Cheshire cat

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Cheshire cat

One who is smiling smugly or mischievously. The term was popularized by the character in Lewis Carroll's Alice's Adventures in Wonderland. I knew he had a prank planned for April Fools' Day when he arrived at work grinning like a Cheshire cat.
See also: cat, Cheshire
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

Cheshire cat

Having a perpetual, mischievous grin, one that is often indistinguishable from smugness. Although the Cheshire cat is best known as a character in Lewis Carroll's Alice's Adventures in Wonderland, it appeared much earlier in popular English culture, so the phrase may have originally referred to cheese made in the country of Cheshire and molded roughly to resemble a grinning cat. Lewis Carroll's feline had the ability to disappear until only its smile remained. The cheese variety would be sliced from hind end to front, which similarly gave the impression that its smile—if cheese showed emotion—would be the last to go.
See also: cat, Cheshire
Endangered Phrases by Steven D. Price Copyright © 2011 by Steven D. Price
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References in periodicals archive ?
The archetype of the quantum Cheshire Cat paradox proposed in [3] is a two-path Mach-Zehnder-like setting for a photon with an internal degree of freedom, the polarization.
As detection of the Cheshire Cat requires simultaneous measurement for both paths of the photon, one applies there the weak measurement scheme [3,7].
For the quantum Cheshire Cat experiment, with given pre- (see (1)) and postselected (see (2)) states, one obtains [3]
Let us emphasize that our primary aim is to present that the Cheshire Cat effect, in its archetype formulated using quantum weak values, survives in the presence of decoherence of a certain, relatively general, type.
However, the weak values which are a figure of merit for the Cheshire Cat paradox become modified by decoherence
The original quantum Cheshire Cat originates from a very peculiar asymmetry between initial preparation (preselection) of the system having internal degree of freedom and its postselection via a very specific measurement scheme.
Let us also notice that due to the asymmetry the Cheshire Cat effect survives also in the presence of decoherence in an apparent contrast to some other quantum effects for which decherence can be lethal.
An effect of (pure) decoherence on the Cheshire Cat paradox is fully governed by a quantity
It follows from the discussion that the Cheshire Cat effect is preserved in symmetric pure dephasing environments.
Studying of the quantity [Q.sub.[+ or -]] in (29) allows filling with a physical content formulas of the previous section where we present how an arbitrary local decohernce affects the Cheshire Cat. We plot the amplitude [PHI][+ or -] and the phase [K.sub.[+ or -]] as a function of time in (a) and (b) of Figure 1.
The effect of dissipation on the Cheshire Cat paradox is again governed by a quantity
Although the time integral in (36) requires numerical evaluation, one concludes that a (small) dissipation rate impacts, according to (35), only qualitatively the "paradoxial" properties of the Cheshire Cat [3] as it was the case for a (symmetric) pure decoherence (cf.
However, the Cheshire Cat experiment is performed in a relatively short time scale related to a passage of photos via an interferometer [6] and the Davies approximation is not optimal.
There is an unavoidable influence of an environment on any experimental investigation of the quantum Cheshire Cat behaviour [6].
"They are called Cheshire Cats because they have a picture of a grinning cat on them - and I believe they make the user look pretty much like one too.
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