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The definition of local spatial densities by using sharply localized one-particle states is applied to spin-3/2 systems. Matrix elements of the electromagnetic current and the energy-momentum tensor are considered and integral expressions…

High Energy Physics - Phenomenology · Physics 2023-02-22 H. Alharazin , B. -D. Sun , E. Epelbaum , J. Gegelia , U. -G. Meißner

The recently proposed Wigner function for a particle in an infinite lattice [NJP 14, 103009 (2012)] is extended here to include an internal degree of freedom, as spin. The formalism is developed to account for dynamical processes, with or…

Quantum Physics · Physics 2015-01-26 M. Hinarejos , M. C. Bañuls , A. Pérez

We present a new quasi-probability distribution function for ensembles of spin-half particles or qubits that has many properties in common with Wigner's original function for systems of continuous variables. We show that this function…

Quantum Physics · Physics 2013-03-04 Derek Harland , M. J. Everitt , Kae Nemoto , T. Tilma , T. P. Spiller

An introduction to spin techniques in particle physics is given. Among the topics covered are: helicity formalism and its applications to the decay and scattering of spin-1/2 and spin-1 particles, techniques for evaluating helicity…

High Energy Physics - Phenomenology · Physics 2009-09-25 Howard E. Haber

We show that, in ideal-spin hydrodynamics, the components of the spin tensor follow damped wave equations. The damping rate is related to nonlocal collisions of the particles in the fluid, which enter at first order in $\hbar$ in a…

Nuclear Theory · Physics 2025-02-10 David Wagner , Masoud Shokri , Dirk H. Rischke

With the help of a semi-classical kinetic theory, a new collision kernel is proposed, which simultaneously conserves the energy-momentum tensor and the spin tensor of a relativistic fluid of spin-1/2 particles irrespective of the frame and…

High Energy Physics - Phenomenology · Physics 2025-03-12 Samapan Bhadury

Generalized thermodynamic relations are introduced into the framework of a relativistic perfect spin hydrodynamics. They allow for consistent treatment of spin degrees of freedom, including the use of spin tensors whose structure follows…

High Energy Physics - Phenomenology · Physics 2024-07-09 Wojciech Florkowski , Mykhailo Hontarenko

Using the complete orthonormal sets of radial parts of nonrelativitistic exponential type orbitals (2,1, 0, 1, 2, ...) and spinor type tensor spherical harmonics of rank s the new formulae for the 2(2s+1)-component relativistic spinors…

Mathematical Physics · Physics 2015-03-13 I. I. Guseinov

The description of particles with spin can be attained by using a spin density matrix in high energy reaction. In this paper we present a parametrization of the spin density matrix for spin -3/2 particles in the Cartesian form. Comparing…

High Energy Physics - Phenomenology · Physics 2020-05-05 Jiao Jiao Song , Wan Ling Chang

We show that Wigner's infinite spin particle classically is described by a reparametrization invariant higher order geometrical Lagrangian. The model exhibit unconventional features like tachyonic behaviour and momenta proportional to…

High Energy Physics - Theory · Physics 2009-11-11 Ludde Edgren , Robert Marnelius , Per Salomonson

We establish covariant semiclassical transport equations of massive spin-1/2 particles which are generated by the quantum kinetic equation modified by enthalpy current dependent terms. The purpose of modification is to take into account the…

High Energy Physics - Theory · Physics 2020-08-26 O. F. Dayi , E. Kilincarslan

We revisit the derivation of the nonlocal collision term in the Boltzmann equation for spin-1/2 particles, using both the Wigner-function approach by de Groot, van Leeuwen, and van Weert, and the Kadanoff-Baym equation in $T$-matrix…

Nuclear Theory · Physics 2023-01-11 David Wagner , Nora Weickgenannt , Dirk H. Rischke

We derive expressions for the vector and tensor components of the spin polarization of massive vector bosons at local thermodynamic equilibrium up to second order in the space-time gradients of the thermodynamic fields pertaining to the…

High Energy Physics - Phenomenology · Physics 2025-07-24 Zhong-Hua Zhang , Xu-Guang Huang , Francesco Becattini , Xin-Li Sheng

We present a new interpretation for reduced density matrices of secondary variables in relativistic systems via an analysis of Wigner's method to construct the irreducible unitary representations of the Poincar\'e group. We argue that the…

Quantum Physics · Physics 2015-06-17 E. R. F. Taillebois , A. T. Avelar

A new spinning particle with a definite sign of the energy is defined on spacelike hypersurfaces after a critical discussion of the standard spinning particles. They are the pseudoclassical basis of the positive energy $({1\over 2},0)$ [or…

High Energy Physics - Theory · Physics 2009-10-31 F. Bigazzi , L. Lusanna

Starting from kinetic theory description of massive spin-1/2 particles in presence of magnetic field, equations for relativistic dissipative non-resistive magnetohydrodynamics are obtained in the small polarization limit. We use a…

We present a quantum kinetic theory for spin-$1/2$ particles, including the spin-orbit interaction, retaining particle dispersive effects to all orders in $\hbar$, based on a gauge-invariant Wigner transformation. Compared to previous…

Plasma Physics · Physics 2023-02-23 Robin Ekman , Haidar Al-Naseri , Jens Zamanian , Gert Brodin

The effect of a classical gravitational field on the spin entanglement of a system of two spin-1/2 particles moving in the curved spacetime is discussed. The system is described by a two-particle Gaussian wave packet represented in the…

Quantum Physics · Physics 2010-10-26 Bahram Nasr Esfahani

The energy momentum tensor of perfect fluid is a simplified but successful model in astrophysics. In this paper, assuming the particles driven by gravity and moving along geodesics, we derived the functions of state in detail. The results…

General Physics · Physics 2017-10-31 Ying-Qiu Gu

We investigate the non-equilibrium dynamics of a one-dimensional spin-1/2 XXZ model at zero-temperature in the regime $|\Delta|< 1$, initially prepared in a product state with two domain walls i.e,…

Statistical Mechanics · Physics 2023-02-21 Stefano Scopa , Pasquale Calabrese , Jérôme Dubail