Doctoral theses
Current Record: 1985 of 2443
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| Identifier |
000381467 |
| Title |
Quantum measurements of spin in alkali atoms and bio-molecules |
| Alternative Title |
Κβαντικές μετρήσεις του σπιν σε αλκαλικά άτομα και βιομόρια |
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Author
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Δελλής, Αργύρης
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Thesis advisor
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Κομίνης, Ιωάννης
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| Abstract |
This dissertation describes the results of the research work done by author at the Laboratory
of Quantum Science and Technology.
In Part I we report on the experimental observation and theoretical justification of
a novel effect, the transfer of spin noise from one atomic species to another, through
the mechanism of spin exchange. Essentially, we extend the foundational studies of
spin exchange into the deeper layer of quantum fluctuations. The signature of spin
noise exchange is an increase of the total spin noise power at low magnetic fields
where the two-species spin noise resonances overlap. We will demonstrate experimentally
and prove theoretically that the total spin noise power of a two-species
spin ensemble like 85 Rb - 87 Rb, exhibits a counter-intuitive dependence on the applied
magnetic field. This is the experimental signature of spin noise exchange. This new effect is
observable when the two atomic species have overlapping spin resonances.
The Part II is about the dynamics of Radical Pair reactions. Radical Pair reactions
were recently shown to represent a rich biophysical laboratory for the application
of quantum measurement theory methods and concepts. We here propose a concrete
experimental test that can clearly discriminate among the fundamental master
equations currently attempting to describe the quantum dynamics of these reactions.
The proposed measurement based on photon statistics of fluorescing radical
pairs is shown to be molecular-model-independent and capable of elucidating the
singlet–triplet decoherence inherent in the radical–ion-pair recombination process.
Moreover, recent experiments have provided growing evidence for the Radical Pair
magneto-reception mechanism, while recent theoretical advances have unraveled the
quantum nature of Radical Pair reactions, which were shown to manifest a host
of quantum-information-science concepts and effects, like quantum measurement,
quantum jumps and the quantum Zeno effect. We here show that the quantum Zeno
effect provides for the robustness of the avian compass mechanism, and immunizes
its magnetic and angular sensitivity against the deleterious and molecule-specific
exchange and dipolar interactions.
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| Language |
English |
| Subject |
Chemical compass |
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Magnetic resonance |
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Photon statistics |
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Radical pair |
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Zero effect |
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Ζεύγη ριζών |
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Μαγνητικός συντονισμός |
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Στατιστική φωτονίων |
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Φαινόμενα ζήνωμα |
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Χημική πυξίδα |
| Issue date |
2013-10-14 |
| Collection
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School/Department--School of Sciences and Engineering--Department of Physics--Doctoral theses
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Type of Work--Doctoral theses
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| Permanent Link |
https://elocus.lib.uoc.gr//dlib/a/e/6/metadata-dlib-1387270450-995421-14060.tkl
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| Views |
652 |
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