Regular-to-Chaotic Tunneling Rates: From the Quantum to the Semiclassical Regime (2009)
Löck, Steffen, Bäcker, Arnd, Ketzmerick, Roland, Schlagheck, Peter
We derive a prediction of dynamical tunneling rates from regular to chaotic phase-space regions combining the approach using a fictitious integrable system in the quantum regime with an improved...
Quality factors and dynamical tunneling in annular microcavities (2009)
Bäcker, Arnd, Ketzmerick, Roland, Löck, Steffen, Wiersig, Jan, Hentschel, Martina
The key characteristic of an optical mode in a microcavity is its quality factor describing the optical losses. The numerical computation of this quantity can be very demanding for present-day...
A switching mechanism in periodically driven quantum systems with dissipation (2009)
Ketzmerick, Roland, Wustmann, Waltraut
We introduce a switching mechanism in quantum systems induced by the combined effects of a periodic driving and a weak coupling to a heat bath. For an asymmetric double well potential the stationary...
Statistical mechanics of Floquet systems: the pervasive problem of near degeneracies (2008)
Hone, Daniel W., Ketzmerick, Roland, Kohn, Walter
The statistical mechanics of periodically driven ("Floquet") systems in contact with a heat bath exhibits some radical differences from the traditional statistical mechanics of undriven systems. In...
On universality of algebraic decays in Hamiltonian systems (2008)
Cristadoro, Giampaolo, Ketzmerick, Roland
Hamiltonian systems with a mixed phase space typically exhibit an algebraic decay of correlations and of Poincare' recurrences, with numerical experiments over finite times showing system-dependent...
Quantum Chaos and Spectral Transitions in the Kicked Harper Model (2007)
Karsten Kruse, Roland Ketzmerick, Theo Geisel
. In contrast to bounded systems, quantum chaos in extended systems may be associated with fractal spectra, metal-insulator transitions due to avoided band crossings, and spreading wave packets. In...
Universality in the flooding of regular islands by chaotic states (2007)
Bäcker, Arnd, Ketzmerick, Roland, Monastra, Alejandro G.
We investigate the structure of eigenstates in systems with a mixed phase space in terms of their projection onto individual regular tori. Depending on dynamical tunneling rates and the Heisenberg...
Directed Chaotic Transport in Hamiltonian Ratchets (2004)
Schanz, Holger, Dittrich, Thomas, Ketzmerick, Roland
We present a comprehensive account of directed transport in one-dimensional Hamiltonian systems with spatial and temporal periodicity. They can be considered as Hamiltonian ratchets in the sense that...
Naundorf, Björn, Ketzmerick, Roland
We study the energy spectrum and wave packet dynamics of electrons in a two-dimensional periodic potential subject to a perpendicular spatially modulated magnetic field. We observe avoided band...
Isolated resonances in conductance fluctuations in ballistic billiards (2002)
Bäcker, Arnd, Manze, Achim, Huckestein, Bodo, Ketzmerick, Roland
We study the isolated resonances occurring in conductance fluctuations of ballistic electron systems with a classically mixed phase space. In particular, we calculate the conductance and Wigner-Smith...
Isolated resonances in conductance fluctuations in ballistic billiards (2002)
Manze, Achim, Bäcker, Arnd, Huckestein, Bodo, Ketzmerick, Roland
We study numerically quantum transport through a billiard with a classically mixed phase space. In particular, we calculate the conductance and Wigner delay time by employing a recursive Green's...
Eigenstates Ignoring Regular and Chaotic Phase-Space Structures (2002)
Hufnagel, Lars, Ketzmerick, Roland, Otto, Marc-Felix, Schanz, Holger
We report the failure of the semiclassical eigenfunction hypothesis if regular classical transport coexists with chaotic dynamics. All eigenstates, instead of being restricted to either a regular...
Isolated resonances in conductance fluctuations and hierarchical states (2002)
Bäcker, Arnd, Manze, Achim, Huckestein, Bodo, Ketzmerick, Roland
We study the isolated resonances occurring in conductance fluctuations of quantum systems with a classically mixed phase space. We demonstrate that the isolated resonances and their scattering states...
Classical and Quantum Hamiltonian Ratchets (2001)
Dittrich, Thomas, Ketzmerick, Roland, Otto, Marc-Felix, Schanz, Holger
Classical and Quantum Hamiltonian Ratchets (2000)
Schanz, Holger, Otto, Marc-Felix, Ketzmerick, Roland, Dittrich, Thomas
We explain the mechanism leading to directed chaotic transport in Hamiltonian systems with spatial and temporal periodicity. We show that a mixed phase space comprising both regular and chaotic...
Quantum transport through ballistic cavities: soft vs. hard quantum chaos (1999)
Huckestein, Bodo, Ketzmerick, Roland, Lewenkopf, Caio H.
We study transport through a two-dimensional billiard attached to two infinite leads by numerically calculating the Landauer conductance and the Wigner time delay. In the generic case of a mixed...
Time Dependent Floquet Theory and Absence of an Adiabatic Limit (1997)
Hone, Daniel W., Ketzmerick, Roland, Kohn, Walter
Quantum systems subject to time periodic fields of finite amplitude, lambda, have conventionally been handled either by low order perturbation theory, for lambda not too large, or by exact...
Fractal Conductance Fluctuations in Generic Chaotic Cavities (1995)
It is shown that conductance fluctuations due to phase coherent ballistic transport through a chaotic cavity generically are fractals. The graph of conductance vs. externally changed parameter, e.g....