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Title
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Fluctuations in multicomponent quantum fluids
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Author
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Abstract
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| In this thesis the behaviour of quantum fluids out of equilibrium is studied. These are ultracold gases in which quantum mechanical effects - usually only visible at the atomic scale - determine the macroscopic properties. The work is composed of several related projects, in which the central role of quantum fluctuations is highlighted. In the Gaussian theory for quantum systems, fluctuations are approximated as corrections to a classical description of the fluid. A central contribution of this work is the development and application of a new approach that enables this established method to describe quantum states with large, nonlinear fluctuations. Inspired by the study of open quantum systems, we do this by introducing a virtual environment, which continuously measures the system to suppress the growth of quantum fluctuations. This method is successfully applied to the dynamics of a spinor fluid, in which restrictions on the interactions between atoms lead to the formation of a non-equilibrium state with a high degree of quantum entanglement. Finally, the acquired knowledge on spinor fluids is used for their application as a platform for analog gravity. We introduce Hawking radiation emitted by black holes, show that the underlying mechanism is a general property of quantum fields in a flowing background, and apply this analogy to spin waves in a spinor gas. |
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Language
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English
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Publication
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Antwerpen
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Universiteit Antwerpen, Faculteit Wetenschappen
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2024
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DOI
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10.63028/10067/2022500151162165141
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Volume/pages
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xiii, 227 p.
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Note
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Wouters, Michiel [Supervisor]
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Tempere, Jacques [Supervisor]
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Full text (open access)
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