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Dissertation
Exchange-Bias-Dünnschichtsysteme - Charakterisierung, Modellierung und Anwendung
(2016-06-27)
In dieser Arbeit werden Exchange-Bias-Dünnschichtsysteme untersucht. Ein Fokus der Arbeit liegt auf der magnetooptischen Aktivität dieser Systeme und im speziellen wie sich diese optimieren lässt. Der zweite Fokus der Arbeit ist die Modellierung dieser Systeme. Aufbauend auf einem polykristallinen Ansatz wird eine neue rotierbare magnetische Anisotropie eingeführt, welche die Relaxationszeiten thermisch instabiler Körner im AF berücksichtigt.
Aufsatz
Detecting ultrafast interatomic electronic processes in media by fluorescence
(In: New journal of physics. - London : IOP, 2014, 16, 102002, 1-9, 2014)
Interatomic coulombic decay (ICD), a radiationless transition in weakly bonded systems, such as solutes or van der Waals bound aggregates, is an effective source for electrons of low kinetic energy. So far, the ICD processes could only be probed in ultra-high vacuum by using electron and/or ion spectroscopy. Here we show that resonant ICD processes can also be detected by measuring the subsequently emitted characteristic fluorescence radiation, which makes their study in dense media possible.
Dissertation
Bestimmung der magnetischen Streufeldstärke von künstlichen magnetischen Domänen austauschverschobener Dünnschichtsysteme und deren Einfluss auf die Selbstassemblierung organischer Moleküle
(2015-11-16)
Die lokale Anlagerung molekularer Substanzen auf Oberflächen ist technologisch von großem Interesse. Die Beeinflussung selbstassemblierender Materialien bietet dabei große Vorteile, da sie kostengünstig und großflächig angewendet werden kann. Untersuchungen einer solchen Beeinflussung mithilfe von magnetischen Feldern wurden bisher jedoch noch nicht durchgeführt. Ursache hierfür ist das, insbesondere bei der Verwendung von diamagnetischen Substanzen, geringe induzierte magnetische Moment und die daraus resultierenden ...
Dissertation
Optimizing Robust Quantum Gates in Open Quantum Systems
(2015-05-27)
We are currently at the cusp of a revolution in quantum technology that relies not just on the passive use of quantum effects, but on their active control. At the forefront of this revolution is the implementation of a quantum computer. Encoding information in quantum states as “qubits” allows to use entanglement and quantum superposition to perform calculations that are infeasible on classical computers. The fundamental challenge in the realization of quantum computers is to avoid decoherence – the loss of quantum ...
Aufsatz
Asymptotic model for shape resonance control of diatomics by intense non-resonant light: universality in the single-channel approximation
(2015)
Non-resonant light interacting with diatomics via the polarizability anisotropy couples different
rotational states and may lead to strong hybridization of the motion. The modification of shape
resonances and low-energy scattering states due to this interaction can be fully captured by an
asymptotic model, based on the long-range properties of the scattering (Crubellier et al 2015 New J.
Phys. 17 045020). Remarkably, the properties of the field-dressed shape resonances in this asymptotic
multi-channel description ...
Aufsatz
Asymptotic model for shape resonance control of diatomics by intense non-resonant light
(2015)
We derive a universal model for atom pairs interacting with non-resonant light via the polarizability
anisotropy, based on the long range properties of the scattering. The corresponding dynamics can be
obtained using a nodal line technique to solve the asymptotic Schrödinger equation. It consists of
imposing physical boundary conditions at long range and vanishing the wavefunction at a position
separating the inner zone and the asymptotic region. We show that nodal lines which depend on the
intensity of the ...
Aufsatz
Femtosecond wavepacket interferometry using the rotational dynamics of a trapped cold molecular ion
(2015)
A Ramsey-type interferometer is suggested, employing a cold trapped ion and two time-delayed offresonant
femtosecond laser pulses. The laser light couples to the molecular polarization anisotropy,
inducing rotational wavepacket dynamics. An interferogram is obtained from the delay dependent
populations of the final field-free rotational states. Current experimental capabilities for cooling and
preparation of the initial state are found to yield an interferogram visibility of more than 80%. The
interferograms can ...