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I was looking at this scientific paper(https://arxiv.org/abs/1205.1684) and I saw them use the symbol "K" for a nemerical value, but due to the context of the paper I wasn't sure if they were talking about kelvin or field strength, do people ever measure the strength of any electromagnetic field in "k" or does it always mean kelvin? or can it mean field strengh? I have a tendency to overthink things, I just want to be certain what they mean by "K", that way I way I better interpret the data given in this paper, I'm an amateur physicist as a hobby and I like to read this stuff even if it involves going way over my head...

Qmechanic
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Max
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    It isn't clear from the context given if this is relevant but $\mathbf{K}$ is used for a surface current density (rather than $\mathbf{J}$ for 'ordinary' current density). – Alfred Centauri Jan 14 '18 at 01:21
  • It is worth looking closely at the typesetting of the symbol if it is found in a book or a high quality on-line manuscript because it is typical to use slanted or italic type for variable and constants ($t$, $G$, or in this case $K$) and to use up-right script for units ($\mathrm{T}$, $\mathrm{Hz}$, or $\mathrm{K}$). – dmckee --- ex-moderator kitten Jan 14 '18 at 04:30
  • Impossible to answer without seeing the sentence or table where it appears. – Mitchell Porter Jan 14 '18 at 08:27
  • this is the paper, second page on the chart https://arxiv.org/pdf/1205.1684.pdf – Max Jan 16 '18 at 18:11

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I've seen capital-K used to mean thousands of different things in different physics papers. There just aren't enough letters in the alphabet to reserve capital-K for only one thing.

I'd say the 2nd most common meaning of K in physics, after kelvin, is to denote a wavevector or wavenumber. These would more commonly be written lower-case-k, but occasionally they are written capital-K (and occasionally they are other letters entirely!)

Maybe the 3rd most common meaning of K is just as a generic variable or constant or unknown in an equation.

Steve Byrnes
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  • Many recent introductory texts use $K$ for the kinetic energy (and that is certainly more obvious to native English speakers than the $T$ that I grew up with). But in any high quality text the reader should be able to reliably distinguish the use as a unit from that as a variable from the typesetting. – dmckee --- ex-moderator kitten Jan 14 '18 at 04:32
  • this is where it's used, second page om the chart https://arxiv.org/pdf/1205.1684.pdf – Max Jan 16 '18 at 18:13
  • in the arxiv paper you link, it looks like kelvins to me, if I understand you correctly. – Steve Byrnes Jan 17 '18 at 01:21