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Seminar: Dynamics in Strong Fields – Details

The literature in the summaries can be downloaded from within the LMU network from the repspective journal web sites. It should provide you with a first impression of the topic. A more detailed guide to literature will be provided after you have selected a topic.

Strong-field control of a Fano resonance

A beautiful recent experiment has demonstrated that decay of doubly excited states of Helium -- which generate the typical Fano profile in photo-emission spectra -- can be modified by a time-delayed infra-red pulse. A theoretical model for the process was presented. In the seminar, a short summary of Fano-theory should be presented, a run-down of the experimental facts, and the theoretical model should be discussed.

Ott et al., Science 340, 716 (2013): Lorentz Meets Fano in Spectral Line Shapes: A Universal Phase and Its Laser Control (Link)

Fano, Phys. Rev. 124, 1866–1878 (1961): Effects of Configuration Interaction on Intensities and Phase Shifts (Link)

Strong-field induced states

Based on an analysis of light-matter interactions in the so-called Kramers-Henneberger frame of reference, the existence of quasi-bound states of atoms was predicted. These states owe their existence exclusively to the light field. Similarly, one may produce "molecules without electrons'', i. e., bind two protons in a strong light field. The seminar will elaborate on Kramers-Henneberger systems, and discuss numerical and experimental evidence for the actual exisitence of such states.

Pont et al., Phys. Rev. Lett. 61, 939–942 (1988), Dichotomy of the Hydrogen Atom in Superintense, High-Frequency Laser Fields, (Link)

Smirnova et al., Phys. Rev. Lett. 90, 243001 (2003): Molecule without Electrons: Binding Bare Nuclei with Strong Laser Fields (Link)

Filamentation

Strong pulses propagating through gas tend to break up into "filaments'', i. e., several thin plasma channels that guide the light. The mechanism plays a key role for intense pulse propagation. The seminar will report the theoretical models for filamentation.

N Akozbek et al., Phys. Rev. E 61, 4540–4549 (2000), Femtosecond pulse propagation in air: Variational analysis (Link)

Time-resolution of tunneling

The tunneling process has baffled physicists ever since they found out it existed. In very recent times, time-resolution of the tunneling process has come into experimental reach. While beautiful experiments have been done, their interpretation in terms of tunneling dynamics remains tricky. The seminar will report concepts of tunneling dynamics in view of the recent experiments.

Shafir et al., “Resolving the time when an electron exits a tunneling barrier, Nature 485, 343 (2012). (Link)

Pfeiffer et al., “Attoclock reveals natural coordinates of the laser-induced tunnelling current flow in atoms” Nature Physics, vol. 8, pp. 76-80, (2012),

Nano-atto physics

A new experimental development unites attosecond time-scales with the nano-meter size of metal tips. Macrocscopic, plasmonic, and electronic time and length scales become intertwined. In the seminar, qualitative mechanisms and theory models as well as numerical approaches will be discussed.

Krüger et al., Nature 475, 78–81 (2011): Attosecond control of electrons emitted from a nanoscale metal tip (Link))

Strong-field control of molecules

One dream of short pulse physics has been to control the motion of atoms in molecules, i. e., control chemical reactions or molecular breakup. Recent years have seen first realizations of this idea on the few-femtosecond time scale. In the seminar the theory of electronic exciations and diatomic break-up will be reported.

Lepine, Chemical Physics Letters 578, 1 (2013): Molecular applications of attosecond laser pulses (Link)

Photo-emission from molecules (Vinay Majety)

Vinay Majety will present first results of his thesis work on strong field ionization of realistic molecules. Physical, quantum chemical, and computational aspects will be discussed.

The birth of a plasmon (Mattia Lupetti)

Mattia Luppetti will describe how attosecond pulses may be used to directly to observe the emergence of a plasmon.

The strong field 2-electron problem (Alejandro Zielinski)

The accurate solution of the time-dependent Schrödinger equation is a challenging task, even when advantage can be taken of its rotational symmetry. It essentially has resisted solution, when a strong field is present. Alejandro will show how it can be done using new mathematical techniques and smart computing.

Few-electron dynamics at surfaces (Jakob Liss)

Transferring methods from strong-field molecular physics, Jakob will present our first attempts to quantum-mechanically describe the few-electron dynamcis presumably induced, when a strong laser pulse hits a solid surface.