Log in

Relevant bibliographies by topics / SUPERFLUID MODEL / Journal articles

To see the other types of publications on this topic, follow the link: SUPERFLUID MODEL.

Journal articles on the topic 'SUPERFLUID MODEL'

Author: Grafiati

Published: 4 June 2021

Last updated: 12 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'SUPERFLUID MODEL.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Kwon, W. J., G. Del Pace, R. Panza, M. Inguscio, W. Zwerger, M. Zaccanti, F. Scazza, and G. Roati. "Strongly correlated superfluid order parameters from dc Josephson supercurrents." Science 369, no. 6499 (July 2, 2020): 84–88. http://dx.doi.org/10.1126/science.aaz2463.

Full text

Abstract:

The direct-current (dc) Josephson effect provides a phase-sensitive tool for investigating superfluid order parameters. We report on the observation of dc Josephson supercurrents in strongly interacting fermionic superfluids across a tunneling barrier in the absence of any applied potential difference. For sufficiently strong barriers, we observed a sinusoidal current-phase relation, in agreement with Josephson’s seminal prediction. We mapped out the zero-resistance state and its breakdown as a function of junction parameters, extracting the Josephson critical current behavior. By comparing our results with an analytic model, we determined the pair condensate fraction throughout the Bardeen-Cooper-Schrieffer–Bose-Einstein condensation crossover. Our work suggests that coherent Josephson transport may be used to pin down superfluid order parameters in diverse atomic systems, even in the presence of strong correlations.

APA, Harvard, Vancouver, ISO, and other styles

2

AGUIRRE, R. M. "NUCLEAR MATTER SUPERFLUIDITY IN AN EFFECTIVE HADRONIC FIELD MODEL WITH EXCLUDED VOLUME CORRECTIONS." International Journal of Modern Physics E 20, no. 09 (September 2011): 1967–82. http://dx.doi.org/10.1142/s0218301311019611.

Full text

Abstract:

Properties of the 1S0 superfluid phase are studied for symmetric nuclear matter at finite temperature. It is described within a covariant hadronic field model, of the σ–ω type, with addition of density dependent correlations simulating effects due to finite extension of nucleons. The model is solved in a self-consistent Hartree–Bogoliubov approach, assuming instantaneous interactions in the superfluid phase. A comparison with the results obtained from several hadronic field models is made. Main characteristics of our description of the superfluid gap are in qualitative agreement with some studies using microscopic potentials, although further refinements could improve its performance.

APA, Harvard, Vancouver, ISO, and other styles

3

Saadat, H., and B. Pourhassan. "Holographic Superfluid and STU Model." International Journal of Theoretical Physics 52, no. 3 (November 11, 2012): 997–1006. http://dx.doi.org/10.1007/s10773-012-1412-3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

OWCZAREK, ROBERT. "KNOTTED VORTICES AND SUPERFLUID PHASE TRANSITION." Modern Physics Letters B 07, no. 23 (October 10, 1993): 1523–26. http://dx.doi.org/10.1142/s0217984993001557.

Full text

Abstract:

In this letter, studies of knotted vortex structures in superfluid helium are continued. A model of superfluid phase transition (λ-transition) is built in this framework. Similarities of this model to the two-dimensional Ising model are shown. Dependence of specific heat of superfluid helium on temperature near the λ point is explained.

APA, Harvard, Vancouver, ISO, and other styles

5

GU, SHI-JIAN, JUNPENG CAO, SHU CHEN, and HAI-QING LIN. "SCALING LAW OF SUPERFLUID–INSULATOR TRANSITION IN THE 1D BOSE–HUBBARD MODEL." International Journal of Modern Physics B 26, no. 04 (February 10, 2012): 1250014. http://dx.doi.org/10.1142/s0217979211102228.

Full text

Abstract:

The finite size scaling behavior of superfluid–insulator transition in the one-dimensional Bose–Hubbard model is studied. It is shown that the superfluid density of the system with finite size has a maximum at a certain interaction Um and the derivative of superfluid density has a minimum at a certain interaction Ud. The critical point Uc can be quantified by the scaling analysis of either Um or Ud. The transition point Um tends to the critical point Uc from the region of U < Uc, while the Ud tends to the Uc from the region of U > Uc. The transition points Um and Ud satisfy different finite size scaling laws and have the different critical exponents. The divergence speed of the superfluid density is much smaller than that of its derivative at the critical point.

APA, Harvard, Vancouver, ISO, and other styles

6

Haskell, B., D. Antonopoulou, and C. Barenghi. "Turbulent, pinned superfluids in neutron stars and pulsar glitch recoveries." Monthly Notices of the Royal Astronomical Society 499, no. 1 (September 4, 2020): 161–70. http://dx.doi.org/10.1093/mnras/staa2678.

