4,590 research outputs found
Metal alloy resistivity measurements at very low temperatures
High speed, automated system accurately measures to approximately one percent in three minutes. System identifies materials having constant thermal or electric conductivity, predicts new material properties, develops alloys in accordance with desired specifications, and develops nondestructive devices for measuring precipitation hardening
Scaffolds and Generalized Integral Galois Module Structure
Let be a finite, totally ramified -extension of complete local
fields with residue fields of characteristic , and let be a
-algebra acting on . We define the concept of an -scaffold on ,
thereby extending and refining the notion of a Galois scaffold considered in
several previous papers, where was Galois and for
. When a suitable -scaffold exists, we show how to
answer questions generalizing those of classical integral Galois module theory.
We give a necessary and sufficient condition, involving only numerical
parameters, for a given fractional ideal to be free over its associated order
in . We also show how to determine the number of generators required when it
is not free, along with the embedding dimension of the associated order. In the
Galois case, the numerical parameters are the ramification breaks associated
with . We apply these results to biquadratic Galois extensions in
characteristic 2, and to totally and weakly ramified Galois -extensions in
characteristic . We also apply our results to the non-classical situation
where is a finite primitive purely inseparable extension of arbitrary
exponent that is acted on, via a higher derivation (but in many different
ways), by the divided power -Hopf algebra.Comment: Further minor corrections and improvements to exposition. Reference
[BE] updated. To appear in Ann. Inst. Fourier, Grenobl
Universal quantum computation by discontinuous quantum walk
Quantum walks are the quantum-mechanical analog of random walks, in which a
quantum `walker' evolves between initial and final states by traversing the
edges of a graph, either in discrete steps from node to node or via continuous
evolution under the Hamiltonian furnished by the adjacency matrix of the graph.
We present a hybrid scheme for universal quantum computation in which a quantum
walker takes discrete steps of continuous evolution. This `discontinuous'
quantum walk employs perfect quantum state transfer between two nodes of
specific subgraphs chosen to implement a universal gate set, thereby ensuring
unitary evolution without requiring the introduction of an ancillary coin
space. The run time is linear in the number of simulated qubits and gates. The
scheme allows multiple runs of the algorithm to be executed almost
simultaneously by starting walkers one timestep apart.Comment: 7 pages, revte
The Viscosity and Thermal Conductivity Coefficients of Dilute Neon, Krypton, and Xenon
Viscosity and thermoconductivity coefficients of dilute neon, krypton, and xeno
Spatial search by quantum walk
Grover's quantum search algorithm provides a way to speed up combinatorial
search, but is not directly applicable to searching a physical database.
Nevertheless, Aaronson and Ambainis showed that a database of N items laid out
in d spatial dimensions can be searched in time of order sqrt(N) for d>2, and
in time of order sqrt(N) poly(log N) for d=2. We consider an alternative search
algorithm based on a continuous time quantum walk on a graph. The case of the
complete graph gives the continuous time search algorithm of Farhi and Gutmann,
and other previously known results can be used to show that sqrt(N) speedup can
also be achieved on the hypercube. We show that full sqrt(N) speedup can be
achieved on a d-dimensional periodic lattice for d>4. In d=4, the quantum walk
search algorithm takes time of order sqrt(N) poly(log N), and in d<4, the
algorithm does not provide substantial speedup.Comment: v2: 12 pages, 4 figures; published version, with improved arguments
for the cases where the algorithm fail
Asymptotic entanglement capacity of the Ising and anisotropic Heisenberg interactions
We compute the asymptotic entanglement capacity of the Ising interaction ZZ,
the anisotropic Heisenberg interaction XX + YY, and more generally, any
two-qubit Hamiltonian with canonical form K = a XX + b YY. We also describe an
entanglement assisted classical communication protocol using the Hamiltonian K
with rate equal to the asymptotic entanglement capacity.Comment: 5 pages, 1 figure; minor corrections, conjecture adde
Review of Repertoires and Choices in African Languages
National Foreign Language Resource Cente
Studies relating to Polyunsaturated Fatty Acid (PUFA) Supplementation and Fertility in Cattle
End of project reportReproductive inefficiency has a significant impact on the economic performance of both dairy and beef herds, particularly in seasonal calving systems. Nutrition plays a fundamental role in reproduction. Furthermore, there is emerging evidence that supplemental dietary polyunsaturated fatty acids (PUFA) may increase cow fertility independent of their role as energy substrates. A number of studies have reported enhanced reproductive performance in dairy cows following dietary supplementation with sources of n-3 PUFA. However the possible mechanisms involved have not been identified and there is some inconsistency in the published literature on this topic. The objective of the research reported was to conduct a holistic examination of the effects of dietary long-chain n-3 PUFA supplementation on metabolic and reproductive responses in cattle. Such information is essential for the appropriate formulation of diets to enhance cow reproductive performance and in particular embryo survival
Decoherent quantum walks driven by a generic coin operation
We consider the effect of different unitary noise mechanisms on the evolution
of a quantum walk (QW) on a linear chain with a generic coin operation: (i)
bit-flip channel noise, restricted to the coin subspace of the QW, and (ii)
topological noise caused by randomly broken links in the linear chain.
Similarities and differences in the respective decoherent dynamics of the
walker as a function of the probability per unit time of a decoherent event
taking place are discussed
- …