43,368 research outputs found
Invariant information and complementarity in high-dimensional states
Using a generalization of the invariant information introduced by Brukner and
Zeilinger [Phys. Rev. Lett. \textbf{83}, 3354 (1999)] to high-dimensional
systems, we introduce a complementarity relation between the local and nonlocal
information for systems under the isolated environment, where
is prime or the power of prime. We also analyze the dynamics of the local
information in the decoherence process.Comment: 4 pages, 2 figure
Relation between two measures of entanglement in spin-1/2 and spinless fermion quantum chain systems
The concepts of concurrence and mode concurrence are the measures of
entanglement for spin-1/2 and spinless fermion systems respectively. Based on
the Jordan-Wigner transformation, any spin-1/2 system is always associated with
a fermion system (called counterpart system). The comparison of concurrence and
mode concurrence can be made with the aid of the Marshall's sign rule for the
ground states of spin-1/2 and spinless fermion chain systems. We observe
that there exists an inequality between concurrence and mode concurrence for
the ground states of the two corresponding systems. The spin-1/2 XY chain
system and its spinless fermion counterpart as a realistic example is discussed
to demonstrate the analytical results.Comment: 7 pages, no figures, publication version, to appear in PR
Enhanced mechanical stability of Ni-YSZ scaffold demonstrated by nanoindentation and electrochemical impedance spectroscopy
The electrochemical performance of Ni-YSZ SOFC anodes can quickly degrade during redox cycling. Mechanical damage at interfaces significantly decreases the number of active triple phase boundaries. This study firstly focuses on the sintering temperature impact on YSZ scaffold mechanical properties. The YSZ scaffold sintered at 1200 °C exhibited 56% porosity, 28.3 GPa elastic modulus and 0.97 GPa hardness and was selected for further redox cycling study. The Ni infiltrated YSZ scaffold operated at 550 °C had an initial stabilized polarisation resistance equal to 0.62 Ω cm2 and only degraded to 2.85 Ω cm2 after 15 redox cycles. The active triple phase boundary density was evaluated by FIB-SEM tomography, and degraded from 28.54 μm−2 to 19.36 μm−2. The YSZ scaffold structure was robust after 15 redox cycles, as there was no observation of the framework fracturing in both SEM and FIB-SEM images, which indicated that the mechanical stability of YSZ scaffold improves the anode stability during redox cycling. Nonetheless, Ni agglomeration could not be prevented within Ni-YSZ scaffolds and this needs further consideration
On the transport and thermodynamic properties of quasi-two-dimensional purple bronzes AMoO (A=Na, K)
We report a comparative study of the specific heat, electrical resistivity
and thermal conductivity of the quasi-two-dimensional purple bronzes
NaMoO and KMoO, with special emphasis on
the behavior near their respective charge-density-wave transition temperatures
. The contrasting behavior of both the transport and the thermodynamic
properties near is argued to arise predominantly from the different
levels of intrinsic disorder in the two systems. A significant proportion of
the enhancement of the thermal conductivity above in
NaMoO, and to a lesser extent in KMoO, is
attributed to the emergence of phason excitations.Comment: 8 pages, 6 figures, To appear in Physical Review
q-Deformation of W(2,2) Lie algebra associated with quantum groups
An explicit realization of the W(2,2) Lie algebra is presented using the
famous bosonic and fermionic oscillators in physics, which is then used to
construct the q-deformation of this Lie algebra. Furthermore, the quantum group
structures on the q-deformation of this Lie algebra are completely determined.Comment: 12 page
Wetting and bonding characteristics of selected liquid-metals with a high power diode laser treated alumina bioceramic
Changes in the wettability characteristics of an alumina bioceramic occasioned by high power diode laser (HPDL) surface treatment were apparent from the observed reduction in the contact angle. Such changes were due to the HPDL bringing about reductions the surface roughness, increases in the surface O2 content and increases in the polar component of the surface energy. Additionally, HPDL treatment of the alumina bioceramic surface was found to effect an improvement in the bonding characteristics by increasing the work of adhesion. An electronic approach was used to elucidate the bonding characteristics of the alumina bioceramic before and after HPDL treatment. It is postulated that HPDL induced changes to the alumina bioceramic produced a surface with a reduced bandgap energy which consequently increased the work of adhesion by increasing the electron transfer at the metal/oxide interface and thus the metal-oxide interactions. Furthermore, it is suggested that the increase in the work of adhesion of the alumina bioceramic after HPDL treatment was due to a correlation existing between the wettability and ionicity of the alumina bioceramic; for it is believed that the HPDL treated surface is less ionic in nature than the untreated surface and therefore exhibits better wettability characteristics
Very Long Baseline Array observations of the Intraday Variable source J1128+592
Short time-scale flux density variations of flat spectrum radio sources are
often explained by the scattering of radio waves in the turbulent, ionized
Interstellar Matter of the Milky Way. One of the most convincing observational
arguments in favor of this is the annual modulation of the variability
time-scale caused by the Earth orbital motion around the Sun. J1128+592 is an
IDV source with a possible annual modulation in its variability time-scale. We
observed the source in 6 epochs with the VLBA at 5, 8 and 15 GHz in total
intensity and polarization. The VLBA observations revealed an east-west
oriented core-jet structure. Its position angle agrees with the angle of
anisotropy derived from the annual modulation model. No significant long-term
structural changes were observed with VLBI on mas-scales, however, compared to
archival data, the VLBI core size is expanded. This expansion offers a possible
explanation to the observed decrease of the strength of IDV. VLBI polarimetry
revealed significant changes in the electric vector position angle and Rotation
Measure of the core and jet. Part of the observed RM variability could be
attributed to a scattering screen (37 pc distance), which covers the source
(core and jet) and which may be responsible for the IDV. Superposition of
polarized sub-components below the angular resolution limit may affect the
observed RM as well.Comment: accepted for A&A (11 pages, 11 figures
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