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|Type:||Artigo de periódico|
|Title:||Periodic Librations And Their Effect On The Quantum Energy Spectrum|
|Author:||De Almeida A.M.O.|
De Aguiar M.A.M.
|Abstract:||Classical Hamiltonian systems with time-reversal symmetry have periodic orbits of two kinds-symmetry pairs (rotations) and self-symmetric orbits (librations). For integrable anharmonic oscillators with two freedoms, almost all of periodic orbits of any period are rotation pairs. However, we show that a KAM-type perturbation alters this balance, such that a finite fraction of the low-period orbits are librations. The generic bifurcations undergone by librations are isomorphic to those of non-symmetric orbits of structurally stable Hamiltonians, with the addition of an extra type of periodic bifurcation. We determine the unfolding of this bifurcation as time-reversal symmetry is broken. The effect of this non-structurally stable bifurcation on the quantum mechanical density of states is also obtained. The present results also hold for systems that are symmetric with respect to general anti-unitary symmetries in quantum mechanics, corresponding to anticanonically reversible Hamiltonian classical systems. © 1990.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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