Fast Relaxation Phenomena in Extended Thermodynamics of Superfluids

Mongiovı̀, Maria Stella; Peruzza, R.A.

doi:10.1142/9789812777331_0041

Cited by 2 publications

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“…Recently the extended irreversible thermodynamics has been applied to describe He-I and He-II 12,13 . It is shown that the behavior of helium II can be described by means of an extended thermodynamic theory where four fields, namely density, temperature, velocity, and heat flux are involved as independent fields.…”

Section: Extended Irreversible Thermodynamicsmentioning

confidence: 99%

Quantum fluids in nanoporous media—Effects of the confinement and fractal geometry

Tayurskiı̆

Lysogorskiy

2011

Chin. Sci. Bull.

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The complex behavior of such quantum fluids like liquid 4 He and liquid 3 He in nanoporous media is determined by spatial quantization because of geometrical confinement as well as by significant contribution from the surface atoms. In the present report we will review the procedure, results and discuss the issues for fractionalized nonextensive hydrodynamical approach to describe the properties of quantum fluids inside nanopores and propose consideration of strong correlated quantum liquid by means of fractionalized Schrödinger equation. The zero-point energy of atoms of two stable isotopes of helium -4 He and 3 He -is high enough to prevent their solidification even at extremely low temperatures without application of external pressure. So they belong to the class of quantum fluids with strong correlations between atoms but their behavior is quite different at low temperatures. The first one represents a Bose-system and shows superfluid transition at 2.17 K while atoms of 3 He are governed by Fermi-statistics and superfluid transition can be observed only at much lower temperatures (about 1 mK) when the pairing of two atoms occurs. But even at liquid helium temperatures (1.5-4.2 K) the effects of quantum statistics for 3 He atoms become pronounceable especially in nanoscale confinement (nanoporous media, thin adsorbed layers on solid substrates) [1][2][3] and in the presence of nanoscale disorder induced for example by silica aerogel strands [4]. In recent years the problem of correct description of quantum fluids in the confined geometry at nanoscale length has emerged [5][6][7][8]. It has been recognized that the quantum fluids at these circumstances can be considered as a new state of quantum matter due to close values between characteristic lengths for these quantum liquids and the size of geometrical confinement and significant contri- *Corresponding author (email: dtayursk@gmail.com) bution from the surface atoms. So one has to apply new physics to describe such systems with taking into account their complex nature. For example, last two years the attempts to develop the fractionalized two-fluid hydrodynamics for nanoporous media with fractal dimensions have been made [9,10]. The actuality of such new hydrodynamics becomes very clear because of numerous studies of quantum liquids inside nanoporous media [11,12] as well as because of last developments in chemical synthesis of aerogels with different network of strands (from fibrous to globular one [13]). One of the interesting obtained results is that density waves (the first sound) and temperature waves (the second sound) become strongly coupled even in the absence of viscosity, so it is purely geometric effect of fractal space of nanopores [9,10]. In this paper we will review the procedure, results and discuss the issues for this approach. Theoretical models for bulk superfluid helium-4There are several approaches to describe the behavior of bulk superfluid helium-4. For example, two-fluid model [14,15],

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Section: Extended Irreversible Thermodynamicsmentioning

confidence: 99%

Quantum fluids in nanoporous media—Effects of the confinement and fractal geometry

Tayurskiı̆

Lysogorskiy

2011

Chin. Sci. Bull.

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“…In this way, a linear macroscopic one-fluid model of liquid helium II, based on Extended Thermodynamics [8,9], has been formulated [7]. This model is able to describe the laminar flow of the superfluid both in the presence and in absence of dissipative phenomena and to predict the propagation of the two sounds in bulk liquid helium II and of the fourth sound in liquid helium flowing in a porous medium [7], [10]- [13], in agreement with microscopic and experimental data.…”

Section: Evolution Equationsmentioning

confidence: 99%

Waves propagation in turbulent superfluid helium in presence of combined rotation and counterflow

Peruzza

Sciacca

2007

Physica B: Condensed Matter

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A complete study of the propagation of waves (namely longitudinal density and temperature waves, longitudinal and transversal velocity waves and heat waves) in turbulent superfluid helium is made in three situations: a rotating frame, a thermal counterflow, and the simultaneous combination of thermal counterflow and rotation. Our analysis aims to obtain as much as possible information on the tangle of quantized vortices from the wave speed and attenuation factor of these different waves, depending on their relative direction of propagation with respect to the rotation vector. PACS number(s): 05.70.Ln, 67.40.Vs, 67.40.Bz, 47.27.2i A.M.S. Classification: 82D50

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Fast Relaxation Phenomena in Extended Thermodynamics of Superfluids

Cited by 2 publications

References 0 publications

Quantum fluids in nanoporous media—Effects of the confinement and fractal geometry

Quantum fluids in nanoporous media—Effects of the confinement and fractal geometry

Waves propagation in turbulent superfluid helium in presence of combined rotation and counterflow

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