23 research outputs found

    Compactly supported linearised observables in single-field inflation

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    We investigate the gauge-invariant observables constructed by smearing the graviton and inflaton fields by compactly supported tensors at linear order in general single-field inflation. These observables correspond to gauge-invariant quantities that can be measured locally. In particular, we show that these observables are equivalent to (smeared) local gaugeinvariant observables such as the linearisedWeyl tensor, which have better infrared properties than the graviton and inflaton fields. Special cases include the equivalence between the compactly supported gauge-invariant graviton observable and the smeared linearised Weyl tensor in Minkowski and de Sitter spaces. Our results indicate that the infrared divergences in the tensor and scalar perturbations in single-field inflation have the same status as in de Sitter space and are both a gauge artefact, in a certain technical sense, at tree level

    Shared genetic risk between eating disorder- and substance-use-related phenotypes:Evidence from genome-wide association studies

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    First published: 16 February 202

    Study of grain boundary segregation using the Auger electron emission technique. Annual technical progress report, VII, January 1, 1977--December 31, 1977

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    An analysis of plastic flow at the tip of a propagating crack during brittle fracture has been developed. The plastic flow analysis takes into account the anisotropy of slip by a mixed mode opening scheme. Values of the true fracture energy for different crack systems are obtained; the effects of an embrittling agent can be taken into account. The fracture stresses of Cu--Bi alloys having varied grain sizes and Bi concentrations were measured. Dilute alloys exhibited a decreasing fracture stress with decreasing grain size. Auger analysis indicated a large variation of Bi segregated to boundaries in coarse grained materials with smaller variations in fine grained material. The grain boundary diffusion of nickel was studied in the Cu--Bi alloy system by means of Auger spectroscopy. Bi retards boundary diffusion of Ni; however, the results are quite complex since the Ni presence alters the Bi concentration at the boundary. The Bi concentration tends to decrease to a value approximately equal to that of Ni. Possible effects of solute segregation in determining SCC susceptibility of copper alloys in acid sulfate solution were examined with high purity binary alloys. Grain boundary segregation of Sb and Bi in Cu promoted intergranular SCC in sulfuric acid. Cracking was macroscopically brittle, but significant dissolution occurred along the intergranular crack path. Electrochemical measurements revealed an active path for SCC in segregated Cu--Sb and Cu--Bi alloys. Grain boundary segregation has no effect on the bulk electrochemical properties of unstressed Cu--Sb and Cu--Bi
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