Dipolar Electromagetic Condensate

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[Submitted on 9 Aug 2024]

On the Origin of Magnetar Fields: Chiral Magnetic Instability in Neutron Star Crusts​

Clara Dehman, José A. Pons
We investigate the chiral magnetic instability in the crust of a neutron star as a potential mechanism for amplifying magnetic fields. This instability may become active when small deviations from chemical equilibrium are sustained over decades, driven by the star's gradual spin-down or residual heat loss. Our findings suggest that this mechanism can produce strong, large-scale magnetic fields consistent with models that align with observational data. Additionally, this instability naturally generates magnetic helicity in the star's crust, which is crucial for forming and maintaining strong dipolar toroidal fields, often invoked to explain magnetar observational phenomena. Our results offer a microphysically-based alternative to classical hydrodynamical dynamos for the origin of magnetar magnetic fields, addressing a long-standing debate in the field.
 
[Submitted on 16 Aug 2024]

Reality of Inverse Cascading in Neutron Star Crusts​

Clara Dehman, Axel Brandenburg
The braking torque that dictates the timing properties of magnetars is closely tied to the large-scale dipolar magnetic field on their surface. The formation of this field has been a topic of ongoing debate. One proposed mechanism, based on macroscopic principles, involves an inverse cascade within the neutron star's crust. However, this phenomenon has not been observed in realistic simulations. In this study, we provide compelling evidence supporting the feasibility of the inverse cascading process in the presence of an initial helical magnetic field within realistic neutron star crusts and discuss its contribution to the amplification of the large-scale magnetic field. Our findings, derived from a systematic investigation that considers various coordinate systems, peak wavenumber positions, crustal thicknesses, magnetic boundary conditions, and magnetic Lundquist numbers, reveal that the specific geometry of the crustal domain - with its extreme aspect ratio - requires an initial peak wavenumber from small-scale structures for the inverse cascade to occur. However, this extreme aspect ratio limits the inverse cascade to magnetic field structures on scales comparable to the neutron star's crust, making the formation of a large-scale dipolar surface field unlikely. Despite this limitation, the inverse cascade can significantly impact the magnetic field evolution in the interior of the crust, potentially explaining the observed characteristics of highly magnetized objects with weak surface dipolar fields, such as low-field magnetars or central compact objects.
 
To understand dipolar jets, scientists are experimenting to find ways of creating and controlling them, which may lead to the ultimate fuel in space travel.
Dipolar jets are found at the center of the Milkyway.
M87 the dipolar jet goes for 100,000 light years.


[Submitted on 19 Aug 2024 (v1), last revised 28 Aug 2024 (this version, v2)]

Topological phase transitions in perovskite superlattices driven by temperature, electric field, and doping​

Jiyuan Yang, Shi Liu
Many dipolar topological structures have been experimentally demonstrated in (PbTiO3)n/(SrTiO3)n superlattices, such as flux-closure, vortice, and skyrmion
 
Porphyrion"s Giat Jet Blasts are not created by infall pressure.

Yes, stars and galaxies are pulled to the core and broken down to quantum matter forming part of a giant Condensate that creates stable dipolar moments. The vector fields form a stable jet lasting over 23 million years. The matter comes from the core and not from the external turbulence as noted in the Youtube report.

Well that is my opinion.
 
The Dipolar Electro-magnetic jets are a common property of all Transient Condensates. Transient phases from Atomic to Neutron to quark, partonic to Axion, etc. The greater the compaction the greater the jets formed.


[Submitted on 3 May 2024 (v1), last revised 24 Aug 2024 (this version, v2)]

Jetlike structures in low-mass binary neutron star merger remnants​

Jamie Bamber, Antonios Tsokaros, Milton Ruiz, Stuart L. Shapiro
GW170817 and GRB 170817A provided direct evidence that binary neutron star (NSNS) mergers can produce short gamma-ray bursts (sGRBs). However, questions remain about the nature of the central engine. Depending on the mass, the remnant from a NSNS merger may promptly collapse to a black hole (BH), form a hypermassive neutron star (HMNS) which undergoes a delayed collapse to a BH, a supramassive neutron star (SMNS) with a much longer lifetime, or an indefinitely stable NS. There is strong evidence that a BH with an accretion disk can launch a sGRB-compatible jet via the Blandford-Znajek mechanism, but whether a supramassive star can do the same is less clear. We have performed general relativistic magnetohydrodynamics simulations of the merger of both irrotational and spinning, equal-mass NSNSs constructed from a piecewise polytropic representation of the SLy equation of state, with a range of gravitational masses that yield remnants with mass above and below the supramassive limit. Each NS is endowed with a dipolar magnetic field extending from the interior into the exterior, as in a radio pulsar. We examine cases with different initial binary masses, including a case which produces a HMNS which collapses to a BH, and lower mass binaries that produce SMNS remnants. We find similar jetlike structures for both the SMNS and HMNS remnants that meet our basic critera for an incipient jet. The outflow for the HMNS case is consistent with a Blandford-Znajek (BZ) jet. There is sufficient evidence that such BZ-powered outflows can break out and produce ulrarelativistic jets so that we can describe the HMNS system as a sGRB progenitor. However, the incipient jets from the SMNS remnants have much more baryon pollution and we see indications of inefficient acceleration and mixing with the surrounding debris. Therefore, we cannot conclude that SMNS outflows are the progenitors of sGRBs.
 
Exciting times in understanding dipolar magnetic fields and how dipolar jets can be formed.

[Submitted on 4 Sep 2024]

Superfluidity of dipolar excitons in a double layer of α−T3 with a mass term​

Oleg L. Berman, Godfrey Gumbs, Gabriel P. Martins, Paula Fekete
We predict Bose-Einstein condensation and superfluidity of dipolar excitons, formed by electron-hole pairs in spatially separated gapped hexagonal α−T3 (GHAT3) layers. In the α−T3 model, the AB-honeycomb lattice structure is supplemented with C atoms located at the centers of the hexagons in the lattice. We considered the α−T3 model in the presence of a mass term which opens a gap in the energy dispersive spectrum. The gap opening mass term, caused by a weak magnetic field, plays the role of Zeeman splitting at low magnetic fields for this pseudospin-1 system. The band structure of GHAT3 monolayers leads to the formation of two distinct types of excitons in the GHAT3 double layer. We consider two types of dipolar excitons in double-layer GHAT3: (a) ``A excitons'', which are bound states of electrons in the conduction band (CB) and holes in the intermediate band (IB) and (b) ``B excitons'', which are bound states of electrons in the CB and holes in the valence band (VB). The binding energy of A and B dipolar excitons is calculated. For a two-component weakly interacting Bose gas of dipolar excitons in a GHAT3 double layer, we obtain the energy dispersion of collective excitations, the sound velocity, the superfluid density, and the mean-field critical temperature Tc for superfluidity.
 
Dipolar field research is important to understand how condensates function.

[Submitted on 4 Nov 2024]

Reflections on dipolar quantum fluids​

Wilhelm Zwerger
We present a thermodynamic description of ultracold gases with dipolar interactions which properly accounts for the long-range nature and broken rotation invariance of the interactions. It involves an additional thermodynamic field conjugate to the linear extension of the gas along the direction of the dipoles. The associated uniaxial pressure shows up as a deviation from the Gibbs-Duhem relation in the density profile of a trapped gas. It has to vanish in self-bound droplets, a condition which determines the observed dependence of the aspect ratio on particle number. A tensorial generalization of the virial theorem and a number of further exact thermodynamic relations are derived. Finally, extending a model due to Nozières, a simple criterion for the freezing transition to a superfluid mass density wave is given.
 

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