Armando Francesco Borghesani
- Published in print:
- 2007
- Published Online:
- January 2008
- ISBN:
- 9780199213603
- eISBN:
- 9780191707421
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199213603.001.0001
- Subject:
- Physics, Condensed Matter Physics / Materials
In liquid helium, an electron is surrounded by a cavity called an electron bubble of 20 Ångstroms in diameter. A positive helium ion is solvated by an electrostriction induced solid helium-ice shell ...
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In liquid helium, an electron is surrounded by a cavity called an electron bubble of 20 Ångstroms in diameter. A positive helium ion is solvated by an electrostriction induced solid helium-ice shell called a snowball of 7 Ångstroms in diameter. By studying their transport properties, these objects are well suited for the testing of the microscopic properties of superfluidity. At low temperatures and with small electric fields, the drift velocity of the charges depends on their interaction with the elementary excitations of the superfluid: phonons, rotons, and 3He atomic impurities. At higher fields, ions produce quantized vortex rings and vortex lines and studying these sheds light on quantum hydrodynamics. In the fermionic liquid, the 3He isotope ion transport properties display important pieces of information on the coupling of a charge to a Fermi liquid and on the richer topological structure of the superfluid phases appearing at ultralow temperatures. In the normal liquid phases of both isotopes, ions and electrons are used to probe classical hydrodynamics at the λ-transition and at the liquid-vapor transition at which long-range critical fluctuations of the appropriate order parameter occur. Several experiments have investigated the structure of electron bubbles. Electron drift velocity measurements in dense helium gas have elucidated the dynamics of electron bubble formation. This book provides a review of the more than forty-year-long experimental and theoretical research on the transport properties of electrons and ions in liquid and gaseous helium.Less
In liquid helium, an electron is surrounded by a cavity called an electron bubble of 20 Ångstroms in diameter. A positive helium ion is solvated by an electrostriction induced solid helium-ice shell called a snowball of 7 Ångstroms in diameter. By studying their transport properties, these objects are well suited for the testing of the microscopic properties of superfluidity. At low temperatures and with small electric fields, the drift velocity of the charges depends on their interaction with the elementary excitations of the superfluid: phonons, rotons, and 3He atomic impurities. At higher fields, ions produce quantized vortex rings and vortex lines and studying these sheds light on quantum hydrodynamics. In the fermionic liquid, the 3He isotope ion transport properties display important pieces of information on the coupling of a charge to a Fermi liquid and on the richer topological structure of the superfluid phases appearing at ultralow temperatures. In the normal liquid phases of both isotopes, ions and electrons are used to probe classical hydrodynamics at the λ-transition and at the liquid-vapor transition at which long-range critical fluctuations of the appropriate order parameter occur. Several experiments have investigated the structure of electron bubbles. Electron drift velocity measurements in dense helium gas have elucidated the dynamics of electron bubble formation. This book provides a review of the more than forty-year-long experimental and theoretical research on the transport properties of electrons and ions in liquid and gaseous helium.
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/9780199213603.003.0004
- Subject:
- Physics, Condensed Matter Physics / Materials
This chapter introduces the concept of drift mobility and its relationship with the elementary excitations of the superfluid.
This chapter introduces the concept of drift mobility and its relationship with the elementary excitations of the superfluid.
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/9780199213603.003.0001
- Subject:
- Physics, Condensed Matter Physics / Materials
This chapter briefly summarizes the main features of superfluid helium. The Landau velocity criterion for the onset of superfluidity is discussed, and the spectrum of the elementary excitations is ...
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This chapter briefly summarizes the main features of superfluid helium. The Landau velocity criterion for the onset of superfluidity is discussed, and the spectrum of the elementary excitations is shown. A brief introductory description of the structure of electrons and positive He2 + ions in the liquid explains why they are chosen by researchers as probes to test the microscopic properties of superfluidity, and to study quantum hydrodynamics.Less
This chapter briefly summarizes the main features of superfluid helium. The Landau velocity criterion for the onset of superfluidity is discussed, and the spectrum of the elementary excitations is shown. A brief introductory description of the structure of electrons and positive He2 + ions in the liquid explains why they are chosen by researchers as probes to test the microscopic properties of superfluidity, and to study quantum hydrodynamics.
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/9780199213603.003.0006
- Subject:
- Physics, Condensed Matter Physics / Materials
At higher electric fields, the drifting ions are not in thermal equilibrium with the gas of the elementary excitations of the superfluid, and the mobility depends on the field. This chapter presents ...
