A.F. Borghesani
- Published in print:
- 2007
- Published Online:
- January 2008
- ISBN:
- 9780199213603
- eISBN:
- 9780191707421
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199213603.003.0005
- Subject:
- Physics, Condensed Matter Physics / Materials
This chapter describes the main experimental techniques used to measure the drift velocity in superfluid 4He at low temperature. The experimental results are then presented by showing the ...
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This chapter describes the main experimental techniques used to measure the drift velocity in superfluid 4He at low temperature. The experimental results are then presented by showing the contributions to the ion drag due to the different elementary excitations of the superfluid. The theoretical description of the processes of ion scattering off phonons, rotons, and 3He atomic impurities is also presented, and the theoretical predictions are compared with experimental results. The use of the formalism of the Boltzmann transport equation to predict how the drag force on an ion in the superfluid is determined by the different scattering mechanisms is discussed.Less
This chapter describes the main experimental techniques used to measure the drift velocity in superfluid 4He at low temperature. The experimental results are then presented by showing the contributions to the ion drag due to the different elementary excitations of the superfluid. The theoretical description of the processes of ion scattering off phonons, rotons, and 3He atomic impurities is also presented, and the theoretical predictions are compared with experimental results. The use of the formalism of the Boltzmann transport equation to predict how the drag force on an ion in the superfluid is determined by the different scattering mechanisms is discussed.
A.F. Borghesani
- Published in print:
- 2007
- Published Online:
- January 2008
- ISBN:
- 9780199213603
- eISBN:
- 9780191707421
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199213603.003.0021
- Subject:
- Physics, Condensed Matter Physics / Materials
This chapter discusses the studies of the electron bubble mobility in normal liquid 3He. The high temperature measurements are extended into the milliKelvin range down to the superfluid transition at ...
More
This chapter discusses the studies of the electron bubble mobility in normal liquid 3He. The high temperature measurements are extended into the milliKelvin range down to the superfluid transition at approximately 2.7 mK. At such low temperatures, the mean free path of the quasiparticles of the liquid becomes larger than the size of the electron bubble, and the drag on them must be calculated in the Knudsen limit. A quantum modification of the Boltzmann transport equation has been used to describe theoretically the experimental results by taking into account the requirements of the Pauli exlusion principle for fermion scattering. It is shown that the ion recoil must be taken into account by means of the van Hove scattering functions.Less
This chapter discusses the studies of the electron bubble mobility in normal liquid 3He. The high temperature measurements are extended into the milliKelvin range down to the superfluid transition at approximately 2.7 mK. At such low temperatures, the mean free path of the quasiparticles of the liquid becomes larger than the size of the electron bubble, and the drag on them must be calculated in the Knudsen limit. A quantum modification of the Boltzmann transport equation has been used to describe theoretically the experimental results by taking into account the requirements of the Pauli exlusion principle for fermion scattering. It is shown that the ion recoil must be taken into account by means of the van Hove scattering functions.