Full text

Abstract:

ABSTRACT Pulsar glitches offer an insight into the dynamics of superfluids in the high-density interior of a neutron star. To model these phenomena, however, one needs to have an understanding of the dynamics of a turbulent array of superfluid vortices moving through a pinning lattice. In this paper, we develop a theoretical approach to describe vortex-mediated mutual friction in a pinned, turbulent and rotating superfluid. Our model is then applied to the study of the post-glitch rotational evolution in the Vela pulsar and in PSR J0537-6910. We show that in both cases a turbulent model fits the evolution of the spin frequency derivative better than a laminar one. We also predict that the second derivative of the frequency after a glitch should be correlated with the waiting time since the previous glitch, which we find to be consistent with observational data for these pulsars. The main conclusion of this paper is that in the post-glitch rotational evolution of these two pulsars we are most likely observing the response to the glitch of a pinned turbulent region of the star (possibly the crust) and not the laminar response of a regular straight vortex array.

APA, Harvard, Vancouver, ISO, and other styles

7

Ho, Wynn C. G., Cristóbal M. Espinoza, Danai Antonopoulou, and Nils Andersson. "Pinning down the superfluid and measuring masses using pulsar glitches." Science Advances 1, no. 9 (October 2015): e1500578. http://dx.doi.org/10.1126/sciadv.1500578.

Full text

Abstract:

Pulsars are known for their superb timing precision, although glitches can interrupt the regular timing behavior when the stars are young. These glitches are thought to be caused by interactions between normal and superfluid matter in the crust of the star. However, glitching pulsars such as Vela have been shown to require a superfluid reservoir that greatly exceeds that available in the crust. We examine a model in which glitches tap the superfluid in the core. We test a variety of theoretical superfluid models against the most recent glitch data and find that only one model can successfully explain up to 45 years of observational data. We develop a new technique for combining radio and x-ray data to measure pulsar masses, thereby demonstrating how current and future telescopes can probe fundamental physics such as superfluidity near nuclear saturation.

APA, Harvard, Vancouver, ISO, and other styles

8

Rahmatinejad, A., R. Razavi, and L. Elahizadeh. "First-order phase transition in 97,98Mo isotopes." Modern Physics Letters A 36, no. 19 (June 21, 2021): 2150133. http://dx.doi.org/10.1142/s0217732321501339.

Full text

Abstract:

Experimental evidences of a first-order phase transition from a superfluid to a non-interacting Fermi gas system are studied for [Formula: see text]Mo isotopes. The experimental observations are compared with the semi-empirical macroscopic model and superfluid formalism. We have shown that the entropy excess ratio introduced in our previous publications within the superfluid model can describe the first-order phase transition due to pair-breaking in atomic nuclei.

APA, Harvard, Vancouver, ISO, and other styles

9

Czart, W. R., M. Szkudlarek, and S. Robaszkiewicz. "Superfluid Characteristics of Induced-Pairing Model." Acta Physica Polonica A 91, no. 2 (February 1997): 415–18. http://dx.doi.org/10.12693/aphyspola.91.415.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Ovchinnikov, M., and Alexey Novikov. "Microscopic computational model of a superfluid." Journal of Chemical Physics 132, no. 21 (June 7, 2010): 214101. http://dx.doi.org/10.1063/1.3424846.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

MARQUES, G. C. "MICROSCOPIC MODEL OF SUPERFLUID HELIUM-4." International Journal of Modern Physics B 08, no. 11n12 (May 30, 1994): 1577–624. http://dx.doi.org/10.1142/s0217979294000683.

Full text

Abstract:

To understand the properties of superfluid Helium-4 we propose a microscopic model for the description of this imperfect boson gas at very low temperatures. This microscopic theory contains only two parameters that are inferred from the He-He interaction potential. The understanding of the properties of Helium-4 in the super-fluid phase is based on Bose-Einstein condensation and for its description we use field theory at finite temperatures. We get a large number of characteristic features of superfluidity. Among these features we get phonon and roton spectrum, the two-fluid component description and London’s relation. We have also made predictions for twelve physically relevant quantities for He-4 below the λ-point. The predictions of the model were made by using the loop expansion in field theory. We find that our predictions are in reasonable agreement with the experimental results.

APA, Harvard, Vancouver, ISO, and other styles

12

Sokalski, K. "Superfluid model of high temperature superconductivity." Physica C: Superconductivity 161, no. 2 (November 1989): 233–38. http://dx.doi.org/10.1016/0921-4534(89)90136-6.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Šorli, Amrit S., and Štefan Čelan. "Time-Invariant Superfluid Quantum Space as the Unified Field Theory." Reports in Advances of Physical Sciences 04, no. 03 (September 2020): 2050007. http://dx.doi.org/10.1142/s2424942420500073.

Full text

Abstract:

The novelty of 21st-century physics is the development of the “superfluid quantum vacuum” model, also named “superfluid quantum space” that is replacing space-time as the fundamental arena of the universe. It also represents the model that has the potential of unifying four fundamental forces of the universe. Superfluid quantum space is represented as the time-invariant fundamental field of the universe where time is merely the duration of material changes.

APA, Harvard, Vancouver, ISO, and other styles

14

KIVOTIDES, DEMOSTHENES. "Spreading of superfluid vorticity clouds in normal-fluid turbulence." Journal of Fluid Mechanics 668 (December 16, 2010): 58–75. http://dx.doi.org/10.1017/s0022112010004659.

