Quantum Transport

1. Quantum Transport in Internal Degrees of Freedom

Would you have guessed that the dynamics of the electron in the hydrogen atom can be chaotic? It can indeed be very complex when the atom is exposed to a time-periodic driving force, especially in the regime of highly excited Rydberg orbits where the sensitivity of states is large. The electronic motion is best described in energy space, in which the electron can gain energy by the drive and eventually it may ionise. Classically, the electronic dynamics is typically chaotic, meaning that a slight change in the initial conditions may lead to a completely different classical trajectory. Quantum mechanically, the electronic dynamics can be stabilised by dynamical localisation. Moreover, Rydberg atoms are good playground to study fundamental aspects of transport in mixed regular-chaotic phase space. Chaos-assisted tunnelling and the stability of quantum wave packets anchored to classically stable regions in phase space are just a few aspects we are looking at.

2. Quantum Transport in External Degrees of Freedom

Ultracold atoms loaded into optical lattices open a new arena for the experimental investigation of quantum transport phenomena in spatially periodic potentials. Possibly amended by particle-particle interactions and decoherence, external perturbations (such as static and/or time-dependent fields) modify the dynamics of ultracold quantum matter. We try to understand the underlying phenomena in detail, and to use our understanding for the controlling and engineering of complex quantum dynamics in ultracold matter. Our research in this field is inspired and partially guided by ongoing experiments at Auckland (New Zealand), Kaiserslautern (Germany), Pisa (Italy), Stillwater (USA), Tokyo (Japan).

Scaling function 1 Scaling function 2



Phase space portrait (inset) and energy increase as a function of the scaled interaction time of kicked cold atoms in the semiclassical limit (left), and rescaled energy as a function of the single scaling parameter in the semiclassical limit (blue) and near to ballistic quantum resonant motion (red).



3. Mixing Internal and External Degrees of Freedom

Combining the above two aspects of quantum transport is highly interesting for various proposals of quantum computers and for the engineering of entanglement between extern and internal degrees of freedom. Different atomic energy levels, for instance, usually couple differently to external fields, allowing for a direct measurement of the overlap of differently evolved states, an observable named "fidelity".


