Driven Tunnelling with Dissipation

Dittrich, Thomas; Oelschlägel, B.; Hänggi, Peter

doi:10.1209/0295-5075/22/1/002

Cited by 94 publications

(74 citation statements)

References 49 publications

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“…It is known [16] that the coherent destruction of tunneling survives to some extent in presence of a coupling to the environment. Certainly, the system will relax in presence of an environment; however, as it is demonstrated in [16], the relaxation process can considerably be slowed down in the presence of a CDT-field.…”

Section: B Freezing the Coherent Dynamics Of A Driven Two-level Systemmentioning

confidence: 99%

“…To achieve this goal, various approaches have been undertaken in recent years. (i) It has been shown that the effect of coherent destruction of tunneling (see above) can be used to slow down the relaxation of a quantum system to its asymptotic equilibrium [16]. (ii) Moreover, a suitable tailored sequence of radio-frequency pulses ("quantum bang-bang" [17] or "parity kicks" [18]) that repeatedly flip the state of a two-level atom may be used to suppress decoherence.…”

Section: Introductionmentioning

confidence: 99%

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Controlling decoherence of a two-level atom in a lossy cavity

Thorwart

Hartmann

Goychuk

et al. 2000

Journal of Modern Optics

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By use of external periodic driving sources, we demonstrate the possibility of controlling the coherent as well as the decoherent dynamics of a two-level atom placed in a lossy cavity. The control of the coherent dynamics is elucidated for the phenomenon of coherent destruction of tunneling (CDT), i.e., the coherent dynamics of a driven two-level atom in a quantum superposition state can be brought practically to a complete standstill. We study this phenomenon for different initial preparations of the two-level atom. We then proceed to investigate the decoherence originating from the interaction of the two-level atom with a lossy cavity mode. The loss mechanism is described in terms of a microscopic model that couples the cavity mode to a bath of harmonic field modes. A suitably tuned external cw-laser field applied to the two-level atom slows down considerably the decoherence of the atom. We demonstrate the suppression of decoherence for two opposite initial preparations of the atomic state: a quantum superposition state as well as the ground state. These findings can be used to the effect of a proficient battling of decoherence in qubit manipulation processes.

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Section: B Freezing the Coherent Dynamics Of A Driven Two-level Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Controlling decoherence of a two-level atom in a lossy cavity

Thorwart

Hartmann

Goychuk

et al. 2000

Journal of Modern Optics

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“…In the second case it cannot be treated as a system with proper eigenstates and eigenenergies. A Markovian approach based on a quasienergy spectrum has been implemented in recent work on driven Rydberg atoms [6] and driven dissipative tunneling [7].…”

Section: Introductionmentioning

confidence: 99%

Floquet-Markovian description of the parametrically driven, dissipative harmonic quantum oscillator

1997

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Using the parametrically driven harmonic oscillator as a working example, we study two different Markovian approaches to the quantum dynamics of a periodically driven system with dissipation. In the simpler approach, the driving enters the master equation for the reduced density operator only in the Hamiltonian term. An improved master equation is achieved by treating the entire driven system within the Floquet formalism and coupling it to the reservoir as a whole. The different ensuing evolution equations are compared in various representations, particularly as Fokker-Planck equations for the Wigner function. On all levels of approximation, these evolution equations retain the periodicity of the driving, so that their solutions have Floquet form and represent eigenfunctions of a non-unitary propagator over a single period of the driving. We discuss asymptotic states in the long-time limit as well as the conservative and the high-temperature limits. Numerical results obtained within the different Markov approximations are compared with the exact path-integral solution. The application of the improved Floquet-Markov scheme becomes increasingly important when considering stronger driving and lower temperatures. 42.50.Lc, 03.65.Sq Typeset using REVT E X † Present address:

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“…Equations (22), (24), consequently allow to express the interaction picture operatorc † 1 (t−τ, t) appearing in the current formula (13) via c α (t), dressed by exponential prefactors. This spectral decomposition allows one to carry out the time and energy integrals in the expression (13) for the net current entering the wire from the left lead.…”

Section: B Floquet Decompositionmentioning

confidence: 99%

“…In the subspace of a single electron, R αβ reduces to the density matrix in the basis of the Floquet states which has been used to describe dissipative driven quantum systems in Refs. 16,18,23,24,25,26. The next step towards the stationary current is to find the Fourier coefficients R αβ,k at asymptotic times.…”

Section: B Floquet Decompositionmentioning

confidence: 99%

Resonant laser excitation of molecular wires

Kohler

Lehmann

Camalet

et al. 2002

Israel Journal of Chemistry

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We investigate the influence of external laser excitations on the average current through bridged molecules. For the computation of the current, we use a numerically very efficient formalism that is based on the Floquet solutions of the time-dependent molecule Hamiltonian. It is found that the current as a function of the laser frequency exhibits characteristic peaks originating from resonant excitations of electrons to bridge levels which are unoccupied in the absence of the radiation. The electrical current through the molecule can exhibit a drastic enhancement by several orders of magnitude.

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Driven Tunnelling with Dissipation

Cited by 94 publications

References 49 publications

Controlling decoherence of a two-level atom in a lossy cavity

Controlling decoherence of a two-level atom in a lossy cavity

Floquet-Markovian description of the parametrically driven, dissipative harmonic quantum oscillator

Resonant laser excitation of molecular wires

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