Eddy core transition and covalent binding of eddy molecules

[Submitted on 15 Sep 2022]

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Overview: Neutron $^3P_2$ superfluidity, consisting of neutron pairs with total angular momentum $J=2$ accompanied by spin triplets and $P$ waves, is believed to be realized in neutron star cores. Within Ginzburg-Landau theory, a singly-quantized vortex is split into two semi-quantized non-abelian vortices connected by one (or three) solitons, yielding vortex molecules with soliton coupling. was previously discovered to form Absence (presence) of magnetic fields parallel to them. In this paper, we investigate the proximity effect of two vortex molecules by exhausting all possible two vortex molecule states consisting of four half-quantized eddies and determining the phase diagrams spanned by magnetic field and rotational velocity. As the rotation speed increases, the distance between the two vortex molecules decreases. It can be seen that in magnetic fields below the critical value, as the rotation speed increases, the two separated vortex molecules transition to dimerized vortex molecules, where the two vortex molecules are bridged by two solitons. . This is called a “covalent bond” by analogy. with chemical molecules. We also find that the order of the constituent half-quantized vortex cores transitions from ferromagnetic to circular order as the vortex molecules approach. On the other hand, dimerization does not occur in magnetic fields above the critical value. Instead, we find that the polarization direction of the vortex molecules transitions from a configuration parallel to the separation as it approaches a configuration perpendicular to the separation. We also give some examples of three and four vortex molecular states.