Equation 14 · Part 5 · Every Crystal Has Its Own Speed of Light
superscript
superscript
What this part means
A raised number can be a power. When it is a label or bound, it selects a case or the upper limit of a sum; the formula’s structure distinguishes these uses.
Its job in the formula
A raised mark can be a power or an index. Its position and the surrounding notation determine which.
Full expression→superscript→Article meaning
The passage around this formula
Trapped-ion chains make that material-dependence concrete, because they let experimenters dial the range of the interaction and watch the cone respond. Philip Jurcevic and collaborators encoded a tunable-range Ising model on chains of trapped calcium-40 ions, with couplings falling off as 1/|i-j|^{} for an adjustable exponent , and extracted the fastest magnon velocity the resulting dispersion supports. At short range the measured velocity agrees with the ordinary nearest-neighbour prediction; as is pushed toward zero, toward an interaction that barely decays with distance at all, the velocity is consistent with growing without bound, and the light-cone picture stops…
Learn the underlying idea
An exponent tells how a base is used in multiplication. In x³, x is the base and 3 is the exponent: x³ = x × x × x.
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Sources cited in the surrounding passage
These citations provide research context; check each source for the exact claim it supports.