Pseudoconformal equation of state in compact-star matter from topology change and hidden symmetries of QCD

We construct a new effective field theory approach to the equation of state(EoS), dubbed pseudo-confomal model 'PCM', for nuclear and compact star matter entirely in terms of effective hadron degrees of freedom. The possible transition at n ^(2-4)n0(where n0 is the normal nuclear matter density) from hadron degrees of freedom to strongly-coupled quark degrees of freedom,giving rise to a soft-to-hard changeover in the EoS that can accommodate the massive stars observed, is effectuated by the topology change at n1/2>~ 2n0 from skyrmions to half-skyrmions without involving local order-parameter fields. The mechanism exploits possible emergence of hidden scale and local symmetries of QCD at high density, leading to a precocious 'pseudo-conformal'sound velocity vs2= 1/3(in unit of c = 1) for n>~ 3n0. The resulting prediction signals a drastic departure from standard nuclear many-body theory in the density regime involved in the massive stars. We suggest that the tidal deformability implemented in gravitational waves coming from coalescing neutron stars in LIGO/Virgo-type observations could pin down the location of the topology change density n1/2.

Nuclear axial currents from scale-chiral effective field theory

By incorporating hidden scale symmetry and hidden local symmetry in the nuclear effective field theory,combined with the double soft-pion theorem, we predict that the Gamow-Teller operator coming from the space component of the axial current should remain unaffected by the QCD vacuum change caused by the baryonic density,whereas the first forbidden beta transition operator coming from the time component should be strongly enhanced.While the latter has been confirmed for some time, the former was given support by a powerful recent ab initio quantum Monte Carlo calculation for light nuclei, which also confirmed the old？chiral filter hypothesis.＂ Formulated in terms of the Fermi-liquid fixed point structure of strong-coupled nuclear interactions, we offer an extremely simple resolution to the long-standing puzzle of the＂quenched g A,＂ gAeff ≈1 [1], found in nuclear Gamow-Teller beta transitions, giant Gamow-Teller resonances, and double beta decays.

N-cluster correlations in four-and five-dimensional percolation

We study N-cluster correlation functions in four-and five-dimensional(4D)and 5D)bond percolation by extensive Monte Carlo simulation.We reformulate the transfer Monte Carlo algorithm for percolation[Phys.Reu.E 72,016126(2005)]using the disjoint-set data structure,and simulate a cylindrical geometry Ld^-1×∞,with the linear size up to L=512 for 4D and 128 for 5D.We determine with 1 high precision all possible N-cluster exponents,for N=2 and 3,and the universal amplitude for a logarithmic correlation function.From the symmetric correlator with N=2,we obtain the correlation-length critical exponent as 1/v=1.4610(12)for 4D and 1/v=1.737(2)for 5D,significantly improving over the existing results.Estimates for the other exponents and the universal logarithmic amplitude have not been reported before to our knowledge.Our work demonstrates the validity of logarithmic conformal field theory and adds to the growing knowledge for high-dimensional percolation.