Bose system with an energy excitation spectrum ε(p), wherep is the corresponding momentum. This spectrum can be investigated by studying the nucleon recoil in one-meson production processes. It turns out that
$$\mathop {\lim }\limits_{p \to 0} (\varepsilon /p) \ne 0$$
. This is the Landau criterion for superfluidity. Herefrom we infer that hadronic matter is superfluid. Possible manifestations of this phenomenon in strong interactions are a bootstrap relation between the masses of mesonic and baryonic resonances, the shift of the δ-resonance in nuclei, the existence of a maximum resonance mass equivalent to an ionization point and the existence of a critical temperature of hadronic matter instead of a maximum temperature.RiassuntoI mesoni nel nucleone sono associati per mezzo di un sistema di bose con uno spettro di energie di eccitazione ε(p), dovep è l'impulso corrispondente. Si può analizzare questo spettro studiando il rinculo del nucleone nei processi di produzione di un mesone. Risulta che
$$\mathop {\lim }\limits_{p \to 0} (\varepsilon /p) \ne 0$$
. Questo è il criterio di landau per la superfluidità. Da ciò si inferisce che la materia adronica è superfluida. Possibili manifestazioni di questo fenomeno nelle interazioni forti sono una relazione di bootstrap fra le masse delle risonanze mesoniche e barioniche, lo spostamento della risonanza δ nei nuclei, l'esistenza di una massa massima della risonanza equivalente ad un punto di ionizzazione e l'esistenza di una temperatura critica della materia adronica invece di una temperatura massima.РезюмеМезоны в нуклоне связываутся с Гозе-системой с энергетическим спектром возбуждения ε(p), гдеp есть соответствующии импульс. Этот спектр может быть исследован посредством изучения отдачи нуклона в процессе рождения одного пиона. Оказывается, что
$$\mathop {\lim }\limits_{p \to 0} (\varepsilon /p) \ne 0$$
. Это представляет критерий Ландау для сверхтекучести, из которого мы делаем вывод, что адронное вещество является сверхтекучим. Возможные проявления этого явления в сильных взаимодействиях представляют: соотношения бутстрепа между массами мезонных и барионных резонансов, сдвиг δ резонанса в ядрах, существование резонансной массы, эквивалентной точке ионизации, и существование критической температуры адронного вещества вместо максимальной темпатуры.
119035534
A New Measurement of High Energy Neutrino and Antineutrino Total Cross Sections
20903628
Repulsive Casimir forces.
We discuss repulsive Casimir forces between dielectric materials with nontrivial magnetic susceptibility. It is shown that considerations based on the naive pairwise summation of van der Waals and Casimir-Polder forces may not only give an incorrect estimate of the magnitude of the total Casimir force but even the wrong sign of the force when materials with high dielectric and magnetic responses are involved. Indeed repulsive Casimir forces may be found in a large range of parameters, and we suggest that the effect may be realized in known materials. The phenomenon of repulsive Casimir forces may be of importance both for experimental study and for nanomachinery applications.
126319381
Invariant Mass Distributions as Evidence for New Particle Production by High-Energy anti-neutrinos
119995096
Coherent and thermal coherent state
The characterization of coherent states as the quantum states that split into two uncorrelated beams is considered. The characterization leads to the study of coherent states at finite temperature—thermal coherent states (TCS’s). These TCS’s are defined within the formalism of thermo field dynamics (TFD). TFD allows a generalization of the uncertainty relation that accounts for both thermal and quantum fluctuations. The TCS is shown to be a minimal state for the generalized uncertainty relation.
53454093
Phase-space formulation of quantum mechanics and quantum-state reconstruction for physical systems with Lie-group symmetries
We present a detailed discussion of a general theory of phase-space distributions, introduced recently by the authors @J. Phys. A 31 ,L 9 ~1998!#. This theory provides a unified phase-space formulation of quantum mechanics for physical systems possessing Lie-group symmetries. The concept of generalized coherent states and the method of harmonic analysis are used to construct explicitly a family of phase-space functions which are postulated to satisfy the Stratonovich-Weyl correspondence with a generalized tracing condition. The symbol calculus for the phase-space functions is given by means of the generalized twisted product. The phase-space formalism is used to study the problem of the reconstruction of quantum states. In particular, we consider the reconstruction method based on measurements of displaced projectors, which comprises a number of recently proposed quantum-optical schemes and is also related to the standard methods of signal processing. A general group-theoretic description of this method is developed using the technique of harmonic expansions on the phase space. @S1050-2947~99!00702-7#