9,700 research outputs found

    Nonlinear transforms of momenta and Planck scale limit

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    Starting with the generators of the Poincar\'e group for arbitrary mass (m) and spin (s) a nonunitary transformation is implemented to obtain momenta with an absolute Planck scale limit. In the rest frame (for m>0m>0) the transformed energy coincides with the standard one, both being mm. As the latter tends to infinity under Lorentz transformations the former tends to a finite upper limit mcoth(lm)=l1+O(l)m\coth(lm) = l^{-1}+ O(l) where ll is the Planck length and the mass-dependent nonleading terms vanish exactly for zero rest mass.The invariant m2m^{2} is conserved for the transformed momenta. The speed of light continues to be the absolute scale for velocities. We study various aspects of the kinematics in which two absolute scales have been introduced in this specific fashion. Precession of polarization and transformed position operators are among them. A deformation of the Poincar\'e algebra to the SO(4,1) deSitter one permits the implementation of our transformation in the latter case. A supersymmetric extension of the Poincar\'e algebra is also studied in this context.Comment: 10 pages, no figures, corrected some typo

    Canonical factorization and diagonalization of Baxterized braid matrices: Explicit constructions and applications

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    Braid matrices R^(θ)\hat{R}(\theta), corresponding to vector representations, are spectrally decomposed obtaining a ratio fi(θ)/fi(θ)f_{i}(\theta)/f_{i}(-\theta) for the coefficient of each projector PiP_{i} appearing in the decomposition. This directly yields a factorization (F(θ))1F(θ)(F(-\theta))^{-1}F(\theta) for the braid matrix, implying also the relation R^(θ)R^(θ)=I\hat{R}(-\theta)\hat{R}(\theta)=I.This is achieved for GLq(n),SOq(2n+1),SOq(2n),Spq(2n)GL_{q}(n),SO_{q}(2n+1),SO_{q}(2n),Sp_{q}(2n) for all nn and also for various other interesting cases including the 8-vertex matrix.We explain how the limits θ±\theta \to \pm \infty can be interpreted to provide factorizations of the standard (non-Baxterized) braid matrices. A systematic approach to diagonalization of projectors and hence of braid matrices is presented with explicit constructions for GLq(2),GLq(3),SOq(3),SOq(4),Spq(4)GL_{q}(2),GL_{q}(3),SO_{q}(3),SO_{q}(4),Sp_{q}(4) and various other cases such as the 8-vertex one. For a specific nested sequence of projectors diagonalization is obtained for all dimensions. In each factor F(θ)F(\theta) our diagonalization again factors out all dependence on the spectral parameter θ\theta as a diagonal matrix. The canonical property implemented in the diagonalizers is mutual orthogonality of the rows. Applications of our formalism to the construction of LL-operators and transfer matrices are indicated. In an Appendix our type of factorization is compared to another one proposed by other authors.Comment: 38 pages, no figure

    Computation of outflow rates from accretion disks around black holes

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    We self-consistently estimate the outflow rate from the accretion rates of an accretion disk around a black hole in which both the Keplerian and the sub-Keplerian matter flows simultaneously. While Keplerian matter supplies soft-photons, hot sub-Keplerian matter supplies thermal electrons. The temperature of the hot electrons is decided by the degree of inverse Comptonization of the soft photons. If we consider only thermally-driven flows from the centrifugal pressure-supported boundary layer around a black hole, we find that when the thermal electrons are cooled down, either because of the absence of the boundary layer (low compression ratio), or when the surface of the boundary layer is formed very far away, the outflow rate is negligible. For an intermediate size of this boundary layer the outflow rate is maximal. Since the temperature of the thermal electrons also decides the spectral state of a black hole, we predict that the outflow rate should be directly related to the spectral state.Comment: 9 pages, 5 figure
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