Full text

Abstract:

In this paper, we formulate a self-consistent model of thermal superfluid dynamics. By solving it, we analyse the problem of superfluid vorticity cloud propagation in normal-fluid turbulence. We show that superfluid cloud expansion is driven by pattern-forming superfluid vortex instabilities taking place in the interface layer between the cloud's bulk and the outer undisturbed normal-fluid turbulence. The radius of the cloud increases linearly with time. Mutual friction transfers energy from the normal-fluid turbulence to the superfluid cloud, whilst damping the smallest normal-fluid turbulence motions. This damping action is much weaker than viscous dissipation effects in a corresponding pure normal-fluid turbulence. The energy spectrum of superfluid turbulence presents the k−3 scaling that characterizes the spiral superfluid vorticity patterns of normal vortex tube–superfluid vortex interactions. The corresponding k−2 pressure spectrum signifies the singular nature of superfluid vorticity. These two scalings coincide in wavenumber space with the Kolmogorov regime in the normal-fluid turbulence. We compute a fractal dimension df ≈ 1.652 for superfluid vorticity. Due to simpler underlying superfluid vortex dynamics in relation to the strongly nonlinear classical vortex dynamics, this fractal dimension is smaller than the corresponding dimension of vortex tube centrelines in classical turbulence.

APA, Harvard, Vancouver, ISO, and other styles

15

Sheshadri, K. "Localization in the Hopping Disordered Bose Hubbard Model." Modern Physics Letters B 12, no. 28 (December 10, 1998): 1159–66. http://dx.doi.org/10.1142/s0217984998001360.

Full text

Abstract:

The zero-temperature superfluid (SF)–Bose glass (BG) transition in the strongly correlated (U=∞) Bose Hubbard model in d dimensions driven by disorder in hopping is studied using a simple analytic technique. The transition is identified as the point at which the density of states for local rotations of phase of the superfluid order parameter is enhanced at the lowest energies. This identification leads to the values ν=2/d and z=d/2 for the correlation length and dynamical exponents, respectively, by an approximation calculation of the low-energy density of states for large d. At the transition, the singular part of the compressibility κ vanishes, so κ is finite.

APA, Harvard, Vancouver, ISO, and other styles

16

Huang, Wung-Hong. "Landau free energy and analytic tricritical point in holographic superfluid." International Journal of Modern Physics A 30, no. 07 (March 5, 2015): 1550035. http://dx.doi.org/10.1142/s0217751x15500359.

Full text

Abstract:

We investigate the analytical method in studying the holographic superfluid model which is described by Maxwell field minimally coupling to a charged scalar field in a fixed AdS black hole background. We propose a method that enables us to find exact value of coefficient in the solution and thus obtain higher-order expansion of the associated Landau free energy of the holographic superfluid with flow. We determine the critical value of superfluid velocity at the tricritical point of holographic superfluid and compare it with the numerical value.

APA, Harvard, Vancouver, ISO, and other styles

17

Halperin, W. P. "Superfluid 3He in Aerogel." Annual Review of Condensed Matter Physics 10, no. 1 (March 10, 2019): 155–70. http://dx.doi.org/10.1146/annurev-conmatphys-031218-013134.

Full text

Abstract:

Superfluid 3He is an unconventional neutral superfluid in a p-wave state with three different superfluid phases, each identified by a unique set of characteristic broken symmetries and nontrivial topology. Despite natural immunity of 3He from defects and impurity of any kind, it has been found that they can be artificially introduced with high-porosity silica aerogel. Furthermore, it has been shown that this modified quantum liquid becomes a superfluid with remarkably sharp thermodynamic transitions from the normal state and between its various phases. These phases include new superfluid phases that are stabilized by anisotropy from uniform strain imposed on the silica aerogel framework, and they include new phenomena in a new class of anisotropic aerogels consisting of nematically ordered alumina strands. The study of superfluid 3He in the presence of correlated, quenched disorder from aerogel serves as a model for understanding the effect of impurities on the symmetry and topology of unconventional superconductors.

APA, Harvard, Vancouver, ISO, and other styles

18

DAVIS, R. L. "SUPERFLUID FIELD THEORY." International Journal of Modern Physics A 08, no. 28 (November 10, 1993): 5005–21. http://dx.doi.org/10.1142/s0217751x9300196x.

Full text

Abstract:

The very low temperature dynamics of an isotropic superfluid is derived from a repulsive bosonic field theory. The field theory is a fully dynamical generalization of the Ginzburg-Landau theory, which at zero temperature has semiclassical superfluid solutions. It is shown that supercurrent quenching occurs above some intrinsic critical velocity. The speed of first sound is calculated and the Landau criterion for a maximum superfluid velocity is derived. At finite temperature, the thermodynamic potential is computed, the order parameter and gap equations are derived, the origin of the Landau two-fluid model is identified and the thermomechanical effect is explained. This theory successfully describes many of the features of 4He well below the critical temperature, as well as relativistic generalizations.

APA, Harvard, Vancouver, ISO, and other styles

19

Gavassino, Lorenzo, Marco Antonelli, and Brynmor Haskell. "Superfluid Dynamics in Neutron Star Crusts: The Iordanskii Force and Chemical Gauge Covariance." Universe 7, no. 2 (January 29, 2021): 28. http://dx.doi.org/10.3390/universe7020028.

