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Fluctuations and correlations in ultracold Fermi gases
| Content Provider | Semantic Scholar |
|---|---|
| Author | Meineke, Jan Jakob |
| Copyright Year | 2012 |
| Abstract | In this thesis we present the first in-situ measurement of densityand spin-fluctuations in trapped ultracold Fermi gases with a spatial resolution on the intrinsic scale set by the Fermi wavelength. The measurement of the fluctuations gives direct experimental access to the correlation functions underlying the many-body properties of strongly interacting systems. Using high-resolution imaging, we have observed the suppression of the density fluctuations below atomic shot-noise in quantum-degenerate, weakly interacting Fermi gases. This suppression is as a consequence of the quantum statistics obeyed by indistinguishable fermions and constitutes a measurement of antibunching in real space. We have also demonstrated a new method for measuring the temperature of trapped ultracold gases that is applicable also for strongly interacting system and which is based on the fluctuationdissipation theorem. For our measurement of the spin-fluctuations we have developed a shot-noise limited interferometer, which maps the spin-polarization of the atoms to a single mode of the light field. With this method we have studied the spin-fluctuations in weakly and strongly interacting two-component Fermi gases in a spatially resolved and quantitative way. For a strongly interacting gas we have measured a reduction of the spin-fluctuations due to pairing by 9.4 dB. We have used the spin-fluctuations to determine the spin-susceptibility. Furthermore, we interpret our measurement of the spin-fluctuations as a macroscopic entanglement witness, opening the way towards experimental investigations of entanglement in many-body systems. In a complimentary approach, we have achieved the first conduction measurement with cold atoms by engineering macroscopic atom reservoirs connected by a narrow channel. Using high-resolution imaging and manipulation of the atoms, we have demonstrated the emergence of a contact resistance, where the reservoirs and the channel connect. These measurements open the way towards the quantum simulation of mesoscopic devices. |
| File Format | PDF HTM / HTML |
| DOI | 10.3929/ethz-a-007580148 |
| Alternate Webpage(s) | https://www.research-collection.ethz.ch/bitstream/handle/20.500.11850/58478/eth-6287-01.pdf?isAllowed=y&sequence=1 |
| Alternate Webpage(s) | https://www.research-collection.ethz.ch/bitstream/handle/20.500.11850/58478/eth-6287-02.pdf?isAllowed=y&sequence=2 |
| Alternate Webpage(s) | https://www.research-collection.ethz.ch/bitstream/handle/20.500.11850/58478/eth-6287-01.pdf;jsessionid=62B62ECA7B4F441905D3D07F3B040F81?sequence=1 |
| Alternate Webpage(s) | https://www.research-collection.ethz.ch/bitstream/handle/20.500.11850/58478/eth-6287-01.pdf;jsessionid=9C88A38F8002F6A837A369A910BB040C?sequence=1 |
| Alternate Webpage(s) | https://www.research-collection.ethz.ch/bitstream/handle/20.500.11850/58478/eth-6287-02.pdf |
| Alternate Webpage(s) | https://www.research-collection.ethz.ch/bitstream/handle/20.500.11850/58478/eth-6287-01.pdf;jsessionid=4A7879EFD39DF3DFA91D029E3B2CB15E?sequence=1 |
| Alternate Webpage(s) | https://doi.org/10.3929/ethz-a-007580148 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
