121 research outputs found

    Quarks in the Skyrme-'t Hooft-Witten Model

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    The three-flavor Skyrme-'t Hooft-Witten model is interpreted in terms of a quark-like substructure, leading to a new model of explicitly confined color-free ``quarks'' reminiscent of Gell-Mann's original pre-color quarks, but with unexpected and significant differences.Comment: Latex, 6 pages, no figure

    New relations and identities for generalized hypergeometric coefficients

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    AbstractGeneralized hypergeometric coefficients 〈pFq(a; b)¦λ〉 enter into the problem of constructing matrix elements of tensor operators in the unitary groups and are the expansion coefficients of a multivariable symmetric function generalization pFq(a; b; z), z = (z1, z2,…, zt), of the Gauss hypergeometric function in terms of the Schur functions eλ(z), where λ = (λ1, λ2,…, λt) is an arbitrary partition. As befits their group-theoretic origin, identities for these generalized hypergeometric coefficients characteristically involve series summed over the Littlewood-Richardson numbers g(μνλ). Identities that may be interpreted as generalizations of the Bailey, Saalschütz,… identities are developed in this paper. Of particular interest is an identity which develops in a natural way a group-theoretically defined expansion over new inhomogeneous symmetric functions. While the relations obtained here are essential for the development of the properties of tensor operators, they are also of interest from the viewpoint of special functions

    Degeneracies when T=0 Two Body Matrix Elements are Set Equal to Zero and Regge's 6j Symmetry Relations

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    The effects of setting all T=0 two body interaction matrix elements equal to a constant (or zero) in shell model calculations (designated as =0=0) are investigated. Despite the apparent severity of such a procedure, one gets fairly reasonable spectra. We find that using =0=0 in single j shell calculations degeneracies appear e.g. the I=1/2−I={1/2} ^{-} and 13/2−{13/2}^{-} states in 43^{43}Sc are at the same excitation energies; likewise the I=32+3_{2}^{+},72+7_{2}^{+},91+^{+}_{1} and 101+^{+}_{1} states in 44^{44}Ti. The above degeneracies involve the vanishing of certain 6j and 9j symbols. The symmetry relations of Regge are used to explain why these vanishings are not accidental. Thus for these states the actual deviation from degeneracy are good indicators of the effects of the T=0 matrix elements. A further indicator of the effects of the T=0 interaction in an even - even nucleus is to compare the energies of states with odd angular momentum with those that are even

    Generalized quantum field theory: perturbative computation and perspectives

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    We analyze some consequences of two possible interpretations of the action of the ladder operators emerging from generalized Heisenberg algebras in the framework of the second quantized formalism. Within the first interpretation we construct a quantum field theory that creates at any space-time point particles described by a q-deformed Heisenberg algebra and we compute the propagator and a specific first order scattering process. Concerning the second one, we draw attention to the possibility of constructing this theory where each state of a generalized Heisenberg algebra is interpreted as a particle with different mass.Comment: 19 page

    Wilson function transforms related to Racah coefficients

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    The irreducible ∗*-representations of the Lie algebra su(1,1)su(1,1) consist of discrete series representations, principal unitary series and complementary series. We calculate Racah coefficients for tensor product representations that consist of at least two discrete series representations. We use the explicit expressions for the Clebsch-Gordan coefficients as hypergeometric functions to find explicit expressions for the Racah coefficients. The Racah coefficients are Wilson polynomials and Wilson functions. This leads to natural interpretations of the Wilson function transforms. As an application several sum and integral identities are obtained involving Wilson polynomials and Wilson functions. We also compute Racah coefficients for U_q(\su(1,1)), which turn out to be Askey-Wilson functions and Askey-Wilson polynomials.Comment: 48 page