Publications

  • G. Summy and S. Wimberger
    Quantum random walk of a Bose-Einstein condensate in momentum space, Phys. Rev. A 93, 023638 (2016)
  • R. Labouvie, B. Santra, S. Heun, S. Wimberger, and H. Ott
    Negative differential conductivity in an interacting quantum gas, Phys. Rev. Lett. 115, 050601 (2015)
  • A. Ivanov, G. Kordas, A. Komnik, and S. Wimberger
    Bosonic transport through a chain of quantum dots, Eur. Phys. J. B 86, 345 (2013)
  • B. Herwerth, M. DeKieviet, J. Madronero, and S. Wimberger
    Quantum reflection from an oscillating surface, J. Phys. B 46, 141002(FTC) (2013)
  • T. Schell, M. Sadgrove, K. Nakagawa, and S. Wimberger
    Engineering transport by concatenated maps, Fluctuation and Noise Letters 12, 1340004 (2013)
  • S. Micciche, A. Buchleitner, F. Lillo, R. Mantegna, T. Paul, and S. Wimberger
    Scale-free relaxation of a wave packet in a quantum well with power-law tails, NJP 15, 033033 (2013)
  • A. Kolovsky, J. Link, and S. Wimberger
    Energetically constrained co-tunneling of cold atoms, New J. Phys. 14, 075002 (2012)
  • M. Sadgrove, S. Wimberger, and K. Nakagawa
    Phase-selected momentum transport in ultra-cold atoms, Eur. Phys. J. D 66, 155 (2012)
  • G. Tayebirad, R. Mannella, and S. Wimberger
    Engineering interband transport by time-dependent disorder, Phys. Rev. A 84, 031605(R) (2011)
  • P. Plötz, J. Madronero, and S. Wimberger
    Collapse and revival in inter-band oscillations of a two-band Bose-Hubbard model, J. Phys. B 43, 081001(FTC) (2010)
  • M. Abb, I. Guarneri, and S. Wimberger
    Pseudoclassical theory for fidelity of nearly resonant quantum rotors, Phys. Rev. E 80, 035206(R) (2009)
  • M. Sadgrove and S. Wimberger
    Pseudo-classical theory for directed transport at quantum resonance, New J. Phys. 11, 083027 (2009)
  • A. Zenesini, H. Lignier, G. Tayebirad, J. Radogostowicz, D. Ciampini, R. Mannella, S. Wimberger, O. Morsch, and E. Arimondo
    Time-resolved measurement of Landau-Zener tunneling in periodic potentials, Phys. Rev. Lett. 103, 090403 (2009)
  • D. Witthaut, F. Trimborn, and S. Wimberger
    Dissipation-induced coherence and stochastic resonance of an open two-mode Bose-Einstein condensate, Phys. Rev. A 79, 033621 (2009)
  • D. Witthaut, F. Trimborn, and S. Wimberger
    Dissipation induced coherence of a two-mode Bose-Einstein condensate, Phys. Rev. Lett. 101, 200402 (2008)
  • M. Sadgrove, S. Wimberger, S. Parkins, and R. Leonhardt
    Scaling law and stability for a noisy quantum system, Phys. Rev. E 78, 025206(R) (2008)
  • F. Trimborn, D. Witthaut, and S. Wimberger
    Mean-field dynamics of a two-mode Bose-Einstein condensate subject to noise and dissipation, J. Phys. B 41, 171001(FTC) (2008)
  • A. Zenesini, C. Sias, H. Lignier, Y. Singh, D. Ciampini, O. Morsch, R. Mannella, E. Arimondo, A. Tomadin, and S. Wimberger
    Resonant tunneling of Bose-Einstein condensates in optical lattices, New J. Phys. 10, 053038 (2008)
  • P. Buonsante and S. Wimberger
    Engineering many-body quantum dynamics by disorder, Phys. Rev. A 77, 041606(R) (2008)
  • A. Tomadin, R. Mannella, and S. Wimberger
    Many-body Landau-Zener tunneling in the Bose-Hubbard model, Phys. Rev. A 77, 013606 (2008)
  • A. Tomadin, R. Mannella, and S. Wimberger
    Many-body interband tunneling as a witness for complex dynamics in the Bose-Hubbard model, Phys. Rev. Lett. 98, 130402 (2007)
  • C. Sias, A. Zenesini, H. Lignier, S. Wimberger, D. Ciampini, O. Morsch, and E. Arimondo
    Resonantly enhanced tunneling of Bose-Einstein condensates in periodic potentials, Phys. Rev. Lett. 98, 120403 (2007)
  • S. Wimberger, D. Ciampini, O. Morsch, R. Mannella, and E. Arimondo
    Engineered quantum transport in extended periodic potentials, J. Phys. Conf. Ser. 67, 012060 (2007)
  • R. Khomeriki, S. Ruffo, and S. Wimberger
    Driven Collective Quantum Tunneling of Ultracold Atoms in Engineered Optical Lattices , Europhys. Lett. 77, 40005 (2007)
  • A. Facchini, S. Wimberger, and A. Tomadin
    Multifractal fluctuations in the survival probability of an open quantum system, Physica A 376, 266-274 (2007)
  • E. Persson, S. Fuhrthauer, S. Wimberger, and J. Burgdörfer
    Transient localization in the kicked Rydberg atom , Phys. Rev. A 74, 053417 (2006)
  • G. Carlo, G. Benenti, G. Casati, S. Wimberger, O. Morsch, R. Mannella, and E. Arimondo
    Chaotic ratchet dynamics with cold atoms in a pair of pulsed optical lattices, Phys. Rev. A 74, 033617 (2006)
  • S. Wimberger, P. Schlagheck, Ch. Eltschka, and A. Buchleitner
    Resonance-Assisted Decay of Nondispersive Wave Packets, Phys. Rev. Lett. 97, 043001 (2006)
  • J. Madronero, A. Ponomarev, A.R.R. Carvalho, S. Wimberger, C. Viviescas, A.R. Kolovsky, K. Hornberger, P. Schlagheck, A. Krug, and A. Buchleitner
    Quantum chaos, transport, and control - in quantum optics, in: M. Scully and G. Rempe (Eds.), Adv. At. Mol. Opt. Phys. 53, 33, Elsevier, Amsterdam 2006

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