Full text

Abstract:

We present a geometrical derivation of the relativistic dynamics of the superfluid inner crust of a neutron star. The resulting model is analogous to the Hall-Vinen-Bekarevich-Khalatnikov hydrodynamics for a single-component superfluid at finite temperature, but particular attention should be paid to the fact that some fraction of the neutrons is locked to the motion of the protons in nuclei. This gives rise to an ambiguity in the definition of the two currents (the normal and the superfluid one) on which the model is built, a problem that manifests itself as a chemical gauge freedom of the theory. To ensure chemical gauge covariance of the hydrodynamic model, the phenomenological equation of motion for a quantized vortex should contain an extra transverse force, that is the relativistic version of the Iordanskii force discussed in the context of superfluid Helium. Hence, we extend the mutual friction model of Langlois et al. (1998) to account for the possible presence of this Iordanskii-like force. Furthermore, we propose that a better understanding of the (still not completely settled) controversy around the presence of the Iordanskii force in superfluid Helium, as well as in neutron stars, may be achieved by considering that the different incompatible results present in the literature pertain to two, opposite, dynamical regimes of the fluid system.

APA, Harvard, Vancouver, ISO, and other styles

20

Gold, A. "Superfluid-insulator transition in the Bogoliubov model." Physical Review Letters 70, no. 10 (March 8, 1993): 1563. http://dx.doi.org/10.1103/physrevlett.70.1563.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Hänninen, R., T. Setälä, and E. V. Thuneberg. "Homogeneous scattering model for impure superfluid 3He." Physica B: Condensed Matter 255, no. 1-4 (December 1998): 11–18. http://dx.doi.org/10.1016/s0921-4526(98)00450-5.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Zimanyi, G. T., P. A. Crowell, R. T. Scalettar, and G. G. Batrouni. "Bose-Hubbard model and superfluid staircases inHe4films." Physical Review B 50, no. 9 (September 1, 1994): 6515–18. http://dx.doi.org/10.1103/physrevb.50.6515.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Carlson, Neil N. "A topological defect model of superfluid vortices." Physica D: Nonlinear Phenomena 98, no. 1 (November 1996): 183–200. http://dx.doi.org/10.1016/0167-2789(96)00052-8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Dumitrescu, O., and M. Horoi. "An enlarged superfluid model of atomic nucleus." Il Nuovo Cimento A 103, no. 5 (May 1990): 653–68. http://dx.doi.org/10.1007/bf02789018.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Schäfer, R., and T. Fliessbach. "The two-fluid model with superfluid entropy." Il Nuovo Cimento D 16, no. 4 (April 1994): 373–90. http://dx.doi.org/10.1007/bf02451645.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Luo, Xin-Lian, Qiu-He Peng, Ming Zhang, and Chih-Kang Chou. "Pulsar Spin-Down by 3P2 Superfluid Neutrons." Symposium - International Astronomical Union 214 (2003): 175–76. http://dx.doi.org/10.1017/s0074180900194367.

Full text

Abstract:

To describe pulsar spin-down, a simple combined torque model, that takes into account both the standard magnetic dipole radiation and the electromagnetic radiation from the 3P2 superfluid vortex neutrons inside neutron star, is presented. Using an ordinary exponential model for the magnetic field decay, we investigate pulsar evolution tracks on the diagram, which is quite different from that of the standard magnetic dipole radiation model, especially when the superfluid torque or field decay become dominate.

APA, Harvard, Vancouver, ISO, and other styles

27

Guo, L. F., Q. H. Chen, and P. Li. "Stripe phases in a frustrated spin-1/2 dimer Heisenberg model." International Journal of Modern Physics B 28, no. 22 (July 3, 2014): 1450143. http://dx.doi.org/10.1142/s0217979214501434.

Full text

Abstract:

We use a bond-operator mean-field theory and a generalized spin-wave theory to study the frustrated spin-1/2 dimer Heisenberg model on a square lattice with frustrations in both cardinal and corner directions. We establish the ground state phase diagram with very rich phases. It has been disclosed that the frustrations in cardinal directions can induce exotic superfluid (SF) and supersolid (SS) phases. By introducing the frustrations in corner directions, we found more interesting phases, such as the striped superfluid (S-SF) and the striped supersolid (S-SS). We also investigate the excitation spectra and analyze the anisotropic spin-wave velocities of the stripe phases.

APA, Harvard, Vancouver, ISO, and other styles

28

Peng, Q. H., L. D. Zhang, X. L. Luo, and C. K. Chou. "A Rocket Model of Neutrino Jet for Pulsar Kicks." Symposium - International Astronomical Union 218 (2004): 33–36. http://dx.doi.org/10.1017/s0074180900180507.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

ANDERSSON, N., and G. L. COMER. "ENTROPY ENTRAINMENT AND DISSIPATION IN FINITE TEMPERATURE SUPERFLUIDS." International Journal of Modern Physics D 20, no. 07 (July 15, 2011): 1215–33. http://dx.doi.org/10.1142/s0218271811019396.

