Equation 10 · Part 1 · Every Crystal Has Its Own Speed of Light
Symbol d
What this part means
the distance between the two sites on the lattice [ 1 ].
Its job in the formula
d is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Full expression→Symbol d→Article meaning
Where the article explains it
where C and are constants fixed by the microscopic couplings and d(x,y) is the distance between the two sites on the lattice [ 1 ] .
The passage around this formula
where C and are constants fixed by the microscopic couplings and d(x,y) is the distance between the two sites on the lattice [ 1 ] . Outside the cone, where d(x,y) exceeds t , the right-hand side collapses toward zero; inside it, the inequality simply has nothing to say. The velocity plays exactly the causal role the vacuum speed c plays in relativity, with one difference that matters for everything that follows: it is a property of the material, not of empty space, and it changes from one lattice to the next.
Learn the underlying idea
A function assigns an output to each allowed input. The expression f(x) means “apply f to x”.
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See this notation across published equations →
Sources cited in the surrounding passage
These citations provide research context; check each source for the exact claim it supports.