Conditional recovery of time-reversal symmetry in many nucleus systems

Abstract

The propagation of non-topological solitons in many-nucleus systems is studied based on timedependent density functional calculations, focusing on mass and energy dependence. The dispersive property and the nonlinearity of the system, which are inherently included in the nuclear density functional, are essential factors to form a non-topological soliton. On the other hand, soliton propagation is prevented by charge equilibration, and competition can appear between soliton formation and disruption. In this article, based on the energy-dependence of the two competitive factors, the concept of conditional recovery of time-reversal symmetry is proposed in many-nucleus systems. It clarifies the possibility of preserving the nuclear medium inside natural or artificial nuclear reactors, at a suitable temperature. From an astrophysical point of view, the existence of the lowtemperature solitonic core of compact stars is suggested.

Solitons in Nuclear Time-Dependent Density Functional Theory

“…The SV-bas parameter set is known well for reproducing the neutron skin thickness of heavy nuclei such as 208 Pb (for a compilation of experimental and theoretical results, see von Neumann-Cosel [31]). The quality of SV-bas in some relevant heavy nuclei can be found in Iwata and Stevenson [7]. On the other hand, the description of light ions (helium isotopes) using SV-bas is also confirmed to be sufficiently good [32].…”

“…Before moving on to the main discussion, we briefly review the preceding results [7,32] [7]). For those lighter cases, a rough sketch of the energy-dependence is as follows: the soliton property is not so active for low energies less than a few MeV per nucleon; soliton property becomes active around 10 MeV per nucleon, it achieves almost the perfect transparency around 10-30 MeV per nucleon, and the transparency again decreases for much higher energies (Figures 2, 3 of Iwata and Stevenson [7]). For a mass dependence, the most decisive factor for the soliton propagation in heavier collisions has been clarified to be the appearance of the fragmentation including the nucleon emissions (mostly neutron emission).…”

“…For an astrophysical comparison it is practical to define the typical temperature of collision using the kinetic energy per nucleon or the relative velocity of the collision. Based on the Bethe formula [42], the temperature of nuclear collision [7,43] is defined by…”

“…Furthermore, perfect fluidity is associated with the dissipation property of low-energy heavy-ion collisions that has been a long standing open problem in microscopic nuclear reaction theory. Perfect fluidity is also associated with the conservation of nuclear matter without the loss of any information: i.e., isentropic property arising from the time-reversal symmetry [7]. As the conservation property of the soliton has already been utilized in the optical fiber, the preservation property of nuclear matter is expected to be utilized in the nuclear engineering for preserving and condensing a certain projectile nucleus.…”

Molecular dynamics investigation of soliton propagation in a two‐dimensional Yukawa liquid

“…Despite its apparent simplicity it is very rich and has a large variety of solutions, including spatially localized solitary waves and periodic cnoidal waves. In the meantime, solitons have been identified in many different fields beyond hydrodynamics, including optics (optical fibers and non-liner media) [4], magnetism [5], nuclear physics [6], and Bose-Einstein condensates [7].…”