Full text

Abstract:

Neutron stars are expected to contain several distinct superfluid components, ranging from the neutron superfluid which coexists with the elastic crust to the mixed neutron superfluid/proton superconductor in the outer core and more exotic phases like superfluid hyperons and colour-flavour-locked superconducting quarks in the deep core. These different phases may have significant effect on the dynamics of the system. Building on a general variational framework for multifluid dynamics, we consider the behaviour of superfluid systems at finite temperatures (as required to understand various dissipation channels). As a demonstration of the validity of the underlying principles, such as treating the excitations in the system as a massless "entropy" fluid, we show that the model is formally equivalent to the traditional two-fluid approach for superfluid helium. In particular, we demonstrate how the entropy entrainment is related to the "normal fluid density". We also show how the superfluid constraint of irrotationality reduces the number of dissipation coefficients in the system. The analysis provides insight into the more general problem where vortices are present in the superfluid, and we discuss how the so-called mutual friction force can be accounted for. The end product is a formalism for finite temperature effects in a single condensate that can be applied to both low temperature laboratory systems and the various superfluid phases in a neutron star. This provides a key step towards the modelling of more realistic neutron star dynamics, and the understanding of a range of phenomena from pulsar glitches to magnetar seismology and the gravitational-wave-driven r-mode instability.

APA, Harvard, Vancouver, ISO, and other styles

30

CHAPLINE, GEORGE. "QUANTUM MODEL FOR SPACE-TIME." Modern Physics Letters A 07, no. 22 (July 20, 1992): 1959–65. http://dx.doi.org/10.1142/s0217732392001671.

Full text

Abstract:

It is suggested that a recently constructed condensate wave function for a three-dimensional anyonic superfluid can be reinterpreted as a coherent state for gravitons. This wave function provides for the first time a mathematical model showing how macroscopic space-time might emerge from microscopic fluctuations in topology, and suggests that the observable universe may be in a nearly pure quantum state.

APA, Harvard, Vancouver, ISO, and other styles

31

HUANG, KERSON. "DARK ENERGY AND DARK MATTER IN A SUPERFLUID UNIVERSE." International Journal of Modern Physics A 28, no. 28 (November 10, 2013): 1330049. http://dx.doi.org/10.1142/s0217751x13300494.

Full text

Abstract:

The vacuum is filled with complex scalar fields, such as the Higgs field. These fields serve as order parameters for superfluidity (quantum phase coherence over macroscopic distances), making the entire universe a superfluid. We review a mathematical model consisting of two aspects: (a) emergence of the superfluid during the big bang; (b) observable manifestations of superfluidity in the present universe. The creation aspect requires a self-interacting scalar field that is asymptotically free, i.e. the interaction must grow from zero during the big bang, and this singles out the Halpern–Huang potential, which has exponential behavior for large fields. It leads to an equivalent cosmological constant that decays like a power law, and this gives dark energy without "fine-tuning." Quantum turbulence (chaotic vorticity) in the early universe was able to create all the matter in the universe, fulfilling the inflation scenario. In the present universe, the superfluid can be phenomenologically described by a nonlinear Klein–Gordon equation. It predicts halos around galaxies with higher superfluid density, which is perceived as dark matter through gravitational lensing. In short, dark energy is the energy density of the cosmic superfluid, and dark matter arises from local fluctuations of the superfluid density.

APA, Harvard, Vancouver, ISO, and other styles

32

Hodson, Alistair O., Hongsheng Zhao, Justin Khoury, and Benoit Famaey. "Galaxy clusters in the context of superfluid dark matter." Astronomy & Astrophysics 607 (November 2017): A108. http://dx.doi.org/10.1051/0004-6361/201630069.

Full text

Abstract:

Context. The mass discrepancy in the Universe has not been solved by the cold dark matter (CDM) or the modified Newtonian dynamics (MOND) paradigms so far. The problems and solutions of either scenario are mutually exclusive on large and small scales. It has recently been proposed, by assuming that dark matter is a superfluid, that MOND-like effects can be achieved on small scales whilst preserving the success of ΛCDM on large scales. Detailed models within this “superfluid dark matter” (SfDM) paradigm are yet to be constructed. Aims. Here, we aim to provide the first set of spherical models of galaxy clusters in the context of SfDM. We aim to determine whether the superfluid formulation is indeed sufficient to explain the mass discrepancy in galaxy clusters. Methods. The SfDM model is defined by two parameters. Λ can be thought of as a mass scale in the Lagrangian of the scalar field that effectively describes the phonons, and it acts as a coupling constant between the phonons and baryons. m is the mass of the DM particles. Based on these parameters, we outline the theoretical structure of the superfluid core and the surrounding “normal-phase” dark halo of quasi-particles. The latter are thought to encompass the largest part of galaxy clusters. Here, we set the SfDM transition at the radius where the density and pressure of the superfluid and normal phase coincide, neglecting the effect of phonons in the superfluid core. We then apply the formalism to a sample of galaxy clusters, and directly compare the SfDM predicted mass profiles to data. Results. We find that the superfluid formulation can reproduce the X-ray dynamical mass profile of clusters reasonably well, but with a slight under-prediction of the gravity in the central regions. This might be partly related to our neglecting of the effect of phonons in these regions. Two normal-phase halo profiles are tested, and it is found that clusters are better defined by a normal-phase halo resembling an Navarro-Frenk-White-like structure than an isothermal profile. Conclusions. In this first exploratory work on the topic, we conclude that depending on the amount of baryons present in the central galaxy and on the actual effect of phonons in the inner regions, this superfluid formulation could be successful in describing galaxy clusters. In the future, our model could be made more realistic by exploring non-sphericity and a more realistic SfDM to normal phase transition. The main result of this study is an estimate of the order of magnitude of the theory parameters for the superfluid formalism to be reasonably consistent with clusters. These values will have to be compared to the true values needed in galaxies.

