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Last update: KFNTLS/MFF.CUNI.CZ (29.04.2008)
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Last update: KFNTLS/MFF.CUNI.CZ (29.04.2008)
The aim of the course is to explain basic principles of the Bose - Einstein condensation in 3d momentum space. The accent is on experiments that unequivocally confirm this phenomenon, and on physical properties of superfluid phases of 3He and 4He. |
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Last update: doc. RNDr. Vojtěch Chlan, Ph.D. (12.06.2019)
Zkouška probíhá ústní formou. Požadavky ke zkoušce odpovídejí sylabu předmětu v rozsahu, který byl prezentován na přednášce. |
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Last update: T_KFNT (02.05.2003)
Basic properties of 4 He and 3He, liquifaction of 4He, Fermi-Dirac and Bose - Einstein quantum statistics. Ideal Bose gas, Bose - Einstein condensation (BEC). Ideal Fermi gas, Fermi liquid, zero sound. Phase diagrams of 4He a 3He, zero oscillations. 3He-4He mixtures, dilution refrigerator.
Superfluid He II - Fountain effect, mechano-caloric effect. Andronikashvili experiment, two-fluid model and Landau equations of motion, energy spectrum, criterion of superfluidity. Superfluid film. Collective modes - first, second, third and fourth sounds. Macroscopic wave function, quantization of circulation - quantized vortices, mutual friction, Kelvin and Tkachenko waves, introduction into superfluid hydrodynamics, superfluid turbulence. Positive and negative ions, ionic mobility, two-dimensional pools of ions below the surface of superfluid helium, plasma oscillations, crystallization.
Superfluid 3He - basic ideas of generalized BCS theory, paramagnons, equal spin pairing, order parameter for the A, B, and A1 phases. Textures and orienting forces, solitons. Nuclear magnetic resonance. Phase-slips and Josephson phenomena in 3He. Rotating 3He- continuous and singular vortices. Superfluid hydrodynamics in 3He, Kelvin-Helmholtz instability, transition to superfluid turbulence. Relationship between superfluidity and cosmology, Kibble-Zurek mechanism.
BEC - hydrogen, alcali atoms, experiments, principles of laser cooling, BEC and superfluidity. Quantized vortices in BEC. |