Microscopic and Macroscopic Samples of Atoms in Superposition States Studied by Attosecond Pulses
(2021) FYSM60 20211Mathematical Physics
Department of Physics
 Abstract
 In the present thesis, the interaction between atoms in superposition states and attosecond pulses is studied from the microscopic to the macroscopic regime. Using a semiclassical framework, three different models have been explored in order to investigate attosecond lightmatter interaction processes.
The first model is a microscopic, singleatom model. Through using this model, the absorption and the radiation of an external attosecond pulse was studied for several atomic superposition states and pulse energies. The second model was composed by two coupled atoms, where the interaction was described by either dipoledipole or radiation interaction. The model was validated by simulating the Förster resonant phenomena. In addition,... (More)  In the present thesis, the interaction between atoms in superposition states and attosecond pulses is studied from the microscopic to the macroscopic regime. Using a semiclassical framework, three different models have been explored in order to investigate attosecond lightmatter interaction processes.
The first model is a microscopic, singleatom model. Through using this model, the absorption and the radiation of an external attosecond pulse was studied for several atomic superposition states and pulse energies. The second model was composed by two coupled atoms, where the interaction was described by either dipoledipole or radiation interaction. The model was validated by simulating the Förster resonant phenomena. In addition, this model was used to determine the behaviour of the interactions with respect to separation distance and the initial states of the atoms. It was found that dipoledipole interaction is dominant in the near field, whilst radiation interaction is dominant in the far field. Additionally, it was found that superpositions with high principal quantum numbers increase the strength of the dipoledipole interaction but not the radiation interaction. The simulated results have been validated, in the shorttime regime, using perturbation theory.
The last model investigated in this thesis is a macroscopic manyatom model. It was implemented in order to simulate the propagation of an attosecond pulse through a large sample of atoms. Utilising this model, collective effects of manyatom systems were studied. It was found that a macroscopic sample emits collimated radiation and that dissipation of pulse energy in a macroscopic sample retains the behaviour of radiation produced by a single atom but that it is deformed by the propagation through the sample.
The models explored in this thesis can be used in the study of lightmatter interaction on the attosecond timescale with interatomic interactions and collective effects. The work presented here can be built on further to investigate research areas such as the dipoleblockade effect in cold atom physics, ionisation due to interatomic interaction or collective coherent effects. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/studentpapers/record/9060147
 author
 Stenquist, Axel ^{LU}
 supervisor

 Marcus Dahlström ^{LU}
 Felipe Zapata ^{LU}
 organization
 course
 FYSM60 20211
 year
 2021
 type
 H1  Master's Degree (One Year)
 subject
 keywords
 Mathematical physics, Theoretical physics, Atomic physics, Attosecond physics, Ultrafast physics, Numerical simulations, Microscopic, Mesoscopic, Macroscopic, Superposition, Light matter interaction, Quantum mechanics, Electromagnetism, Semiclassical, Attosecond transient absorption spectroscopy, ATAS, Förster resonance, FRET, Twoatom model, Interatomic interaction, Dipoledipole interaction, Manyatom model, Collective coherent effects, Timedependent configurationinteraction singles, TDCIS
 language
 English
 id
 9060147
 date added to LUP
 20210707 21:04:55
 date last changed
 20210707 21:04:55
@misc{9060147, abstract = {{In the present thesis, the interaction between atoms in superposition states and attosecond pulses is studied from the microscopic to the macroscopic regime. Using a semiclassical framework, three different models have been explored in order to investigate attosecond lightmatter interaction processes. The first model is a microscopic, singleatom model. Through using this model, the absorption and the radiation of an external attosecond pulse was studied for several atomic superposition states and pulse energies. The second model was composed by two coupled atoms, where the interaction was described by either dipoledipole or radiation interaction. The model was validated by simulating the Förster resonant phenomena. In addition, this model was used to determine the behaviour of the interactions with respect to separation distance and the initial states of the atoms. It was found that dipoledipole interaction is dominant in the near field, whilst radiation interaction is dominant in the far field. Additionally, it was found that superpositions with high principal quantum numbers increase the strength of the dipoledipole interaction but not the radiation interaction. The simulated results have been validated, in the shorttime regime, using perturbation theory. The last model investigated in this thesis is a macroscopic manyatom model. It was implemented in order to simulate the propagation of an attosecond pulse through a large sample of atoms. Utilising this model, collective effects of manyatom systems were studied. It was found that a macroscopic sample emits collimated radiation and that dissipation of pulse energy in a macroscopic sample retains the behaviour of radiation produced by a single atom but that it is deformed by the propagation through the sample. The models explored in this thesis can be used in the study of lightmatter interaction on the attosecond timescale with interatomic interactions and collective effects. The work presented here can be built on further to investigate research areas such as the dipoleblockade effect in cold atom physics, ionisation due to interatomic interaction or collective coherent effects.}}, author = {{Stenquist, Axel}}, language = {{eng}}, note = {{Student Paper}}, title = {{Microscopic and Macroscopic Samples of Atoms in Superposition States Studied by Attosecond Pulses}}, year = {{2021}}, }