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At higher electric fields, the drifting ions are not in thermal equilibrium with the gas of the elementary excitations of the superfluid, and the mobility depends on the field. This chapter presents the experimental results of the ion mobility in the superfluid at higher fields and larger temperatures. The field dependence of the mobility is explained in terms of roton scattering in presence of an enhanced roton density around the charge. Emphasis is given on the discovery of the giant mobility discontinuity at which the excess energy is dissipated by ions creating quantized vortex rings. Ions are captured by them and drift together as a new, single unit called a charged vortex ring. The puzzling issue of the drift velocity discontinuities is also addressed.Less
At higher electric fields, the drifting ions are not in thermal equilibrium with the gas of the elementary excitations of the superfluid, and the mobility depends on the field. This chapter presents the experimental results of the ion mobility in the superfluid at higher fields and larger temperatures. The field dependence of the mobility is explained in terms of roton scattering in presence of an enhanced roton density around the charge. Emphasis is given on the discovery of the giant mobility discontinuity at which the excess energy is dissipated by ions creating quantized vortex rings. Ions are captured by them and drift together as a new, single unit called a charged vortex ring. The puzzling issue of the drift velocity discontinuities is also addressed.
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/9780199213603.003.0012
- Subject:
- Physics, Condensed Matter Physics / Materials
Ions and electron bubbles are captured by the vortex lines which occur in a rotating superfluid sample. Once captured, however, the charges can move along the quantized vortex lines. On one hand, ...
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Ions and electron bubbles are captured by the vortex lines which occur in a rotating superfluid sample. Once captured, however, the charges can move along the quantized vortex lines. On one hand, this degree of freedom allows the researcher to use ions to detect the appearance of single, quantized vortex lines. On the other hand, the study of the ion motion along the lines gives important pieces of information on the structure and dynamics of vortices. In fact, the ion motion along the lines is limited by scattering on 3He impurities captured by the vorticity field and by vortex waves, i.e., columnar oscillation of the vortex lines. Experiments and theory of vortex wave-, roton, and 3He impurity scattering on vortex lines are described.Less
Ions and electron bubbles are captured by the vortex lines which occur in a rotating superfluid sample. Once captured, however, the charges can move along the quantized vortex lines. On one hand, this degree of freedom allows the researcher to use ions to detect the appearance of single, quantized vortex lines. On the other hand, the study of the ion motion along the lines gives important pieces of information on the structure and dynamics of vortices. In fact, the ion motion along the lines is limited by scattering on 3He impurities captured by the vorticity field and by vortex waves, i.e., columnar oscillation of the vortex lines. Experiments and theory of vortex wave-, roton, and 3He impurity scattering on vortex lines are described.
VOLOVIK GRIGORY E.
- Published in print:
- 2009
- Published Online:
- January 2010
- ISBN:
- 9780199564842
- eISBN:
- 9780191709906
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199564842.003.0031
- Subject:
- Physics, Condensed Matter Physics / Materials, Particle Physics / Astrophysics / Cosmology
This chapter deals with the properties of the quantum vacuum in superfluids in the presence of the analog of a gravimagnetic field. Such an effective field arises either in the presence of ...
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This chapter deals with the properties of the quantum vacuum in superfluids in the presence of the analog of a gravimagnetic field. Such an effective field arises either in the presence of conventional U(1)-vortices, or under rotation which is equivalent to the constant in the space gravimagnetic field. A quantized vortex in 3He-A is another example of linear topological defects in the vierbein field at which the metric is degenerate. Vortices in superfluid 4He serve as analog of the spinning cosmic string, whose rotational angular momentum is concentrated in the string core. Effective gravimagnetic field concentrated in the core of the vortex produces the Aharonov–Bohm tube with gravimagnetic flux. It gives rise to the Iordanskii force acting on a vortex and to effective frame dragging for quasiparticles. The phenomenon of frame dragging by a rotating body is known as the Lense–Thirring effect. Rotation of or in the vacuum gives rise to Sagnac effect and to quantum friction experienced by a body rotating in the superfluid vacuum. The latter is analog of the Zel'dovich–Starobinsky effect, in which any body rotating in quantum vacuum, including the rotating black hole, radiates and looses its angular momentum. Emission of phonons and rotons from a body rotating in superfluid 4He occurs by quantum tunnelling of these quasiparticles from a body into the ergoregion.Less
This chapter deals with the properties of the quantum vacuum in superfluids in the presence of the analog of a gravimagnetic field. Such an effective field arises either in the presence of conventional U(1)-vortices, or under rotation which is equivalent to the constant in the space gravimagnetic field. A quantized vortex in 3He-A is another example of linear topological defects in the vierbein field at which the metric is degenerate. Vortices in superfluid 4He serve as analog of the spinning cosmic string, whose rotational angular momentum is concentrated in the string core. Effective gravimagnetic field concentrated in the core of the vortex produces the Aharonov–Bohm tube with gravimagnetic flux. It gives rise to the Iordanskii force acting on a vortex and to effective frame dragging for quasiparticles. The phenomenon of frame dragging by a rotating body is known as the Lense–Thirring effect. Rotation of or in the vacuum gives rise to Sagnac effect and to quantum friction experienced by a body rotating in the superfluid vacuum. The latter is analog of the Zel'dovich–Starobinsky effect, in which any body rotating in quantum vacuum, including the rotating black hole, radiates and looses its angular momentum. Emission of phonons and rotons from a body rotating in superfluid 4He occurs by quantum tunnelling of these quasiparticles from a body into the ergoregion.