APA, Harvard, Vancouver, ISO, and other styles

33

Aitken, Frédéric, Ferdinand Volino, Luis Guillermo Mendoza-Luna, Klaus von Haeften, and Jussi Eloranta. "A thermodynamic model to predict electron mobility in superfluid helium." Physical Chemistry Chemical Physics 19, no. 24 (2017): 15821–32. http://dx.doi.org/10.1039/c7cp03067c.

Full text

Abstract:

Electron mobility in superfluid helium is modeled between 0.1 and 2.2 K by a van der Waals-type thermodynamic equation of state, which relates the free volume of solvated electrons to temperature, density, and phase dependent internal pressure.

APA, Harvard, Vancouver, ISO, and other styles

34

Palkanoglou, Georgios, and Alexandros Gezerlis. "Superfluid Neutron Matter with a Twist." Universe 7, no. 2 (January 26, 2021): 24. http://dx.doi.org/10.3390/universe7020024.

Full text

Abstract:

Superfluid neutron matter is a key ingredient in the composition of neutron stars. The physics of the inner crust are largely dependent on those of its S-wave neutron superfluid, which has made its presence known through pulsar glitches and modifications in neutron star cooling. Moreover, with recent gravitational-wave observations of neutron star mergers, the need for an equation of state for the matter of these compact stars is further accentuated and a model-independent treatment of neutron superfluidity is important. Ab initio techniques developed for finite systems can be guided to perform extrapolations to the thermodynamic limit and attain this model-independent extraction of various quantities of infinite superfluid neutron matter. To inform such an extrapolation scheme, we performed calculations of the neutron 1S0 pairing gap using model-independent odd–even staggering in the context of the particle-conserving, projected Bardeen–Cooper–Schrieffer (BCS) theory under twisted boundary conditions. While the practice of twisted boundary conditions is standard in solid-state physics and has been used repeatedly in the past to reduce finite-size effects, this is the first time that it has been employed in the context of pairing. We find that a twist-averaging approach results in a substantial reduction of the finite-size effects, bringing systems with N⪆50 within a 2% error margin from the infinite system. This can significantly reduce extrapolation-related errors in the extraction of superfluid neutron matter quantities.

APA, Harvard, Vancouver, ISO, and other styles

35

Barybin, Anatoly A. "Nonstationary Superconductivity: Quantum Dissipation and Time-Dependent Ginzburg-Landau Equation." Advances in Condensed Matter Physics 2011 (2011): 1–10. http://dx.doi.org/10.1155/2011/425328.

Full text

Abstract:

Transport equations of the macroscopic superfluid dynamics are revised on the basis of a combination of the conventional (stationary) Ginzburg-Landau equation and Schrödinger's equation for the macroscopic wave function (often called the order parameter) by using the well-known Madelung-Feynman approach to representation of the quantum-mechanical equations in hydrodynamic form. Such an approach has given (a) three different contributions to the resulting chemical potential for the superfluid component, (b) a general hydrodynamic equation of superfluid motion, (c) the continuity equation for superfluid flow with a relaxation term involving the phenomenological parameters and , (d) a new version of the time-dependent Ginzburg-Landau equation for the modulus of the order parameter which takes into account dissipation effects and reflects the charge conservation property for the superfluid component. The conventional Ginzburg-Landau equation also follows from our continuity equation as a particular case of stationarity. All the results obtained are mutually consistent within the scope of the chosen phenomenological description and, being model-neutral, applicable to both the low- and high- superconductors.

APA, Harvard, Vancouver, ISO, and other styles

36

Snyder, H. A. "Dewar to dewar model for superfluid helium transfer." Cryogenics 28, no. 2 (February 1988): 86–89. http://dx.doi.org/10.1016/0011-2275(88)90051-3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Sciacca, Michele, David Jou, and Maria Stella Mongiovì. "K-ϵ-L model in turbulent superfluid helium." Physica A: Statistical Mechanics and its Applications 548 (June 2020): 123885. http://dx.doi.org/10.1016/j.physa.2019.123885.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Popov, V. A. "Statefinder analysis of the superfluid Chaplygin gas model." Journal of Cosmology and Astroparticle Physics 2011, no. 10 (October 10, 2011): 009. http://dx.doi.org/10.1088/1475-7516/2011/10/009.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Josserand, C., Y. Pomeau, and S. Rica. "Cavitation versus Vortex Nucleation in a Superfluid Model." Physical Review Letters 75, no. 17 (October 23, 1995): 3150–53. http://dx.doi.org/10.1103/physrevlett.75.3150.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Andersson, N., C. Krüger, G. L. Comer, and L. Samuelsson. "A minimal model for finite temperature superfluid dynamics." Classical and Quantum Gravity 30, no. 23 (October 30, 2013): 235025. http://dx.doi.org/10.1088/0264-9381/30/23/235025.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

POMEAU, Y. "DEFECTS AND WAVES IN A MODEL OF SUPERFLUID." International Journal of Bifurcation and Chaos 04, no. 05 (October 1994): 1165–72. http://dx.doi.org/10.1142/s0218127494000861.

