Tunneling of quantum rotobreathers

Article

关键词: INELASTIC-NEUTRON-SCATTERING;    SINE-GORDON BREATHER;    INTRINSIC LOCALIZED MODES;    DISCRETE BREATHERS;    NONLINEAR LATTICES;    PHASE-SPACE;    INSTABILITY INTERVALS;    PERTURBATION-THEORY;    ISOTOPIC MIXTURES;    EXISTENCE;   

DOI  :  10.1103/PhysRevB.65.214305

来源: SCIE

【 摘 要 】

We analyze the quantum properties of a system consisting of two nonlinearly coupled pendulums. This nonintegrable system exhibits two different symmetries: a permutational symmetry and another one related to the reversal of the total momentum of the system. Each of these symmetries is responsible for the existence of two kinds of quasidegenerate states. At sufficiently high energy, pairs of symmetry-related states glue together to form quadruplets. We show that, starting from the anticontinuous limit, particular quadruplets allow us to construct quantum states whose properties are very similar to those of classical rotobreathers. Contrary to the classical situation, the coupling between pendulums necessarily introduces a periodic exchange of energy between them at a frequency which is proportional to the energy splitting between quasidegenerate states related to the permutation symmetry. This splitting may remain very small as the coupling strength increases and is a decreasing function of the pair energy. The energy may be therefore stored in one pendulum during a time period very long as compared to the inverse of the internal rotobreather frequency.

【 授权许可】

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