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Tesi etd-02082016-111906


Thesis type
Tesi di laurea magistrale
Author
ASTERIA, LUCA
URN
etd-02082016-111906
Title
De-excitation dynamics of cold Rydberg atoms
Struttura
FISICA
Corso di studi
FISICA
Commissione
relatore Morsch, Oliver
Parole chiave
  • atomic optics
  • cold rydberg atoms
Data inizio appello
29/02/2016;
Consultabilità
completa
Riassunto analitico
Rydberg atoms (the atoms in excited states with principal quantum number n&gt;20) have very large polarizability (which<br>scales as n^2) and therefore <br>interactions among them (van der Waals) are strong, on the order of about 10MHz for the typical mean interparticle distance of laser-cooled atomic gases (order of micrometer). <br><br><br>For this reason, and because of the great control their enhanced properties offer, <br>they have been proposed as simulators of many-body physics.<br><br>The excitation dynamics through laser light to the Rydberg state in a cold cloud (about 100microkelvin) of Rb atoms <br>has already shown evidences of strong<br>correlations which are a direct consequence of the interactions.<br><br>Here we present an experimental procedure which yields information on the interactions not through<br>the excitation dynamics, but rather through the dynamics of de-excitation:<br> we add, after the excitation process, a de-excitation phase through a coupling with a <br>rapidly-decaying level and measure the number of remaining excitations as <br>a function of time and of the frequency of the de-excitation laser.<br><br>A part of the thesis is dedicated to the experimental technique needed for the de-excitation process, <br>which requires a rapid change of the frequency of one of the excitation lasers. <br>We also briefly discuss other techniques involving time-varying frequencies (periodic modulation and sweep) <br>and their application to studies of Rydberg excitation dynamics. <br><br>The main chapter of this thesis is devoted to the results of the exploration of the de-excitation<br>scheme. We interpret our results in the light of numerical simulations which demonstrate that both the dynamics and the frequency dependence of the de-excitation yield information<br>about the spatial arrangement of the initial Rydberg excitations. We conclude by suggesting possible applications of our <br>procedure, such as the controlled preparation of spatial arrangements of Rydberg excitations by selectively removing a class of atoms at a certain interaction energy.
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