Related papers: The Most Negative and the Most Positive Value of t…
We find the most negative and most positive values of the spin operator for a system of several nucleons. We us an ls basis to make the analysis.
Using the LS coupling we find the most positive and negative values of the spin operator sigma.These theoretical limits are much wider than the "empirical" single particle limits.A comparison of the Nilsson and Schmidt models is made for…
We find the largest negative value of the expectation of the spin operator for a many nucleon system.
It is considered how spin-orbit potential for two nucleons is changed when one of them is imbedded in nuclear matter. It is emphasized that there appears new tipe of potential antisymmetric under nucleon spins which is proportional to mass…
The notion of the spin is shown to have two constituents, as exemplified by the spin of the electron. The first one is related to the form of the wave equation and determines the fermion or boson particle type. This implies the spin taking…
We consider some multivariate rational functions which have (or are conjectured to have) only positive coefficients in their series expansion. We consider an operator that preserves positivity of series coefficients, and apply the inverse…
Entanglement is studied in the framework of Dyson's S-matrix theory in relativistic quantum field theory, which leads to a natural definition of entangled states of a particle-antiparticle pair and the spin operator from a Noether current.…
It is well known that positive Green's operators are not necessarily positivity preserving. In this paper we investigate the matter of just how far from being positivity preserving a positive Green's operator can be. We will also identify a…
In the Skyrme model of nucleons and nuclei, the spin excitation energy of the nucleon is traditionally calculated by a fit of the rigid rotor quantization of spin/isospin of the fundamental Skyrmion (the hedgehog) to the masses of the…
An operatorial model of a system made by $N$ agents interacting each other with mechanisms that can be thought of as cooperative or competitive is presented. We associate to each agent an annihilation, creation and number fermionic…
Deep inelastic structure functions for the nucleon are obtained in a constituent quark model on the light cone. Parton model formulas are derived. The negative slope of $F_{2}^{n}/F_{2}^{p} requires attraction between scalar quark pairs.…
Weak values of the spin operator Sz of massive particles, more precisely neutrons, have been experimentally determined by applying a novel measurement scheme. This is achieved by coupling the neutron's spin weakly to its spatial degree of…
The nucleon spin problem raises experimental and theoretical questions regarding the contribution of the orbital angular momentum of the quarks to the total spin of the nucleon. In this article we examine the commutation relationships of…
In this brief article we discuss spin polarization operators and spin polarization states of 2+1 massive Dirac fermions and find a convenient representation by the help of 4-spinors for their description. We stress that in particular the…
We use a simple field theory model to investigate the role of the nucleon spin for the magnetic sum rules associated with the low-lying collective scissors mode in deformed nuclei. Various constraints from rotational symmetry are elucidated…
We find all spin operators for a Dirac particle satisfying the following very general conditions: (i) spin does not convert positive (negative) energy states into negative (positive) energy states, (ii) spin is a pseudo-vector, and (iii)…
We have limited our interaction scope to those involving particle-s spin. We then develop operators for handling a many-body treatment of the spin interactions. The results presented show how to promote the particles of the system into the…
Positivity reduces substantially the allowed domain for spin observables. We briefly recall some methods used to determine these domains and give some typical examples for exclusive and inclusive spin-dependent reactions.
A relativistic spin operator is to be the difference between the total and orbital angular momentum. As the unique position operator for a localized state, the remarkable Newton-Wigner position operator, which has all desirable commutation…
We explore a spin-fermion model with fermion-spin-quadrupolar interaction. In a nematic phase, this interaction reduces to a four-fermion interaction that is a basis of superconductivity. When the coupling constant is positive the…