31,358 research outputs found
Reliability physics
Speakers whose topics relate to the reliability physics of solar arrays are listed and their topics briefly reviewed. Nine reports are reviewed ranging in subjects from studies of photothermal degradation in encapsulants and polymerizable ultraviolet stabilizers to interface bonding stability to electrochemical degradation of photovoltaic modules
Gauge Coupling Unification via A Novel Technicolor Model
We show that the recently proposed minimal walking technicolor theory
together with a small modification of the Standard Model fermionic matter
content leads to an excellent degree of unification of the gauge couplings. We
compare the degree of unification with various time-honored technicolor models
and the minimal supersymmetric extension of the Standard Model. We find that,
at the one-loop level, the new theory provides a degree of unification higher
than any of the other extensions above. The phenomenology of the present model
is very rich with various potential dark matter candidates.Comment: Final version to match the published on
The identification of selected vegetation types in Arizona through the photointerpretation of intermediate scale aerial photography
The author has identified the following significant results. Nine photography interpretation tests were performed with a total of 19 different interpreters. Three tests were conducted with black and white intermediate scale photography and six tests with color infrared intermediate scale photography. The black and white test results show that the interpretation of vegetation mapped at the association level of classification is reliable for all the classes used at 61%. The color infrared tests indicate that the association level of mapping is unsatisfactory for vegetation interpretation of classes 1 and 6. Students' t-test indicated that intermediate scale black and white photography is significantly better than this particular color infrared photography for the interpretation of southeastern Arizona vegetation mapped at the association level
Quantum Control Theory for State Transformations: Dark States and their Enlightenment
For many quantum information protocols such as state transfer, entanglement
transfer and entanglement generation, standard notions of controllability for
quantum systems are too strong. We introduce the weaker notion of accessible
pairs, and prove an upper bound on the achievable fidelity of a transformation
between a pair of states based on the symmetries of the system. A large class
of spin networks is presented for which this bound can be saturated. In this
context, we show how the inaccessible dark states for a given
excitation-preserving evolution can be calculated, and illustrate how some of
these can be accessed using extra catalytic excitations. This emphasises that
it is not sufficient for analyses of state transfer in spin networks to
restrict to the single excitation subspace. One class of symmetries in these
spin networks is exactly characterised in terms of the underlying graph
properties.Comment: 14 pages, 3 figures v3: rewritten for increased clarit
Classification of Standard Model Particles in Orbifold Grand Unified Theories
We classify the standard model fermions, which originate from bulk fields of
the or representation after orbifold breaking, in
grand unified theories on 5 or 6-dimensional space-time, under the
condition that , and survive as zero modes.Comment: 24 pages, typos corrected, to appear in IJMP
Apparent Violation of the Wiedemann-Franz law near a magnetic field tuned metal-antiferromagnetic quantum critical point
The temperature dependence of the interlayer electrical and thermal
resistivity in a layered metal are calculated for Fermi liquid quasiparticles
which are scattered inelastically by two-dimensional antiferromagnetic spin
fluctuations. Both resistivities have a linear temperature dependence over a
broad temperature range. Extrapolations to zero temperature made from this
linear- range give values that appear to violate the Wiedemann-Franz law.
However, below a low-temperature scale, which becomes small close to the
critical point, a recovery of this law occurs. Our results describe recent
measurements on CeCoIn near a magnetic field-induced quantum phase
transition. Hence, the experiments do not necessarily imply a non-Fermi liquid
ground state.Comment: 4 pages, 2 figures; accepted to Phys. Rev. Let
Quantum entanglement between a nonlinear nanomechanical resonator and a microwave field
We consider a theoretical model for a nonlinear nanomechanical resonator
coupled to a superconducting microwave resonator. The nanomechanical resonator
is driven parametrically at twice its resonance frequency, while the
superconducting microwave resonator is driven with two tones that differ in
frequency by an amount equal to the parametric driving frequency. We show that
the semi-classical approximation of this system has an interesting fixed point
bifurcation structure. In the semi-classical dynamics a transition from stable
fixed points to limit cycles is observed as one moves from positive to negative
detuning. We show that signatures of this bifurcation structure are also
present in the full dissipative quantum system and further show that it leads
to mixed state entanglement between the nanomechanical resonator and the
microwave cavity in the dissipative quantum system that is a maximum close to
the semi-classical bifurcation. Quantum signatures of the semi-classical
limit-cycles are presented.Comment: 36 pages, 18 figure
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