Equation 15 · Part 3 · Decoherence: The Quiet Selection That Makes the World Look Solid
Symbol Lambda
What this part means
what Joos and Zeh call the localization rate: a single number.
Its job in the formula
Lambda is one of the signed contributions combined to compute the quantity on the left.
Full expression→Symbol Lambda→Article meaning
Where the article explains it
Here is what Joos and Zeh call the localization rate: a single number, with units of inverse length squared per unit time, built from the scattering cross-section of the object, the flux and momentum of whatever is doing the scattering, and nothing else [ 7 ] .
The passage around this formula
The same paper also tracks what happens to the coherence length itself, not just the decay rate: solving the full master equation for a free particle gives a coherence width l(t) = (8 t)^{-1/2} , meaning it shrinks as the inverse square root of time for as long as scattering dominates, and does so from whatever width the particle’s wave packet started with [ 7 ] . Joos and Zeh flag the counterintuitive consequence themselves: the everyday expectation that a free wave packet spreads out over time is not what this equation describes at all. “The much-discussed dispersion hardly ever shows up even for small dust particles or large molecules,” they write; instead “the coherence length…
Learn the underlying idea
A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.
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Sources cited in the surrounding passage
These citations provide research context; check each source for the exact claim it supports.