Spin-polarized neutron matter: Critical unpairing and BCS-BEC precursor
TL;DR: In this paper, the critical magnetic field required for complete destruction of $S$-wave pairing in neutron matter was obtained, thereby setting limits on the pairing and superfluidity of neutrons in the crust and outer core of magnetars.
Abstract: We obtain the critical magnetic field required for complete destruction of $S$-wave pairing in neutron matter, thereby setting limits on the pairing and superfluidity of neutrons in the crust and outer core of magnetars. We find that for fields $B\ensuremath{\ge}{10}^{17}$ G the neutron fluid is nonsuperfluid---if weaker spin 1 superfluidity does not intervene---a result with profound consequences for the thermal, rotational, and oscillatory behavior of magnetars. Because the dineutron is not bound in vacuum, cold dilute neutron matter cannot exhibit a proper BCS-BEC crossover. Nevertheless, owing to the strongly resonant behavior of the $nn$ interaction at low densities, neutron matter shows a precursor of the BEC state, as manifested in Cooper-pair correlation lengths being comparable to the interparticle distance. We make a systematic quantitative study of this type of BCS-BEC crossover in the presence of neutron fluid spin polarization induced by an ultrastrong magnetic field. We evaluate the Cooper-pair wave function, quasiparticle occupation numbers, and quasiparticle spectra for densities and temperatures spanning the BCS-BEC crossover region. The phase diagram of spin-polarized neutron matter is constructed and explored at different polarizations.
Citations
More filters
TL;DR: A survey of quantum many-body methods includes techniques that employ Green functions, correlated basis functions, and Monte Carlo sampling of quantum states, with emphasis on the spatially extended matter encountered in neutron stars, supernova envelopes, and nuclear collisions as mentioned in this paper.
Abstract: Nuclear matter and finite nuclei exhibit the property of superfluidity by forming Cooper pairs. We review the microscopic theories and methods that are being employed to understand the basic properties of superfluid nuclear systems, with emphasis on the spatially extended matter encountered in neutron stars, supernova envelopes, and nuclear collisions. Our survey of quantum many-body methods includes techniques that employ Green functions, correlated basis functions, and Monte Carlo sampling of quantum states. With respect to empirical realizations of nucleonic and hadronic superfluids, this review is focused on progress that has been made toward quantitative understanding of their properties at the level of microscopic theories of pairing, with emphasis on the condensates that exist under conditions prevailing in neutron-star interiors. These include singlet S-wave pairing of neutrons in the inner crust, and, in the quantum fluid interior, singlet-S proton pairing and triplet coupled P-F-wave neutron pairing. Additionally, calculations of weak-interaction rates in neutron-star superfluids within the Green function formalism are examined in detail. We close with a discussion of quantum vortex states in nuclear systems and their dynamics in neutron-star superfluid interiors.
96 citations
Cites background from "Spin-polarized neutron matter: Crit..."
...Computation of the critical field [292] indicates that at a temperature T = 0....
[...]
...In particular, one finds [292] that the Cooper-pair wave functions and the function r|Ψ(r)| exhibit oscillalog10 (n/n0) kFn ∆ m ∗/m μn d ξrms [fm−1] [MeV] [MeV] [fm] [fm] −1....
[...]
...…suggests traces of a BEC in neutron-rich systems such as the halo nuclei or neutron matter in compact objects (Abe and Seki, 2009; Isayev, 2008; Kanada-En’yo et al., 2009; Margueron et al., 2007; Matsuo, 2006; Ramanan and Urban, 2013; Salasnich, 2011; Stein et al., 2016; Sun et al., 2010, 2012)....
[...]
...More recently, signatures of the BCSBEC crossover in spin-polarized neutron matter and the emergence of dineutron correlations in the presence of a magnetic field have received attention [292], generalizing the previous studies of this phenomenon in unmagnetized neutron matter [283–288, 290, 291]....
[...]
...Magnetic fields of this magnitude can suppress the pairing of neutrons and protons in the S-wave state [292, 300], but the mechanisms of suppression for charged and neutral condensates are different....
[...]
01 Jan 2018
TL;DR: In this article, the authors focus on applications of the ideas of superconductivity in neutron stars in a broader context, ranging from the microphysics of pairing in nucleonic superfluids to macroscopic manifestations of superfluidity in pulsars.
Abstract: This review focuses on applications of the ideas of superfluidity and superconductivity in neutron stars in a broader context, ranging from the microphysics of pairing in nucleonic superfluids to macroscopic manifestations of superfluidity in pulsars. The exposition of the basics of pairing, vorticity and mutual friction can serve as an introduction to the subject. We also review some topics of recent interest, including the various types of pinning of vortices, glitches, and oscillations in neutron stars containing superfluid phases of baryonic matter.
