On the relativistic spin projection operators

1993 ◽  
Vol 43 (8) ◽  
pp. 777-782
Author(s):  
M. Bednář ◽  
P. Kolář
Keyword(s):  
Spin Projection ◽  
Projection Operators ◽  
Relativistic Spin

scholarly journals Extending the spin projection operators for gravity models with parity-breaking in 3-D

2010 ◽  
Vol 374 (34) ◽  
pp. 3410-3415 ◽  
Author(s):  
C.A. Hernaski ◽  
B. Pereira-Dias ◽  
A.A. Vargas-Paredes
Keyword(s):  
Gravity Models ◽  
Spin Projection ◽  
Projection Operators ◽  
Parity Breaking

scholarly journals Unitarity of Singh-Hagen Model in D Dimensions

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Elias L. Mendonça ◽  
R. Schimidt Bittencourt
Keyword(s):  
General Expression ◽  
Spin Projection ◽  
Projection Operators ◽  
Source Terms ◽  
Particle Content ◽  
Complete Set

The particle content of the Singh-Hagen model (SH) in D dimensions is revisited. We suggest a complete set of spin-projection operators acting on totally symmetric rank-3 fields. We give a general expression for the propagator and determine the coefficients of the SH model confirming previous results of the literature. Adding source terms, we provide a unitarity analysis in D dimensions. In addition, we have also analyzed the positivity of the massless Hamiltonian.

scholarly journals Higher derivative fermionic field equation in the first-orderformalism

2007 ◽  
Vol 85 (8) ◽  
pp. 887-897 ◽  
Author(s):  
S I Kruglov
Keyword(s):  
Dirac Equation ◽  
Spin Projection ◽  
Electromagnetic Current ◽  
Pure Spin ◽  
Projection Operators ◽  
Third Order ◽  
First Order ◽  
Generalized Dirac Equation ◽  
Electromagnetic Interactions ◽  
Higher Derivative

The generalized Dirac equation of the third order, describing particles with spin 1/2 and three mass states, is analyzed. We obtain the first-order generalized Dirac equation in the 24-dimensional matrix form. The mass and spin projection operators are found that extract solutions of the wave equation corresponding to pure spin states of particles. The density of the electromagnetic current is obtained, and minimal and nonminimal(anomalous) electromagnetic interactions of fermions are considered by introducing three phenomenological parameters. The Hamiltonian form of the first-order equation is obtained.PACS Nos.: 03.65.Pm, 11.10.Ef; 12.10.Kt

scholarly journals Hamiltonian analysis and positivity of a newmassive spin-2 model

2021 ◽  
Author(s):  
Alessandro Luiz Ribeiro dos Santos ◽  
Denis Dalmazi ◽  
Wayne Leonardo Silva de Paula
Keyword(s):  
Correlation Functions ◽  
Degrees Of Freedom ◽  
Spin Projection ◽  
Projection Operators ◽  
Gauge Invariant ◽  
New Model ◽  
Mixed Symmetry ◽  
Massive Spin ◽  
Rank 2 ◽  
Hamiltonian Analysis

Abstract Recently a new model has been proposed to describe free massive spin-2 particles in D dimensions in terms of a non symmetric rank-2 tensor eµν and a mixed symmetry tensor Bµ[αβ]. The model is invariant under linearized diffeomorphisms without Stueckelberg fields. It resembles a spin-2 version of the topologically massive spin-1 BF model (Cremmer-Scherk model). Here we apply the Dirac-Bergmann procedure in order to identify all Hamiltonian constraints and perform a complete counting of degrees of freedom. In D = 3 + 1 we find 5 degrees of freedom corresponding to helicities ±2, ±1, 0 as expected. The positivity of the reduced Hamiltonian is proved by using spin projection operators. We have also proposed a parent action that establishes the duality between the Fierz-Pauli and the new model. The equivalence between gauge invariant correlation functions of both theories is demonstrated.

scholarly journals Spin projection operators in (A)dS and partial masslessness

2020 ◽  
Vol 800 ◽  
pp. 135128
Author(s):  
Sergei M. Kuzenko ◽  
Michael Ponds
Keyword(s):  
Spin Projection ◽  
Projection Operators

scholarly journals New class of spin projection operators for 3D models

2012 ◽  
Vol 86 (10) ◽  
Author(s):  
Antonio Accioly ◽  
José Helayël-Neto ◽  
Bruno Pereira-Dias ◽  
Carlos Hernaski
Keyword(s):  
3D Models ◽  
Spin Projection ◽  
Projection Operators ◽  
New Class

scholarly journals Spin projection operators and higher-spin Cotton tensors in three dimensions

2019 ◽  
Vol 790 ◽  
pp. 389-395 ◽  
Author(s):  
Evgeny I. Buchbinder ◽  
Sergei M. Kuzenko ◽  
James La Fontaine ◽  
Michael Ponds
Keyword(s):  
Three Dimensions ◽  
Spin Projection ◽  
Projection Operators ◽  
Higher Spin

Assessing the Calculation of Exchange Coupling Constants and Spin Crossover Gaps Using the Approximate Projection Model to Improve Density Function Calculations

2019 ◽  
Author(s):  
Xianghai Sheng ◽  
Lee Thompson ◽  
Hrant Hratchian
Keyword(s):  
Density Functional Theory ◽  
Exchange Coupling ◽  
Density Functional ◽  
Spin Crossover ◽  
Coupling Constants ◽  
Spin Projection ◽  
Coupling Constant ◽  
Projection Model ◽  
Functional Theory

This work evaluates the quality of exchange coupling constant and spin crossover gap calculations using density functional theory corrected by the Approximate Projection model. Results show that improvements using the Approximate Projection model range from modest to significant. This study demonstrates that, at least for the class of systems examined here, spin-projection generally improves the quality of density functional theory calculations of J-coupling constants and spin crossover gaps. Furthermore, it is shown that spin-projection can be important for both geometry optimization and energy evaluations. The Approximate Project model provides an affordable and practical approach for effectively correcting spin-contamination errors in molecular exchange coupling constant and spin crossover gap calculations.

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