    Recurrence and differential relations for spherical spinors

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    We present a comprehensive table of recurrence and differential relations obeyed by spin one-half spherical spinors (spinor spherical harmonics) Ωκμ(n)\Omega_{\kappa\mu}(\mathbf{n}) used in relativistic atomic, molecular, and solid state physics, as well as in relativistic quantum chemistry. First, we list finite expansions in the spherical spinor basis of the expressions A⋅B Ωκμ(n)\mathbf{A}\cdot\mathbf{B}\,\Omega_{\kappa\mu}(\mathbf{n}) and {A⋅(B×C) Ωκμ(n)\mathbf{A}\cdot(\mathbf{B}\times\mathbf{C})\, \Omega_{\kappa\mu}(\mathbf{n})}, where A\mathbf{A}, B\mathbf{B}, and C\mathbf{C} are either of the following vectors or vector operators: n=r/r\mathbf{n}=\mathbf{r}/r (the radial unit vector), e0\mathbf{e}_{0}, e±1\mathbf{e}_{\pm1} (the spherical, or cyclic, versors), σ\boldsymbol{\sigma} (the 2×22\times2 Pauli matrix vector), L^=−ir×∇I\hat{\mathbf{L}}=-i\mathbf{r}\times\boldsymbol{\nabla}I (the dimensionless orbital angular momentum operator; II is the 2×22\times2 unit matrix), J^=L^+1/2σ\hat{\mathbf{J}}=\hat{\mathbf{L}}+1/2\boldsymbol{\sigma} (the dimensionless total angular momentum operator). Then, we list finite expansions in the spherical spinor basis of the expressions A⋅B F(r)Ωκμ(n)\mathbf{A}\cdot\mathbf{B}\,F(r)\Omega_{\kappa\mu}(\mathbf{n}) and A⋅(B×C) F(r)Ωκμ(n)\mathbf{A}\cdot(\mathbf{B}\times\mathbf{C})\, F(r)\Omega_{\kappa\mu}(\mathbf{n}), where at least one of the objects A\mathbf{A}, B\mathbf{B}, C\mathbf{C} is the nabla operator ∇\boldsymbol{\nabla}, while the remaining ones are chosen from the set n\mathbf{n}, e0\mathbf{e}_{0}, e±1\mathbf{e}_{\pm1}, σ\boldsymbol{\sigma}, L^\hat{\mathbf{L}}, J^\hat{\mathbf{J}}.Comment: LaTeX, 12 page

    Characterization of the Positivity of the Density Matrix in Terms of the Coherence Vector Representation

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    A parameterization of the density operator, a coherence vector representation, which uses a basis of orthogonal, traceless, Hermitian matrices is discussed. Using this parameterization we find the region of permissible vectors which represent a density operator. The inequalities which specify the region are shown to involve the Casimir invariants of the group. In particular cases, this allows the determination of degeneracies in the spectrum of the operator. The identification of the Casimir invariants also provides a method of constructing quantities which are invariant under {\it local} unitary operations. Several examples are given which illustrate the constraints provided by the positivity requirements and the utility of the coherence vector parameterization.Comment: significantly rewritten and submitted for publicatio

    Dirac operator on the q-deformed Fuzzy sphere and Its spectrum

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    The q-deformed fuzzy sphere SqF2(N)S_{qF}^2(N) is the algebra of (N+1)×(N+1)(N+1)\times(N+1) dim. matrices, covariant with respect to the adjoint action of \uq and in the limit q→1q\to 1, it reduces to the fuzzy sphere SF2(N)S_{F}^2(N). We construct the Dirac operator on the q-deformed fuzzy sphere-SqF2(N)S_{qF}^{2}(N) using the spinor modules of \uq. We explicitly obtain the zero modes and also calculate the spectrum for this Dirac operator. Using this Dirac operator, we construct the \uq invariant action for the spinor fields on SqF2(N)S_{qF}^{2}(N) which are regularised and have only finite modes. We analyse the spectrum for both qq being root of unity and real, showing interesting features like its novel degeneracy. We also study various limits of the parameter space (q, N) and recover the known spectrum in both fuzzy and commutative sphere.Comment: 19 pages, 6 figures, more references adde

    Unbounded representations of qq-deformation of Cuntz algebra

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    We study a deformation of the Cuntz-Toeplitz C∗C^*-algebra determined by the relations ai∗ai=1+qaiai∗,ai∗aj=0a_i^*a_i=1+q a_ia_i^*, a_i^*a_j=0. We define well-behaved unbounded *-representations of the *-algebra defined by relations above and classify all such irreducible representations up to unitary equivalence.Comment: 13 pages, Submitted to Lett. Math. Phy
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