707 research outputs found

    Totally real Thue inequalities over imaginary quadratic fields

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    Let F(x,y)F(x,y) be an irreducible binary form of degree 3\geq 3 with integer coefficients and with real roots. Let MM be an imaginary quadratic field, with ring of integers ZMZ_M. Let K>0K>0. We describe an efficient method how to reduce the resolution of the relative Thue inequalities F(x,y)K    (x,yZM) |F(x,y)|\leq K \;\; (x,y\in Z_M) to the resolution of absolute Thue inequalities of type F(x,y)k    (x,yZ). |F(x,y)|\leq k \;\; (x,y\in Z). We illustrate our method with an explicit example

    Exciton Optical Absorption in Self-Similar Aperiodic Lattices

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    Exciton optical absorption in self-similar aperiodic one-dimensional systems is considered, focusing our attention on Thue-Morse and Fibonacci lattices as canonical examples. The absorption line shape is evaluated by solving the microscopic equations of motion of the Frenkel-exciton problem on the lattice, in which on-site energies take on two values, according to the Thue-Morse or Fibonacci sequences. Results are compared to those obtained in random lattices with the same stechiometry and size. We find that aperiodic order causes the occurrence of well-defined characteristic features in the absorption spectra which clearly differ from the case of random systems, indicating a most peculiar exciton dynamics. We successfully explain the obtained spectra in terms of the two-center problem. This allows us to establish the origin of all the absorption lines by considering the self-similar aperiodic lattices as composed of two-center blocks, within the same spirit of the renormalization group ideas.Comment: 16 pages in REVTeX 3.0. 2 figures on request to F. D-A ([email protected]
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