91 citations
TL;DR: The inner layers of a neutron star consist of a solid nuclear crust, permeated by a neutron ocean in its densest region, possibly on top of a nuclear “pasta” mantle as mentioned in this paper.
Abstract: Formed in the aftermath of gravitational core-collapse supernova explosions, neutron stars are unique cosmic laboratories for probing the properties of matter under extreme conditions that cannot be reproduced in terrestrial laboratories. The interior of a neutron star, endowed with the highest magnetic fields known and with densities spanning about ten orders of magnitude from the surface to the centre, is predicted to exhibit various phases of dense strongly interacting matter, whose physics is reviewed in this chapter. The outer layers of a neutron star consist of a solid nuclear crust, permeated by a neutron ocean in its densest region, possibly on top of a nuclear “pasta” mantle. The properties of these layers and of the homogeneous isospin asymmetric nuclear matter beneath constituting the outer core may still be constrained by terrestrial experiments. The inner core of highly degenerate, strongly interacting matter poses a few puzzles and questions which are reviewed here together with perspectives for their resolution. Consequences of the dense-matter phases for observables such as the neutron-star mass-radius relationship and the prospects to uncover their structure with modern observational programmes are touched upon.
91 citations
TL;DR: A survey of quantum many-body methods including techniques that employ Green functions, correlated basis functions, and Monte Carlo sampling of quantum states is given in this article, with emphasis on the spatially extended matter encountered in neutron stars, supernova envelopes, and nuclear collisions.
Abstract: Nuclear matter and finite nuclei exhibit the property of superfluidity by forming Cooper pairs. We review the microscopic theories and methods that are being employed to understand the basic properties of superfluid nuclear systems, with emphasis on the spatially extended matter encountered in neutron stars, supernova envelopes, and nuclear collisions. Our survey of quantum many-body methods includes techniques that employ Green functions, correlated basis functions, and Monte Carlo sampling of quantum states. With respect to empirical realizations of nucleonic and hadronic superfluids, this review is focused on progress that has been made toward quantitative understanding of their properties at the level of microscopic theories of pairing, with emphasis on the condensates that exist under conditions prevailing in neutron-star interiors. These include singlet $S$-wave pairing of neutrons in the inner crust, and, in the quantum fluid interior, singlet-$S$ proton pairing and triplet coupled $P$-$F$-wave neutron pairing. Additionally, calculations of weak-interaction rates in neutron-star superfluids within the Green function formalism are examined in detail. We close with a discussion of quantum vortex states in nuclear systems and their dynamics in neutron-star superfluid interiors.
75 citations
TL;DR: In this article, the occurrence of superfluidity and superconductivity in neutron stars is reviewed, and a detailed review of the properties of neutron stars with respect to these properties is presented.
Abstract: Neutron stars, the compact stellar remnants of core-collapse supernova explosions, are unique cosmic laboratories for exploring novel phases of matter under extreme conditions. In particular, the occurrence of superfluidity and superconductivity in neutron stars will be briefly reviewed.
66 citations
References
More filters
23,110 citations
Book•
01 Jan 1953
TL;DR: In this paper, the Hartree-Fock Approximation of many-body techniques and the Electron Gas Polarons and Electron-phonon Interaction are discussed.
Abstract: Mathematical Introduction Acoustic Phonons Plasmons, Optical Phonons, and Polarization Waves Magnons Fermion Fields and the Hartree-Fock Approximation Many-body Techniques and the Electron Gas Polarons and the Electron-phonon Interaction Superconductivity Bloch Functions - General Properties Brillouin Zones and Crystal Symmetry Dynamics of Electrons in a Magnetic Field: de Haas-van Alphen Effect and Cyclotron Resonance Magnetoresistance Calculation of Energy Bands and Fermi Surfaces Semiconductor Crystals I: Energy Bands, Cyclotron Resonance, and Impurity States Semiconductor Crystals II: Optical Absorption and Excitons Electrodynamics of Metals Acoustic Attenuation in Metals Theory of Alloys Correlation Functions and Neutron Diffraction by Crystals Recoilless Emission Green's Functions - Application to Solid State Physics Appendix: Perturbation Theory and the Electron Gas Index.
21,954 citations
TL;DR: In this paper, the authors consider a gas of fermions interacting via an attractive potential and calculate the critical temperature for the onset of superconductivity as a function of the coupling strength.
Abstract: We consider a gas of fermions interacting via an attractive potential. We study the ground state of that system and calculate the critical temperature for the onset of superconductivity as a function of the coupling strength. We compare the behavior of continuum and lattice models and show that the evolution from weak to strong coupling superconductivity is smooth.
1,402 citations
TL;DR: In this paper, the Skyrme effective forces were revisited in order to improve their isospin properties away from the β stability line, and these forces were specifically adjusted to reproduce finite nuclei properties.
1,387 citations