Full text

Abstract:

Among physical systems whose physical properties depend on singularities and display some kind of pattern, superfluids play a quite interesting role, because of their quantum nature: in addition to the usual translation and rotation invariance, their invariance in a global phase change has no classical counterpart. This has rather subtle consequences that will be explored, particularly in reference to the problem of limit speed and to the phenomenology linked to the roton spectrum. Using concepts borrowed from pattern formation theory, one may understand the limit speed as the onset of a kind of Eckhaus instability leading to the formation of topo logical defects. Similarly, the emission of rotons may be viewed as resulting from an instability quite similar to a local Rayleigh-Bénard instability.

APA, Harvard, Vancouver, ISO, and other styles

42

Chorin, Alexandre Joel. "A vortex model with superfluid and turbulent percolation." Journal of Statistical Physics 69, no. 1-2 (October 1992): 67–78. http://dx.doi.org/10.1007/bf01053783.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Yeung, Cheung-Hei, Lap-Ming Lin, Nils Andersson, and Greg Comer. "The I-Love-Q Relations for Superfluid Neutron Stars." Universe 7, no. 4 (April 20, 2021): 111. http://dx.doi.org/10.3390/universe7040111.

Full text

Abstract:

The I-Love-Q relations are approximate equation-of-state independent relations that connect the moment of inertia, the spin-induced quadrupole moment, and the tidal deformability of neutron stars. In this paper, we study the I-Love-Q relations for superfluid neutron stars for a general relativistic two-fluid model: one fluid being the neutron superfluid and the other a conglomerate of all charged components. We study to what extent the two-fluid dynamics might affect the robustness of the I-Love-Q relations by using a simple two-component polytropic model and a relativistic mean field model with entrainment for the equation-of-state. Our results depend crucially on the spin ratio Ωn/Ωp between the angular velocities of the neutron superfluid and the normal component. We find that the I-Love-Q relations can still be satisfied to high accuracy for superfluid neutron stars as long as the two fluids are nearly co-rotating Ωn/Ωp≈1. However, the deviations from the I-Love-Q relations increase as the spin ratio deviates from unity. In particular, the deviation of the Q-Love relation can be as large as O(10%) if Ωn/Ωp differ from unity by a few tens of percent. As Ωn/Ωp≈1 is expected for realistic neutron stars, our results suggest that the two-fluid dynamics should not affect the accuracy of any gravitational waveform models for neutron star binaries that employ the relation to connect the spin-induced quadrupole moment and the tidal deformability.

APA, Harvard, Vancouver, ISO, and other styles

44

Nguyen, Phong H., and Massimo Boninsegni. "Superfluid Transition and Specific Heat of the 2D x-y Model: Monte Carlo Simulation." Applied Sciences 11, no. 11 (May 27, 2021): 4931. http://dx.doi.org/10.3390/app11114931.

Full text

Abstract:

We present results of large-scale Monte Carlo simulations of the 2D classical x-y model on the square lattice. We obtain high accuracy results for the superfluid fraction and for the specific heat as a function of temperature, for systems of size L×L with L up to 212. Our estimate for the superfluid transition temperature is consistent with those furnished in all previous studies. The specific heat displays a well-defined peak, whose shape and position are independent of the size of the lattice for L>28, within the statistical uncertainties of our calculations. The implications of these results on the interpretation of experiments on adsorbed thin films of 4He are discussed.

APA, Harvard, Vancouver, ISO, and other styles

45

Owerre, Solomon A. "Spin wave theory of spin-1/2 XY model with ring exchange on a triangular lattice." Canadian Journal of Physics 91, no. 7 (July 2013): 542–47. http://dx.doi.org/10.1139/cjp-2012-0462.

Full text

Abstract:

We present the linear spin wave theory calculation of the superfluid phase of a hard-core boson J-K model with nearest neighbour exchange J and four-particle ring-exchange K at half filling on the triangular lattice, as well as the phase diagrams of the system at zero and finite temperatures. A similar analysis has been done on a square lattice (Schaffer et al. Phys. Rev. B, 80, 014503 (2009)). We find similar behaviour to that of a square lattice but with different spin wave values of the thermodynamic quantities. We also find that the pure J model (XY model), which has a well-known uniform superfluid phase with an ordered parameter [Formula: see text] at zero temperature is quickly destroyed by the inclusion of negative-K ring-exchange interactions, favouring a state with a (4π/3, 0) ordering wavevector. We further study the behaviour of the finite-temperature Kosterlitz–Thouless phase transition (TKT) in the uniform superfluid phase, by forcing the universal quantum jump condition on the finite-temperature spin wave superfluid density. We find that for K < 0, the phase boundary monotonically decreases to T = 0 at K/J = −4/3, where a phase transition is expected and TKT decreases rapidly, while for positive K, TKT reaches a maximum at some K ≠ 0. It has been shown on a square lattice using quantum Monte Carlo (QMC) simulations that for small K > 0 away from the XY point, the zero-temperature spin stiffness value of the XY model is decreased (Melko and Sandvik. Ann. Phys. 321, 1651 (2006)). Our result seems to agree with this trend found in QMC simulations for two-dimensional systems.

