The properties of pairing correlation in nuclear matter are investigated by using various versions of Skyrme forces. Truncation of states involving pairing correlation, necessary due to zero range nature of the Skyrme force, is discussed in detail. A plateau appears in pairing gap versus cutoff for each force. We propose to choose the cutoff parameter in the middle of the plateau so that the pa...

We introduce a coarse-grained RNA model for molecular dynamics simulations, RACER (RnA CoarsE-gRained). RACER achieves accurate native structure prediction for a number of RNAs (average RMSD of 2.93 Å) and the sequence-specific variation of free energy is in excellent agreement with experimentally measured stabilities (R2 = 0.93). Using RACER, we identified hydrogen-bonding (or base pairing), b...

We analyze the observed shell gaps in N = Z nuclei determined from the binding energy differences. It is found that the shell gaps can be described by the combined contributions from the single-particle level spacing, the like-nucleon pairing, and the proton-neutron pairing interaction. This conclusion is consistent with that of Chasman in Phys. Rev. Lett. 99 (2007) 082501. For the double-close...

We investigate the Bose-Hubbard chain in presence of nearest-neighbor pairing. The pairing term gives rise to an unusual gapped ${\mathbb{Z}}_{2}$ Ising phase that has number fluctuation but no off-diagonal long range order. This a strongly correlated many-body doubly degenerate ground state which is effectively gap-protected macroscopic qubit. In interacting limit, system can be mapped onto an...

Surface properties of neutron-neutron (T=1) pairing in semi-infinite nuclear matter in a hard wall potential are investigated in BCS approximation using the Gogny force. Surface enhancement of the gap function, pairing tensor and correlation energy density is put into evidence. The possibility of producing exotic nuclei has spurred an intense revival in nuclear structure research. Among many in...

We study the pairing Hamiltonian in a set of non degenerate levels. First, we review in the path integral framework the spontaneous breaking of the U (1) symmetry occurring in such a system for the degenerate situation. Then the behaviors with the coupling constant of the ground state energy in the multilevel and in the degenerate case are compared. Next we discuss, in the multilevel case, an e...

In a schematic model with equidistant fourfold degenerate single-nucleon levels, an isovector pairing force acting only on pairs with time-reversed orbits and spins, and a symmetry force, the RPA correlation energy rises almost linearly with the isospin T , thus producing a Wigner term in accordance with the empirical proportionality of the symmetry energy to T (T + 1). Nearly symmetric nuclei ...