Phase dependence of localization in the driven two-level model



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Creffield, Charles E. (2004) Phase dependence of localization in the driven two-level model. Europhysics letters, 66 (5). pp. 631-637. ISSN 0295-5075

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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 square-wave 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.

Item Type:Article
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© EDP Sciences.
The author gratefully acknowledges the hospitality of the University of Edinburgh, where this work was completed.

Uncontrolled Keywords:Physics; Quantum states
Subjects:Sciences > Physics > Materials
ID Code:37474
Deposited On:28 Apr 2016 17:02
Last Modified:28 Apr 2016 17:02

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