Phase dependence of localization in the driven two-level model

Abstract

A two-level system subjected to a high-frequency driving field can exhibit an effect termed ``coherent destruction of tunneling'', in which the tunneling of the system is suppressed at certain values of the frequency and strength of the field. This suppression becomes less effective as the frequency of the driving field is reduced, and we show here how the detailed form of its fall-off depends on the phase of the driving, which for certain values can produce small local maxima (or revivals) in the overall decay. By considering a squarewave driving field, which has the advantage of being analytically tractable, we show how this surprising behavior can be interpreted geometrically in terms of orbits on the Bloch sphere. These results are of general applicability to more commonly used fields, such as sinusoidal driving, which display a similar phenomenology.

4 pages,4 eps figures. V2: minor changes, this version to be published in Europhysics Letters

References in corpus (2)

• Location of crossings in the Floquet spectrum of a driven two-level system
• Orbits of quantum states and geometry of Bloch vectors for $N$-level systems

Cited by in corpus (6)

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• Chaotic quantum ratchets and filters with cold atoms in optical lattices: properties of Floquet states
• Third order correction to localization in a two-level driven system
• High-order Harmonic Generation and Dynamic Localization in a driven two-level system, a non-perturbative solution using the Floquet-Green formalism
• Time-crystalline behavior in an engineered spin chain
• Effect of a high-frequency magnetic field on the resonant behavior displayed by a spin-$1/2$ particle under the influence of a rotating magnetic field