APA, Harvard, Vancouver, ISO, and other styles

46

Guo, Shuo, Devranjan Samanta, Yi Peng, Xinliang Xu, and Xiang Cheng. "Symmetric shear banding and swarming vortices in bacterial superfluids." Proceedings of the National Academy of Sciences 115, no. 28 (June 25, 2018): 7212–17. http://dx.doi.org/10.1073/pnas.1722505115.

Full text

Abstract:

Bacterial suspensions—a premier example of active fluids—show an unusual response to shear stresses. Instead of increasing the viscosity of the suspending fluid, the emergent collective motions of swimming bacteria can turn a suspension into a superfluid with zero apparent viscosity. Although the existence of active superfluids has been demonstrated in bulk rheological measurements, the microscopic origin and dynamics of such an exotic phase have not been experimentally probed. Here, using high-speed confocal rheometry, we study the dynamics of concentrated bacterial suspensions under simple planar shear. We find that bacterial superfluids under shear exhibit unusual symmetric shear bands, defying the conventional wisdom on shear banding of complex fluids, where the formation of steady shear bands necessarily breaks the symmetry of unsheared samples. We propose a simple hydrodynamic model based on the local stress balance and the ergodic sampling of nonequilibrium shear configurations, which quantitatively describes the observed symmetric shear-banding structure. The model also successfully predicts various interesting features of swarming vortices in stationary bacterial suspensions. Our study provides insights into the physical properties of collective swarming in active fluids and illustrates their profound influences on transport processes.

APA, Harvard, Vancouver, ISO, and other styles

47

Sourie, Aurélien, and Nicolas Chamel. "Generalization of the Kutta–Joukowski theorem for the hydrodynamic forces acting on a quantized vortex." International Journal of Modern Physics B 34, no. 10 (April 20, 2020): 2050099. http://dx.doi.org/10.1142/s021797922050099x.

Full text

Abstract:

The hydrodynamic forces acting on a quantized vortex in a superfluid have long been a highly controversial issue. A new approach, originally developed in the astrophysical context of compact stars, is presented to determine these forces by considering small perturbations of the asymptotically uniform flows in the region far from the vortex in the framework of Landau–Khalatnikov two-fluid model. Focusing on the irrotational part of the flows in the Helmholtz decomposition, the classical Kutta–Joukowski theorem from ordinary hydrodynamics is thus generalized to superfluid systems. The same method is applied to predict the hydrodynamic forces acting on vortices in cold atomic condensates and superfluid mixtures.

APA, Harvard, Vancouver, ISO, and other styles

48

Montoli, A., M. Antonelli, and P. M. Pizzochero. "The role of mass, equation of state, and superfluid reservoir in large pulsar glitches." Monthly Notices of the Royal Astronomical Society 492, no. 4 (January 20, 2020): 4837–46. http://dx.doi.org/10.1093/mnras/staa149.

Full text

Abstract:

ABSTRACT Observations of pulsar glitches may provide insights on the internal physics of neutron stars and recent studies show how it is in principle possible to constrain pulsar masses with timing observations. The reliability of these estimates depends on the current uncertainties about the structure of neutron stars and on our ability to model the dynamics of the superfluid neutrons in the internal layers. We assume a simplified model for the rotational dynamics of a neutron star and estimate an upper bound to the mass of 25 pulsars from their largest glitch and average activity: the aim is to understand to which extent the mass constraints are sensitive to the choice of the unknown structural properties of neutron stars, like the extension of the superfluid region and the equation of state. Reasonable values, within the range measured for neutron star masses, are obtained only if the superfluid domain extends for at least a small region inside the outer core, which is compatible with calculations of the neutron S-wave pairing gap. Moreover, the mass constraints stabilize when the superfluid domain extends to densities over nuclear saturation, irrespective of the equation of state tested.

APA, Harvard, Vancouver, ISO, and other styles

49

Inoue, Hitoshi. "Superfluid-Mott insulator and superfluid-charge density wave transitions in a one-dimensional Bose–Hubbard model." Physica B: Condensed Matter 443 (June 2014): 120–24. http://dx.doi.org/10.1016/j.physb.2014.02.050.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

KOGA, AKIHISA, and PHILIPP WERNER. "PSEUDOGAP BEHAVIOR IN THE INFINITE DIMENSIONAL ATTRACTIVE HUBBARD MODEL." Modern Physics Letters B 25, no. 12n13 (May 30, 2011): 973–78. http://dx.doi.org/10.1142/s0217984911026681.

Full text

Abstract:

We study the attractive Hubbard model in infinite spatial dimensions by means of dynamical mean-field theory with continuous-time quantum Monte Carlo simulations. Calculating the pair potential and the spectral function, we discuss the stability of the superfluid state at low temperatures. The pseudogap behavior above the critical temperature is also addressed.

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!