並列タイトル等Controlling Superfluid and Insulating States in Interacting Quantum Gases
授与機関名Okinawa Institute of Science and Technology Graduate University
一般注記In this thesis, I present two studies on controlling the state and properties of both single-species and composite quantum gases by tuning the various interaction strengths. In the first work, I derive a shortcut to adiabaticity (STA) for tuning a Feshbach resonance in repulsively interacting Bose-Einstein condensates (BECs) in the ThomasFermi regime. This shortcut mimics an adiabatic evolution and allows one to compress and expand a BEC without friction within an almost arbitrarily short time interval. I then use this technique to show how it can boost the performance of the so-called Feshbach quantum engine and also determine its limits and the instabilities it can lead to. The first part is complemented by a study demonstrating the general ineffectiveness of STAs as a tool to increase the attainable precision in critical quantum metrology at the example of two critical toy models. In the second part, I show that a strongly correlated one-dimensional quantum gas in the Tonks-Girardeau (TG) limit that is immersed into a BEC can undergo a transition to a crystal-like insulator state without any externally imposed lattice potential. I develop a model that accurately describes the system in the pinned insulator state, even if the TG gas has a finite temperature. Additionally, I study the superfluid state that can persist in the gas for finite interactions away from the TG limit and uncover the full phase diagram of the system.
コレクション(個別)国立国会図書館デジタルコレクション > デジタル化資料 > 博士論文
受理日(W3CDTF)2022-10-11T11:55:44+09:00
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