Neutrino emissivity of anisotropic neutron superfluids

Leinson, L. B.

doi:10.1103/physrevc.87.025501

Cited by 26 publications

(19 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The nematic phase has a continuous degeneracy 29 which is solved by either magnetic field or 6th order terms in the GL free energy, and the uniaxial nematic (UN) phase is favored at zero temperature while D 2 -biaxial nematic (BN) and D 4 -BN phases are favored for finite and strong magnetic fields, respectively 30 , relevant for magnetars. Low-energy excitations in 3 P 2 superfluids affect the cooling process by neutrino emission [31][32][33][34][35][36][37][38][39][40][41][42] . The rapid cooling due to 3 P 2 superfluids was studied for Cassiopeia A [43][44][45] , but a direct proof of the existence of the 3 P 2 superfluidity is yet elusive.…”

Section: Introductionmentioning

confidence: 99%

Microscopic description of axisymmetric vortices in P23 superfluids

Yumoto

Mizushima

Nitta

2020

Phys. Rev. Research

View full text Add to dashboard Cite

We study quantized vortices in 3 P 2 superfluids using a microscopic theory for the first time. The theory is based on the Eilenberger equation to determine the order parameters and the Bogoliubov-de Gennes (BdG) equation to obtain the eigenenergies and the core magnetization. Within axisymmetric vortex configurations, we find several stable and metastable vortex configurations which depend on the strength of a magnetic field, similar to a v-vortex and o-vortex in 3 He superfluids. We demonstrate that the o-vortex is the most stable axisymmetric vortex in the presence of a strong magnetic field, and find two zero-energy Majorana fermion bound states in the o-vortex core. We show that the profiles of the core magnetization calculated using the BdG equation are drastically different from those calculated using only the order parameter profiles known before.

show abstract

Section: Introductionmentioning

confidence: 99%

Microscopic description of axisymmetric vortices in P23 superfluids

Yumoto

Mizushima

Nitta

2020

Phys. Rev. Research

View full text Add to dashboard Cite

show abstract

“…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].…”

mentioning

confidence: 99%

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

2019

View full text Add to dashboard Cite

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...

show abstract

“…Nematic phases preserve the time reversal symmetry (TRS), while the cyclic and ferromagnetic phases are non-unitary states with spontaneously broken TRS. The richness of 3 P 2 order parameters brings about various types of massive/massless bosonic modes [40][41][42][43][44][45][46][47][48] and exotic topological defects, including spontaneously magnetized vortices, fractional, and non-abelian vortices [36,[49][50][51][52]. In contrast to "bosonic" excitations, there have been no studies on the topology of "fermions" in 3 P 2 superfluids.…”

mentioning

confidence: 99%

P23superfluids are topological

2017

View full text Add to dashboard Cite

We clarify topology of 3 P2 superfluids which are expected to be realized in the inner cores of neutron stars and cubic odd-parity superconductors.3 P2 phases include uniaxial/biaxial nematic phases and nonunitary ferromagnetic and cyclic phases. We here show that all the phases are accompanied by different types of topologically protected gapless fermions: Surface Majorana fermions in nematic phases and a quartet of (single) itinerant Majorana fermions in the cyclic (ferromagnetic) phase. Using the superfluid Fermi liquid theory, we also demonstrate that dihedral-two and -four biaxial nematic phases are thermodynamically favored in the weak coupling limit under a magnetic field. It is shown that the tricritical point exists on the phase boundary between these two phases and may be realized in the core of realistic magnetars. We unveil the intertwining of symmetry and topology behind mass acquisition of surface Majorana fermions in nematic phases.

show abstract

Neutrino emissivity of anisotropic neutron superfluids

Cited by 26 publications

References 27 publications

Microscopic description of axisymmetric vortices in P23 superfluids

Microscopic description of axisymmetric vortices in P23 superfluids

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

P23superfluids are topological

Contact Info

Product

Resources

About