Singlet Diatomic Potential Electron Spins AntiParallel B B
Настройка взаимодействия с помощью резонанса Фано – Фешбаха Singlet Diatomic Potential: Electron Spins Anti-Parallel B B B Triplet Diatomic Potential: Electron Spins Parallel
Резонанс Фешбаха: длина рассеяния a в зависимсти от магнитного поля @ 528 G 840 G *generated using formula published in Bartenstein, et al, PRL 94 103201 (2005)
Плавный переход от ферми-газа к бозе-газу молекул Li 2 Singlet Diatomic Potential: Electron Spins Anti-Parallel Triplet Diatomic Potential: Electron Spins Parallel Ферми-газ атомов Li → Бозе-газ молекул Li 2
Сильное взаимодействие. Универсальность L Сильное взаимодействие: R -V 0 Theory: Carlson (2003) b = - 0. 560, Strinati (2004) b = - 0. 545 Experiment (sound propagation, Duke): b = - 0. 565(. 015)
Experimental Apparatus
Experimental Apparatus
Trap for strongly-interacting atoms C , 60 r e s a O 2 l W Laser (60 W): l=10. 6 mm Atoms (Li): l=670 nm Negligible optical heating Scattering = 1 photon / 30 min
Cooling to degeneracy (T<EF) Switch collisions on & evaporate: from 150 m. K to ~100 n. K (from r=10 -5 to ~1)
Absorptive Imaging 300 mm
Распространиние звука в облаке Sound excitation: Slice of green light (pulsed) Trapped atoms Observation: hold, release & image thold=0
Sound propagation
Sound propagation
Sound speed at T<<EF in the BCS to BEC crossover
The team at Duke Ingrid Kaldre Bason Clancy John Thomas Joe Kinast Le Luo James Joseph
The team in Nizhniy Novgorod
Sound speed at T<<EF in the BCS to BEC crossover
Thermodynamics: How to measure entropy of a strongly-interacting gas
Entropy per particle (S/N) vs Energy per particle MC calculation: Bulgac et al (ar. Xiv, 2007)
Entropy per particle (S/N) vs Energy per particle Transition Ec=0. 94 EF
Fits for S/N vs E/EF
Energy measured from the cloud size !! In a universal Fermi system: pressure [Ho, PRL (2004)] Trap potential U z Local energy density (interaction + kinetic) Force Balance: Virial Theorem: Thomas et. al. (Duke), PRL (2005)
Measure S vs E using adiabatic magnetic field sweep: measure entropy at 1200 G measure energy *generated using formula published in Bartenstein, et al, PRL 94 103201 (2005)
- Slides: 50