Vortex structure of neutron stars with triplet neutron superfluidity

Shahabasyan, K. M.; Shahabasyan, M. K.

doi:10.1007/s10511-011-9193-6

Cited by 12 publications

(8 citation statements)

References 31 publications

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“…[19]. Recent study of 3 P 2 superfluids includes for instance low energy excitations, their low energy theory, neutrino emission [20][21][22][23][24][25][26][27][28][29], their effects on cooling process [30,31] and the entrainment [32].…”

Section: Introductionmentioning

confidence: 99%

Magnetic properties of quantized vortices in neutronP23superfluids in neutron stars

Masuda

Nitta

2016

Phys. Rev. C

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We discuss quantized vortices in neutron 3 P2 superfluids, which are believed to realize in high density neutron matter such as neutron stars. By using the Ginzburg-Landau free energy for 3 P2 superfluids, we determine the ground state in the absence and presence of the external magnetic field, and numerically construct 3 P2 quantized vortices in the absence and presence of the external magnetic field along the vortex axis (poloidal) or angular direction (toroidal). We find in certain situations the spontaneous magnetization of the vortex core, whose typical magnitude is about 10 7−8 Gauss, but the net magnetic field in a neutron star is negligible because of the ratio of the vortex core size ∼ 10fm and the intervortex distance ∼ 10 −6 m in a vortex lattice.

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Section: Introductionmentioning

confidence: 99%

Magnetic properties of quantized vortices in neutronP23superfluids in neutron stars

Masuda

Nitta

2016

Phys. Rev. C

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“…Thus, the 3 P 2 pairing should be realized in neutron matter at high density. It was discussed that the cooling process by neutrino emission can be described by low-energy excitations [45][46][47][48][49][50][51][52][53][54][55][56] and by quantum vortices [57].…”

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confidence: 99%

Phase structure of neutron P23 superfluids in strong magnetic fields in neutron stars

2019

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We discuss the effect of a strong magnetic field on neutron 3 P2 superfluidity. Based on the attraction in the 3 P2 pair of two neutrons, we derive the Ginzburg-Landau equation in the pathintegral formalism by adopting the bosonization technique and leave the next-to-leading order in the expansion of the magnetic field B. We determine the (T, B) phase diagram with temperature T , comprising three phases: the uniaxial nematic (UN) phase for B = 0, D2-biaxial nematic (BN) and D4-BN phases in finite B and strong B such as magnetars, respectively, where D2 and D4 are dihedral groups. We find that, compared with the leading order in the magnetic field known before, the region of the D2-BN phase in the (T, B) plane is extended by the effect of the nextto-leading-order terms of the magnetic field. We also present the thermodynamic properties, such as heat capacities and spin susceptibility, and find that the spin susceptibility exhibits anisotropies in the UN, D2-BN, and D4-BN phases. This information will be useful to understand the internal structures of magnetars. I. INTRODUCTIONNeutron stars are interesting astrophysical objects whose phenomena are induced by combinations of fundamental forces, i.e., strong interaction, weak interaction, electromagnetic interaction and gravitation (see Refs. [1,2] for recent reviews). Studying neutron stars by several different signals can open a new approach to unveil the interiors in neutron stars. It was epoch-making that gravitational waves from neutron star merger were observed directly [3]. One of the most important properties of neutron stars is accompanied by a strong magnetic field. It is known that the magnitude of the magnetic field is around 10 12 G in standard neutron stars, and, in magnetars, it can reach about 10 15 G at the surface and may reach even larger values in the inside (see Refs. [4,5] for reviews on magnetars). As for the origin of the strong magnetic fields, researchers have studied several mechanisms such as spin-dependent interactions between neutrons [6-9], 1 the pion domain wall [11,12], the spin polarization in quark-matter core [13][14][15] and so on. In neutron matter, the influence of the magnetic field on a neutron is provided by a finite magnetic moment, µ n = −(γ n /2)σ with the gyromagnetic ratio of a neutron, γ n = 1.2 × 10 −13 MeV/T (in natural units, = c = 1), and the Pauli matrices for the neutron spin σ. The interaction between the neutron and the magnetic field (B) supplies the energy splitting between the spin-up state and the spin-down state for a neutron, −µ n ·B. For example, the strong magnetic field |B| ∼ 10 15 G in magnetars gives the mass splitting about O(10) keV (notice the unit relation, 1 T = 10 4 G).The dominant ingredient in neutron stars is the neutron matter, and it exists as superfluidity with a small admixture of superconducting protons and normal electrons (see Refs. [16,17] for recent reviews). In relation to the observations of neutron stars, it is considered that the neutron superfluidity affects relaxation time afte...

