527 research outputs found

    Alternating quaternary algebra structures on irreducible representations of sl(2,C)

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    We determine the multiplicity of the irreducible representation V(n) of the simple Lie algebra sl(2,C) as a direct summand of its fourth exterior power Λ4V(n)\Lambda^4 V(n). The multiplicity is 1 (resp. 2) if and only if n = 4, 6 (resp. n = 8, 10). For these n we determine the multilinear polynomial identities of degree ≤7\le 7 satisfied by the sl(2,C)-invariant alternating quaternary algebra structures obtained from the projections Λ4V(n)→V(n)\Lambda^4 V(n) \to V(n). We represent the polynomial identities as the nullspace of a large integer matrix and use computational linear algebra to find the canonical basis of the nullspace.Comment: 26 pages, 13 table

    The growth dynamics of the wedding-cake Interfaces

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    In the limit where the ratio of the surfaces diffusion coefficient to the deposition rate D/F ∞ → , the surface consists of wedding-cake structures. In order to understand the growth dynamics and the scaling properties of theses interfaces, we have calculated the time evolution of its width ω(L,t) for both one and two dimensional lattice. By the use of the dynamic scaling approach, we find that ω(L,t) scales with time t and length L as ω(L,t)≈Lα f(t/Lα/β ) where f is a scaling function and α and β are respectively the roughening and the growth exponents. The values of theses exponents are in good agreement with the theoritical ones predicted by the Edwards-Wilkinson equation.In the limit where the ratio of the surfaces diffusion coefficient to the deposition rate D/F ∞ → , the surface consists of wedding-cake structures. In order to understand the growth dynamics and the scaling properties of theses interfaces, we have calculated the time evolution of its width ω(L,t) for both one and two dimensional lattice. By the use of the dynamic scaling approach, we find that ω(L,t) scales with time t and length L as ω(L,t)≈Lα f(t/Lα/β ) where f is a scaling function and α and β are respectively the roughening and the growth exponents. The values of theses exponents are in good agreement with the theoritical ones predicted by the Edwards-Wilkinson equation

    Temporal fluctuations of current surface density in a triangular lattice

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    In this paper, we examine the effect of the temporal fluctuation current correlation in the surface diffusion process in a triangular lattice, in the framework of the lattice gas model. Our calculations are per found in small circular surfaces equivalent to the probe areas in the scanning microscopy experiments. We have found that the correlation function, in the non- interacting case, follows the law Öp . In the presence of repulsive interactions between mobile particles, it behaves like Öp exp(8γp). We have also calculated the collective diffusion coefficient by the linear response theory and by the characteristic time method, which reflect clearly the order-disorder effect on the diffusion.In this paper, we examine the effect of the temporal fluctuation current correlation in the surface diffusion process in a triangular lattice, in the framework of the lattice gas model. Our calculations are per found in small circular surfaces equivalent to the probe areas in the scanning microscopy experiments. We have found that the correlation function, in the non- interacting case, follows the law Öp . In the presence of repulsive interactions between mobile particles, it behaves like Öp exp(8γp). We have also calculated the collective diffusion coefficient by the linear response theory and by the characteristic time method, which reflect clearly the order-disorder effect on the diffusion

    Study of adatoms diffusion through current density fluctuation functions

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    In this work, we investigate the diffusion process by using a mean field lattice gas dynamical model. The temporal correlation function of the current density is calculated in a probe area of radius R. The latter is considered to test if the developed formulation can be applied to reproduce STM experiments. The obtained results concerning the effective diffusion coefficient exhibit clearly the order disorder transition effect translated by two minima appearing respectively at p=1/3 and p=2/3. The effect of the ordering phase at p=1/3 requires a threshold size more precisely, the minimum size system where, the ordering phase effect begins, to appear here is R=5.In this work, we investigate the diffusion process by using a mean field lattice gas dynamical model. The temporal correlation function of the current density is calculated in a probe area of radius R. The latter is considered to test if the developed formulation can be applied to reproduce STM experiments. The obtained results concerning the effective diffusion coefficient exhibit clearly the order disorder transition effect translated by two minima appearing respectively at p=1/3 and p=2/3. The effect of the ordering phase at p=1/3 requires a threshold size more precisely, the minimum size system where, the ordering phase effect begins, to appear here is R=5
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