Lev Pitaevskii and Sandro Stringari
- Published in print:
- 2016
- Published Online:
- March 2016
- ISBN:
- 9780198758884
- eISBN:
- 9780191818721
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198758884.003.0021
- Subject:
- Physics, Condensed Matter Physics / Materials
This chapter discusses the behaviour of quantum mixtures, including spinor gases. It considers mixtures of different atomic species and discuss the conditions for miscibility and the role of the ...
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This chapter discusses the behaviour of quantum mixtures, including spinor gases. It considers mixtures of different atomic species and discuss the conditions for miscibility and the role of the interspecies interaction concerning both the equilibrium and the dynamic properties of the mixture. The inclusion of Rabi coupling between different spin states and the consequences of blocking the relative phase of two condensates are discussed. The chapter also considers the realization of artificial gauge fields using spin-orbit coupling induced by Raman transitions, and it investigates the nature of the new emerging quantum phases and their dynamic behaviour, including the occurrence of a characteristic rotonic structure and of stripes. Finally, the nature of quantum mixtures of bosons and fermions is discussed.Less
This chapter discusses the behaviour of quantum mixtures, including spinor gases. It considers mixtures of different atomic species and discuss the conditions for miscibility and the role of the interspecies interaction concerning both the equilibrium and the dynamic properties of the mixture. The inclusion of Rabi coupling between different spin states and the consequences of blocking the relative phase of two condensates are discussed. The chapter also considers the realization of artificial gauge fields using spin-orbit coupling induced by Raman transitions, and it investigates the nature of the new emerging quantum phases and their dynamic behaviour, including the occurrence of a characteristic rotonic structure and of stripes. Finally, the nature of quantum mixtures of bosons and fermions is discussed.
Lev Pitaevskii and Sandro Stringari
- Published in print:
- 2016
- Published Online:
- March 2016
- ISBN:
- 9780198758884
- eISBN:
- 9780191818721
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198758884.003.0008
- Subject:
- Physics, Condensed Matter Physics / Materials
This chapter summarizes some key features exhibited by superfluid 4He. These include the structure of the elementary excitations exhibiting the typical phonon–maxon–roton dispersion, the pair ...
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This chapter summarizes some key features exhibited by superfluid 4He. These include the structure of the elementary excitations exhibiting the typical phonon–maxon–roton dispersion, the pair correlation function, the nature of quantized vortices, and some key thermodynamic properties like the behaviour of the specific heat and the temperature dependence of the normal density. Emphasis is also given to the behaviour of the momentum distribution, extracted from the analysis of the dynamic structure factor at high wave vectors and the experimental evidence for the condensate fraction as a function of temperature and pressure. A comparison between experiments and theoretical predictions based on Monte Carlo simulations is also presented.Less
This chapter summarizes some key features exhibited by superfluid 4He. These include the structure of the elementary excitations exhibiting the typical phonon–maxon–roton dispersion, the pair correlation function, the nature of quantized vortices, and some key thermodynamic properties like the behaviour of the specific heat and the temperature dependence of the normal density. Emphasis is also given to the behaviour of the momentum distribution, extracted from the analysis of the dynamic structure factor at high wave vectors and the experimental evidence for the condensate fraction as a function of temperature and pressure. A comparison between experiments and theoretical predictions based on Monte Carlo simulations is also presented.
