1,027 research outputs found
Complex paths for regular-to-chaotic tunneling rates
In generic Hamiltonian systems tori of regular motion are dynamically
separated from regions of chaotic motion in phase space. Quantum mechanically
these phase-space regions are coupled by dynamical tunneling. We introduce a
semiclassical approach based on complex paths for the prediction of dynamical
tunneling rates from regular tori to the chaotic region. This approach is
demonstrated for the standard map giving excellent agreement with numerically
determined tunneling rates.Comment: 5 pages, 4 figure
Weyl law for open systems with sharply divided mixed phase space
A generalization of the Weyl law to systems with a sharply divided mixed
phase space is proposed. The ansatz is composed of the usual Weyl term which
counts the number of states in regular islands and a term associated with
sticky regions in phase space. For a piecewise linear map, we numerically check
the validity of our hypothesis, and find good agreement not only for the case
with a sharply divided phase space, but also for the case where tiny island
chains surround the main regular island. For the latter case, a non-trivial
power law exponent appears in the survival probability of classical escaping
orbits, which may provide a clue to develop the Weyl law for more generic mixed
systems.Comment: 8 pages, 14 figure
Tunneling Mechanism due to Chaos in a Complex Phase Space
We have revealed that the barrier-tunneling process in non-integrable systems
is strongly linked to chaos in complex phase space by investigating a simple
scattering map model. The semiclassical wavefunction reproduces complicated
features of tunneling perfectly and it enables us to solve all the reasons why
those features appear in spite of absence of chaos on the real plane.
Multi-generation structure of manifolds, which is the manifestation of
complex-domain homoclinic entanglement created by complexified classical
dynamics, allows a symbolic coding and it is used as a guiding principle to
extract dominant complex trajectories from all the semiclassical candidates.Comment: 4 pages, RevTeX, 6 figures, to appear in Phys. Rev.
Semiclassical Study on Tunneling Processes via Complex-Domain Chaos
We investigate the semiclassical mechanism of tunneling process in
non-integrable systems. The significant role of complex-phase-space chaos in
the description of the tunneling process is elucidated by studying a simple
scattering map model. Behaviors of tunneling orbits are encoded into symbolic
sequences based on the structure of complex homoclinic tanglement. By means of
the symbolic coding, the phase space itineraries of tunneling orbits are
related with the amounts of imaginary parts of actions gained by the orbits, so
that the systematic search of significant tunneling orbits becomes possible.Comment: 26 pages, 28 figures, submitted to Physical Review
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