122028642
The effect of the tensor force on the bubble structure in Ar isotopes
Abstract.The tensor force effect on the proton bubble structure of Ar isotopes is investigated in the framework of the Hartree-Fock-Bogoliubov (HFB) approach with the Skyrme interactions SLy5+T and SLy5+Tw. It is shown that the tensor force effect of the SLy5+Tw interaction favors the bubble structure of 44-56Ar due to the inversion between the proton single-particle states $ 2s_{1/2}$ and $ 1d_{3/2}$ ( $ 2s_{1/2}$ -1d3/2 inversion). However, the SLy5+T interaction cannot lead to any $ 2s_{1/2}$ -1d3/2 inversion of Ar isotopes, consequently, no bubble structure can be found in the isotopes. In addition, taking 46Ar as an example, the competition between the tensor force and pairing interaction on the bubble formation is examined in order to understand the bubble formation mechanism.
109237518
Tester Board for testing mass-produced SMB modules for CMS Preshower
We have developed a Tester Board to test the electrical characteristics of the System Motherboard (SMB) for the CMS Preshower detector at CERN. The board is designed to test input resistances, output resistances, connections, interconnections and possible short- circuits of a module having up to 640 connector pins. The Tester Board is general-purpose in nature: it could be used to test any electronic module or cable by using dedicated cable sets. The module can detect a variety of problems not detected by either functional tests or the flying probes technique. The design, algorithms and results of using the Tester Board during mass production of CMS Preshower SMBs are presented.
119273335
D2 Chern-Simons Gravity
We study the theory that contains two spin-2 fields. This theory can be regarded as a simplified version of higher spin gravity in AdS3. It can be formulated either in the first order formulation or in the second order formulation. From the first order formulation we construct the black holes in the theory and study the thermodynamics of this black holes with the help of dual holographic OPE. From the higher spin point of view, this black hole is most naturally regarded as a black hole with a spin-2 hair. In the second order formulation, we obtain an action for the metric and extra spin-2 fields and analyze the corresponding black holes. Even though for some simple cases, the conventional notions, such as the horizon, may help us to read part of the information of the black hole, they break down in generic cases. On the other hand, the action in the second order formulation could be rewritten in the form of a decoupled AdS3 bi-gravity. Moreover, the entropy of the black hole with the spin-2 hair could be reproduced from the AdS3 bi-gravity in the Euclidean path-integral formalism.
13890255
Some issues concerning holographic dark energy
We study the perturbation of holographic dark energy and find it to be stable. We study the fate of the universe when interacting holographic dark energy is present, and discuss a simple phenomenological classification of the interacting holographic dark energy models. We also discuss the cosmic coincidence problem in the context of holographic dark energy. We find that the coincidence problem cannot be completely solved by adding an interacting term. Inflation may provide a better solution of the coincidence problem.
120127236
Systematic study of tensor effects in shell evolution
In the framework of the Hartree-Fock-Bogoliubov approach with the Skyrme interactions SLy5, SLy5+T, SLy5+T{sub w}, and several sets of the TIJ parametrizations (Skyrme effective interaction parametrizations including the tensor terms), the effect of the tensor force on the shell evolution at Z,N=8, 20, and 28 is investigated. It is shown that the evolution of the gap (defined as the energy difference between the last occupied and first unoccupied single-particle orbits) with SLy5+T is similar to that with SLy5+T{sub w}, and the gap values with SLy5+T are smaller than those with SLy5+T{sub w} in the cases of Z,N=8, 20. At Z, N = 28, the gap values with SLy5 are smaller than those with SLy5+T and larger than those with SLy5+T{sub w}. To understand these features, we analyze the spin-orbit potentials with and without the tensor contributions and the radial wave functions of relevant orbits. Meanwhile, we find that the deviation of the calculated gaps with SLy5+T{sub w} from the experimental ones is larger than that with SLy5+T. This indicates that SLy5+T{sub w} is not suitable for investigating the properties of the ground-state gap evolution. Finally, it is seen that the gap evolutions with different sets of the TIJ parametrizations aremore » similar to each other except for the ones with T22, and there is almost no difference between the tensor effect in gap evolution with the perturbative method and the one with the complete fitting method.« less
124635518
Tensor effects on the proton sd states in neutron-rich Ca isotopes and bubble structure of exotic nuclei
In the framework of the Hartree-Fock-Bogoliubov (HFB) approach with Skyrme interactions SLy5+T, SLy5+T-omega and several sets of the TIJ parametrizations, the evolution of the proton single-particle energy difference between the 2s(1/2) and 1d(3/2) orbits in Ca isotopes is investigated for the cases with and without the tensor force. It is shown that the energy difference evolution trends by using different Skyrme interactions without the tensor force are similar to each other. However, the energy differences are obviously influenced by the tensor force. Meanwhile, it is found that the inversion between the two orbits (2s(1/2)-1d(3/2) inversion) induced by the tensor force occurs around Ca-48 (by SLy5+T-omega) as well as in the nuclei very far from the stability. We understand the inversion phenomenon by analyzing the tensor contributions to the spin-orbit potentials and the radial wave functions of the two orbits. Finally, the proton density distributions of Ar-46 and Hg-206 are calculated by using several sets of Skyrme interactions with and without the tensor component. It is found that the parametrization SLy5+T-omega favors the bubble structure of Ar-46 resulting from the 2s(1/2)-1d(3/2) inversion. However, for Hg-206 any tensor parametrizations do not favor its bubble structure.
119287472
Inhomogeneous vacuum energy
Vacuum energy remains the simplest model of dark energy which could drive the accelerated expansion of the Universe without necessarily introducing any new degrees of freedom. Inhomogeneous vacuum energy is necessarily interacting in general relativity. Although the 4-velocity of vacuum energy is undefined, an interacting vacuum has an energy transfer and the vacuum energy defines a particular foliation of spacetime. In particular we will discuss cosmological solutions where the background vacuum energy is spatially homogeneous. It is possible to give a consistent description of vacuum dynamics and in particular the relativistic equations of motion for spatially inhomogeneous perturbations given a covariant prescription for the vacuum energy, or equivalently the energy transfer 4-vector, and we construct gauge-invariant vacuum perturbations. We show that any dark energy cosmology can be decomposed into an interacting vacuum+matter cosmology whose inhomogeneous perturbations obey simple first-order equations.