2,816 research outputs found
The Baryon-Dark Matter Ratio Via Moduli Decay After Affleck-Dine Baryogenesis
Low-scale supersymmetry breaking in string motivated theories implies the
presence of O(100) TeV scale moduli, which generically lead to a significant
modification of the history of the universe prior to Big Bang Nucleosynthesis.
Such an approach implies a non-thermal origin for dark matter resulting from
scalar decay, where the lightest supersymmetric particle can account for the
observed dark matter relic density. We study the further effect of the decay on
the baryon asymmetry of the universe, and find that this can satisfactorily
address the problem of the over-production of the baryon asymmetry by the
Affleck-Dine mechanism in the MSSM. Remarkably, there is a natural connection
between the baryon and dark matter abundances today, which leads to a solution
of the `Cosmic Coincidence Problem'.Comment: 12 pages, no figure. v2: references adde
Green and low-cost synthesis of LiNi<sub>0.8</sub>Co<sub>0.15</sub>Al<sub>0.05</sub>O2 cathode material for Li-ion batteries
Relations between entanglement, Bell-inequality violation and teleportation fidelity for the two-qubit X states
Based on the assumption that the receiver Bob can apply any unitary
transformation, Horodecki {\it et al.} [Phys. Lett. A {\bf 222}, 21 (1996)]
proved that any mixed two spin-1/2 state which violates the Bell-CHSH
inequality is useful for teleportation. Here, we further show that any X state
which violates the Bell-CHSH inequality can also be used for nonclassical
teleportation even if Bob can only perform the identity or the Pauli rotation
operations. Moreover, we showed that the maximal difference between the two
average fidelities achievable via Bob's arbitrary transformations and via the
sole identity or the Pauli rotation is 1/9.Comment: 5 pages, to be published in "Quantum Information Processing
STM characterization of the Si-P heterodimer
We use scanning tunneling microscopy (STM) and Auger electron spectroscopy to
study the behavior of adsorbed phosphine (PH) on Si(001), as a function
of annealing temperature, paying particular attention to the formation of the
Si-P heterodimer. Dosing the Si(001) surface with 0.002 Langmuirs of
PH results in the adsorption of PH (x=2,3) onto the surface and
some etching of Si to form individual Si ad-dimers. Annealing to 350C
results in the incorporation of P into the surface layer to form Si-P
heterodimers and the formation of short 1-dimensional Si dimer chains and
monohydrides. In filled state STM images, isolated Si-P heterodimers appear as
zig-zag features on the surface due to the static dimer buckling induced by the
heterodimer. In the presence of a moderate coverage of monohydrides this static
buckling is lifted, rending the Si-P heterodimers invisible in filled state
images. However, we find that we can image the heterodimer at all H coverages
using empty state imaging. The ability to identify single P atoms incorporated
into Si(001) will be invaluable in the development of nanoscale electronic
devices based on controlled atomic-scale doping of Si.Comment: 6 pages, 4 figures (only 72dpi
A REAL TIME MONITORING MODEL OF THE CALCIUM CARBONATE FOULING INDUCTION PERIOD BASED ON THE CONDUCTANCE TITRATION
A new method has been developed to monitor the calcium carbonate fouling induction period (CCFIP) in real time. Based on the conductance titration, this paper investigated the forming process of CCFIP by a staticdynamic combined simulation experiment unit. With the help of titration analysis (that is titrimetry), an accurate definition of CCFIP and the corresponding real time monitoring model were built up. The investigation results show that the proposed model applies not only to measure the CCFIP in real time, but also applies to an investigation of the influence of various factors on the CCFIP
State transfer in dissipative and dephasing environments
By diagonalization of a generalized superoperator for solving the master
equation, we investigated effects of dissipative and dephasing environments on
quantum state transfer, as well as entanglement distribution and creation in
spin networks. Our results revealed that under the condition of the same
decoherence rate , the detrimental effects of the dissipative
environment are more severe than that of the dephasing environment. Beside
this, the critical time at which the transfer fidelity and the
concurrence attain their maxima arrives at the asymptotic value
quickly as the spin chain length increases. The transfer
fidelity of an excitation at time is independent of when the system
subjects to dissipative environment, while it decreases as increases when
the system subjects to dephasing environment. The average fidelity displays
three different patterns corresponding to , and . For
each pattern, the average fidelity at time is independent of when the
system subjects to dissipative environment, and decreases as increases when
the system subjects to dephasing environment. The maximum concurrence also
decreases as increases, and when , it arrives at an
asymptotic value determined by the decoherence rate and the structure
of the spin network.Comment: 12 pages, 6 figure
Smooth Paths on Three Dimensional Lattice
A particular class of random walks with a spin factor on a three dimensional
cubic lattice is studied. This three dimensional random walk model is a simple
generalization of random walk for the two dimensional Ising model. All critical
diffusion constants and associated critical exponents are calculated. Continuum
field theories such as Klein-Gordon, Dirac and massive Chern-Simons theories
are constructed near several critical points.Comment: 7 pages,NUP-A-94-
Multi-scale assembly of hydrogels formed by highly branched arabinoxylans from Plantago ovata seed mucilage studied by USANS/SANS and rheology
© 2018 Elsevier Ltd The structures of two hydrogels formed by purified brush-like polysaccharides from Plantago ovata seed mucilage have been characterised from the nanometre to micrometre scale by using a combination of SANS and USANS techniques. These two hydrogels have distinctly different melting and rheological properties, but the structure of their gel networks bears striking similarity as revealed by USANS/SANS experiments. Surprisingly, we find that the dramatic changes in the rheological properties induced by temperature or change in the solvent quality are accompanied by a small alteration of the network structure as inferred from scattering curves recorded above melting or in a chaotropic solvent (0.7 M KOD). These results suggest that, in contrast to most gel-forming polysaccharides for which gelation depends on a structural transition, the rheological properties of Plantago ovata mucilage gels are dependent on variations in intermolecular hydrogen bonding. By enzymatically cleaving off terminal arabinose residues from the side chains, we have demonstrated that composition of side-chains has a strong effect on intermolecular interactions, which, in turn, has a profound effect on rheological and structural properties of these unique polysaccharides
Approach to the semiconductor cavity QED in high-Q regimes with q-deformed boson
The high density Frenkel exciton which interacts with a single mode
microcavity field is dealed with in the framework of the q-deformed boson. It
is shown that the q-defomation of bosonic commutation relations is satisfied
naturally by the exciton operators when the low density limit is deviated. An
analytical expression of the physical spectrum for the exciton is given by
using of the dressed states of the cavity field and the exciton. We also give
the numerical study and compare the theoretical results with the experimental
resultsComment: 6 pages, 2 figure
Electronic structure of nuclear-spin-polarization-induced quantum dots
We study a system in which electrons in a two-dimensional electron gas are
confined by a nonhomogeneous nuclear spin polarization. The system consists of
a heterostructure that has non-zero nuclei spins. We show that in this system
electrons can be confined into a dot region through a local nuclear spin
polarization. The nuclear-spin-polarization-induced quantum dot has interesting
properties indicating that electron energy levels are time-dependent because of
the nuclear spin relaxation and diffusion processes. Electron confining
potential is a solution of diffusion equation with relaxation. Experimental
investigations of the time-dependence of electron energy levels will result in
more information about nuclear spin interactions in solids
- …