Equation 15 · Part 4 · Decoherence: The Quiet Selection That Makes the World Look Solid
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=
What this part means
The expressions on both sides represent the same quantity under the stated assumptions.
Its job in the formula
The equals sign connects the complete expression on the left with the complete expression on the right. Both sides must have compatible units.
Full expression→=→Article meaning
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
An equals sign says that the expression on its left and the expression on its right have the same value under the stated definitions and assumptions.
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Sources cited in the surrounding passage
These citations provide research context; check each source for the exact claim it supports.