Polarization Independence of Microwave “Ionization” Thresholds of Excited Hydrogen Atoms near the Principal Resonance

Bellermann, M. R. W.; Koch, Peter; Mariani, David; Richards, D

doi:10.1103/physrevlett.76.892

Cited by 38 publications

(34 citation statements)

References 29 publications

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“…In most experiments on microwave driven Rydberg atoms, linearly polarized (LP) microwaves have been used [132,133,[135][136][137]. For circular polarization (CP), first experiments were performed for alkali atoms in the late eighties [138,139], with hydrogen atoms following only recently [134]. The latter experiments also studied the general case of elliptic polarization (EP).…”

Section: Rydberg States In Circularly Polarized Microwave Fieldsmentioning

confidence: 99%

Non-dispersive wave packets in periodically driven quantum systems

2002

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With the exception of the harmonic oscillator, quantum wave packets usually spread as time evolves. This is due to the non-linear character of the classical equations of motion which makes the various components of the wave packet evolve at various frequencies. We show here that, using the non-linear resonance between an internal frequency of a system and an external periodic driving, it is possible to overcome this spreading and build non-dispersive (or non-spreading) wave packets which are well localized and follow a classical periodic orbit without spreading. From the quantum mechanical point of view, the non-dispersive wave packets are time periodic eigenstates of the Floquet Hamiltonian, localized in the non-linear resonance island. We discuss the general mechanism which produces the non-dispersive wave packets, with emphasis on simple realization in the electronic motion of a Rydberg electron driven by a microwave field. We show the robustness of such wave packets for a model one-dimensional as well as for realistic three-dimensional atoms. We consider their essential properties such as the stability versus ionization, the characteristic energy spectrum and long lifetimes. The requirements for experiments aimed at observing such non-dispersive wave packets are also considered. The analysis is extended to situations in which the driving frequency is a multiple of the internal atomic frequency. Such a case allows us to discuss non-dispersive states composed of several, macroscopically separated wave packets communicating among themselves by tunneling. Similarly we briefly discuss other closely related phenomena in atomic and molecular physics as well as possible further extensions of the theory. (C) 2002 Elsevier Science B.V. All rights reserved

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Section: Rydberg States In Circularly Polarized Microwave Fieldsmentioning

confidence: 99%

Non-dispersive wave packets in periodically driven quantum systems

2002

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“…Figure 4 compares the scaled 10%-and 90%0-thresholds F0(0.1) and F0(0.9), respectively, for the 9.923 GHz LP data set from [1] with those from the present 9.904 GHz LP data set [81,82] obtained with the cavity described in Sec. 2.2.…”

Section: Classical Phase-space Portraitsmentioning

confidence: 99%

“…Because the details of the experimental method are given in [1,2,[80][81][82][83], this discussion is brief. Ions extracted from a hydrogen ion source were accelerated, focused, and deflected in a mass-analyzer magnet tuned to transmit protons.…”

Section: Apparatusmentioning

confidence: 99%

“…(No similar, simple statement applies to smaller values of Pion and/or 75 < n0 ≤ 98.) Because, for these parameters, small departures from CP to EP lowered the large-Ρion threshold, we used this dependence, usually for n0 = 58, to fine-tune the polarization to CP [36,82,83] giving α = 1.00 ± 0.05 and δ = 90° ± 1°.…”

Section: Ionization Curvesmentioning

confidence: 99%

“…2 were used to measure [81,82] 9.904 GHZ ioniZation curves for LP, CP, and a number of different values of EP. From these curves were obtained the 10% and 50% ionization thresholds plotted in Fig.…”

Section: Polarization Dependence Near the Main Resonance Zonementioning

confidence: 99%

See 2 more Smart Citations

Polarization Dependence of Microwave "ionization" of Excited Hydrogen Atoms

Koch

1998

Acta Phys. Pol. A

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After a brief review of the ionization of excited hydrogen atoms by a linearly polarized field, we discuss experimental results for the polarization dependence of this process. Experiments at ω/2π = 9.904 GHz used two different ranges of principal quantum number n 0 between 29 and 98. At low scaled frequencies, Ω 0 0.1, ionization data for certain narrow ranges of n0 exhibit striking sensitivity to fields with elliptical polarization not too far from circular polarization. Classical calculations reproduce this behavior and show it to be the result of 2ω driving terms that appear when the Hamiltonian is transformed to a frame rotating at ω. It shows how higher-dimensional dynamics can influence the ionization and be used to control it when the polarization departs from linear or circular polarization. At higher scaled frequencies, 0.6 < Ω0 1.4, near the onset of ionization circularly and elliptically polarized data show surprising similarities with linearly polarized data in a parameter regime where the ionization dynamics is dominated by the influence of the pendulumlike resonance zone centered at scaled frequency noω 1. The stabilizing influence of this zone can be understood classically, but nonclassical stability associated with quantal separatrix states at its edge is a semiclassical effect.

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Breaking Time Reversal Symmetry in Chaotic Driven Rydberg Atoms

2000

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We consider the dynamics of Rydberg states of the hydrogen atom driven by a microwave field of elliptical polarization, with a possible additional static electric field. We concentrate on the effect of a resonant weak field whose frequency is close to the Kepler frequency of the electron around the nucleus which essentially produces no ionization of the atom, but completely mixes the various states inside an hydrogenic manifold of fixed principal quantum number. For sufficiently small fields, a perturbative approach (both in classical and quantum mechanics) is relevant. For some configurations of the fields, the classical secular motion (i.e., evolution in time of the elliptical electronic trajectory) is shown to be predominantly chaotic. Changing the orientation of the static field with respect to the polarization of the microwave field allows us to investigate the effect of generalized time-reversal symmetry breaking on the statistical properties of energy levels. Academic Press

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Polarization Independence of Microwave “Ionization” Thresholds of Excited Hydrogen Atoms near the Principal Resonance

Cited by 38 publications

References 29 publications

Non-dispersive wave packets in periodically driven quantum systems

Non-dispersive wave packets in periodically driven quantum systems

Polarization Dependence of Microwave "ionization" of Excited Hydrogen Atoms

Breaking Time Reversal Symmetry in Chaotic Driven Rydberg Atoms

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