3,828 research outputs found
Separability for lattice systems at high temperature
Equilibrium states of infinite extended lattice systems at high temperature
are studied with respect to their entanglement. Two notions of separability are
offered. They coincide for finite systems but differ for infinitely extended
ones. It is shown that for lattice systems with localized interaction for high
enough temperature there exists no local entanglement. Even more quasifree
states at high temperature are also not distillably entangled for all local
regions of arbitrary size. For continuous systems entanglement survives for all
temperatures. In mean field theories it is possible, that local regions are not
entangled but the entanglement is hidden in the fluctuation algebra
Soil surface albedo and multispectral reflectance of short-wave radiation as a function of degree of soil slaking.
The feasibility of mapping the degree of soil slaking using remote sensing on the basis of reflected solar radiation was investigated in the laboratory. Relationships between soil surface reflection and wavelength of light were plotted for a range of soil moisture contents and degrees of soil slaking. Reflection tended to increase with decreasing moisture content. Slaking had little effect on reflection at high moisture contents, but slightly increased reflection at low moisture contents. The detection of slaking by spectral analysis is not recommended, while albedo measurements may be successful under dry conditions. (Abstract retrieved from CAB Abstracts by CABI’s permission
Codes on Graphs: Observability, Controllability, and Local Reducibility
Original manuscript: August 30, 2012This paper investigates properties of realizations of linear or group codes on general graphs that lead to local reducibility. Trimness and properness are dual properties of constraint codes. A linear or group realization with a constraint code that is not both trim and proper is locally reducible. A linear or group realization on a finite cycle-free graph is minimal if and only if every local constraint code is trim and proper. A realization is called observable if there is a one-to-one correspondence between codewords and configurations, and controllable if it has independent constraints. A linear or group realization is observable if and only if its dual is controllable. A simple counting test for controllability is given. An unobservable or uncontrollable realization is locally reducible. Parity-check realizations are controllable if and only if they have independent parity checks. In an uncontrollable tail-biting trellis realization, the behavior partitions into disconnected sub-behaviors, but this property does not hold for nontrellis realizations. On a general graph, the support of an unobservable configuration is a generalized cycle
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