15,106 research outputs found
Mean Field Theoretical Structure of He and Be Isotopes
The structures of He and Be even-even isotopes are investigated using an
axially symmetric Hartree-Fock approach with a Skyrme-IIIls mean field
potential. In these simple HF calculations, He and Be isotopes appear to be
prolate in their ground states and Be isotopes have oblate shape isomeric
states. It is also shown that there exists a level crossing when the nuclear
shape changes from the prolate state to the oblate state. The single neutron
levels of Be isotopes exhibit a neutron magic number 6 instead of 8 and show
that the level inversion between 1/2- and 1/2+ levels occurs only for a largely
deformed isotope. Protons are bound stronger in the isotope with more neutrons
while neutron levels are somewhat insensitive to the number of neutrons and
thus the nuclear size and also the neutron skin become larger as the neutron
number increases. In these simple calculations with Skyrme-IIIls interaction no
system with a clear indication of neutron halo was found among He and Be
isotopes. Instead of it we have found 8He+2n, 2n+8He+2n, and 16Be+2n like chain
structures with clusters of two correlated neutrons. It is also shown that 8He
and 14Be in their ground states are below the neutron drip line in which all
nucleons are bound with negative energy and that 16Be in its ground state is
beyond the neutron drip line with two neutrons in positive energy levels.Comment: CM energy correction, 1 figure and more discussions adde
D-outcome measurement for a nonlocality test
For the purpose of the nonlocality test, we propose a general correlation
observable of two parties by utilizing local -outcome measurements with
SU() transformations and classical communications. Generic symmetries of the
SU() transformations and correlation observables are found for the test of
nonlocality. It is shown that these symmetries dramatically reduce the number
of numerical variables, which is important for numerical analysis of
nonlocality. A linear combination of the correlation observables, which is
reduced to the Clauser-Horne-Shimony-Holt (CHSH) Bell's inequality for two
outcome measurements, is led to the Collins-Gisin-Linden-Massar-Popescu (CGLMP)
nonlocality test for -outcome measurement. As a system to be tested for its
nonlocality, we investigate a continuous-variable (CV) entangled state with
measurement outcomes. It allows the comparison of nonlocality based on
different numbers of measurement outcomes on one physical system. In our
example of the CV state, we find that a pure entangled state of any degree
violates Bell's inequality for measurement outcomes when the
observables are of SU() transformations.Comment: 16 pages, 2 figure
Origin of Anomalous Water Permeation through Graphene Oxide Membrane
Water inside the low dimensional carbon structures has been considered
seriously owing to fundamental interest in its flow and structures as well as
its practical impact. Recently, the anomalous perfect penetration of water
through graphene oxide membrane was demonstrated although the membrane was
impenetrable for other liquids and even gases. The unusual auxetic behavior of
graphene oxide in the presence of water was also reported. Here, based on
first-principles calculations, we establish atomistic models for hybrid systems
composed of water and graphene oxides revealing the anomalous water behavior
inside the stacked graphene oxides. We show that formation of hexagonal ice
bilayer in between the flakes as well as melting transition of ice at the edges
of flakes are crucial to realize the perfect water permeation across the whole
stacked structures. The distance between adjacent layers that can be controlled
either by oxygen reduction process or pressure is shown to determine the water
flow thus highlighting a unique water dynamics in randomly connected
two-dimensional spaces.Comment: 5 pages, 4 figures, to appear in Nano Letter
Entanglement transfer from continuous variables to qubits
We show that two qubits can be entangled by local interactions with an
entangled two-mode continuous variable state. This is illustrated by the
evolution of two two-level atoms interacting with a two-mode squeezed state.
Two modes of the squeezed field are injected respectively into two spatially
separate cavities and the atoms are then sent into the cavities to resonantly
interact with the cavity field. We find that the atoms may be entangled even by
a two-mode squeezed state which has been decohered while penetrating into the
cavity.Comment: 5 pages, 4 figure
Diquaternary Ammonium Compounds in Zeolite Synthesis: Cyclic and Polycyclic N-Heterocycles Connected by Methylene Chains
An additional dimension has been added to our long-standing studies in high silica zeolite synthesis via a guest/host synergism. We have created and studied the impact of making symmetric diquaternary ammonium compounds, by varying the chain length between nitrogen charge centers, and the heterocycle size and geometry containing the nitrogen. This allows the introduction of a second spatial parameter in the use of the charged organo-cation guest in the zeolite synthesis. The series of 15 diquaternary ammonium compounds (5 heterocycles synthesized onto chain lengths of C4−C6) were tested in a total of 135 zeolite syntheses reactions. Nine screening reactions were employed for each guest molecule, and the conditions built upon past successes in finding novel high silica zeolites via introduction of boron, aluminum, or germanium as substituting tetrahedral framework atoms for silicon. Eighteen different zeolite structures emerged from the studies. The use of specific chain lengths for derivatives of the pyrrolidine ring system produced novel zeolite materials SSZ-74 and 75
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