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“…We show that the domain wall configurations pass thorough different phases, and unbroken symmetries inside the 5 It is discussed that the cooling process is related not only to low-energy excitation modes but also to quantum vortices [84]. 6 At the 4th order, there happens to exist an SO (5) symmetry in the potential term.…”

Section: Introductionmentioning

confidence: 87%

“…We obtain the spatial configurations of the domain walls by solving the Euler-Lagrange (EL) equation from the GL effective potential. With those solutions, we estimate the energy of domain walls, i.e., the surface energy density, for supposing several different configurations and directions.We show that the domain wall configurations pass thorough different phases, and unbroken symmetries inside the 5 It is discussed that the cooling process is related not only to low-energy excitation modes but also to quantum vortices [84]. 6 At the 4th order, there happens to exist an SO(5) symmetry in the potential term.…”

mentioning

confidence: 87%

Domain walls in neutron P23 superfluids in neutron stars

Yasui

Nitta

2020

Phys. Rev. C

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We work out domain walls in neutron 3 P2 superfluids realized in the core of neutron stars. Adopting the Ginzburg-Landau theory as a bosonic low-energy effective theory, we consider configurations of domain walls interpolating ground states, i.e., the uniaxial nematic (UN), D2-biaxial nematic (D2-BN), and D4-biaxial nematic (D4-BN) phases in the presence of zero, small and large magnetic fields, respectively. We solve the Euler-Lagrange equation from the GL free energy density, and calculate surface energy densities of the domain walls. We find that one extra Nambu-Goldstone mode is localized in the vicinity of a domain wall in the UN phase while a U(1) symmetry restores in the vicinity of one type of domain wall in the D2-BN phase and all domain walls in the D4-BN phase.Considering a pile of domain walls in the neutron stars, we find that the most stable configurations are domain walls perpendicular to the magnetic fields piled up in the direction along the magnetic fields in the D2-BN and D4-BN phases. We estimate the energy released from the deconstruction of the domain walls in the edge of a neutron star, and show that it can reach an astrophysical scale such as glitches in neutron stars. I. INTRODUCTIONDomain walls or kinks are solitonic objects separating two discrete vacua or ground states of a system [1-3] and play important roles in various subjects of physics from condensed matter physics [4] to cosmology [5] and supersymmetric field theories [6]. They are often created in phase transitions associated with symmetry breakings [7]. In cosmology, if they appear at a phase transition in the early Universe, then the so-called domain wall problem occurs [5]: the domain wall energy dominates Universe to make it collapse. In helium superfluids, such domain walls are created in a similar manner, thereby simulating cosmological phase transitions [8]. Here, we focus on domain walls in neutron stars, more precisely those in nuclear matter.Neutron stars are compact stars under extreme conditions, thereby serving as astrophysical laboratories for studying nuclear matter at high density, under rapid rotation and with a strong magnetic field (see Refs. [9,10] for recent reviews). The recent progresses in astrophysical observations promote us to study the neutron stars more precisely, such as the recent reports on massive neutron stars whose masses are almost twice as large as the solar mass [11,12] and the gravitational waves from a binary neutron star merger [13].Inside neutron stars, one of the most important key ingredients for understanding the inner structure is neutron superfluidity and proton superconductivity (see for recent reviews). Since the superfluid and superconducting components can alter excitation modes at low energy from the normal phase, their existence can affect several * yasuis@keio.jp † nitta(at)phys-h.keio.ac.jp arXiv:1907.12843v1 [nucl-th] 30 Jul 20191 Although the 1 S 0 superfluidity at low density was proposed in Ref. [28], it was shown in Ref.[29] that this channel turns to be repulsive due...

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Vortex structure of neutron stars with triplet neutron superfluidity

Cited by 12 publications

References 31 publications

Magnetic properties of quantized vortices in neutronP23superfluids in neutron stars

Magnetic properties of quantized vortices in neutronP23superfluids in neutron stars

Phase structure of neutron P23 superfluids in strong magnetic fields in neutron stars

Domain walls in neutron P23 superfluids in neutron stars

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