'Strange metals' point to a whole new way to understand electricity
18 comments
·May 25, 2025kens
s1mplicissimus
afaiu quadratic is a subtype of exponential, so they are not mutually exlusive
Sniffnoy
No. Exponential growth or decay is much faster than quadratic growth or decay. You may be mixing up exponential functions, of the form x maps to ab^x, with power functions, of the form x maps to ax^b. These are very different!
Annoyingly, people often use "exponential" colloquially to mean anything faster than linear, but in fact lots of things are faster than linear.
fwip
If I'm reading Wikipedia correctly, the formula is quadratic for some metals, and cubic or quintuplic(?) for others: https://en.wikipedia.org/wiki/Electrical_resistivity_and_con...
VygmraMGVl
Typically, the behavior of any given metal is a mix of mechanisms so the measured behavior is fit to a curve where you fit n. So for metals the exponent is typically a decimal between 2 and 5.
fwip
Thanks, I appreciate the explanation. :)
Sniffnoy
You would normally just say "5th degree" or "5th power".
dinfinity
IANAP, but I thought that quantum field theory (which isn't incredibly controversial) already treats particles as merely emergent convenient ways to describe common excitations of the fields. I'm surprised it isn't mentioned here at all.
tux3
A regular particle isn't really emergent, it corresponds 1:1 to the excitation of the field
Quasiparticles arise out of a collection of particles, that's why they're emergent
dinfinity
> A regular particle isn't really emergent, it corresponds 1:1 to the excitation of the field
Maybe 'emergent' was the wrong word here. I meant that particles are convenient ways of describing behavior of the fields in many (but not all) cases, with the fields themselves considered to be the (more) fundamental description of reality.
colechristensen
Eh, in the wave-particle duality wars you may have been swayed a bit too strongly into the wave camp.
Quantization exists and isn't just a convenience.
jfengel
QFT is perfect for a single particle, but it gets harder to describe the behavior of particles en masse. It's super hard to find simplifications that reveal emergent behavior.
countWSS
so electrons are just like photons being a wave/particle? The article seems to suggest in strange metals their particle properties are absent and only 'electron field' gradients move, like if electrons exhanged their 'charge'.
rnhmjoj
Electrons are not just like photons. It's tempting to say that, but there are some significant differences that can lead you in error if you think in this picture.
First of all, if you think of a photon as some small ball, not that's not what it is. Mathematically a photon is defined as a state of the EM field (which has been quantised into a set of harmonic oscillators called "normal modes") in which there is exactly one quantum of excitation of a specific normal mode (with given wavevector and frequency). Depending on which kind of modes you consider, a photon could be a gaussian beam, or even a plane wave, so not something localised like you would say of a particle.
Unlike photons, electrons have a position operator, so in principle you can measure and say where one electron is. The same is impossible for photons. Also electrons have a mass, but photon are massless. This means you can have motionless electrons, but this is impossible for photons: they always move at the speed of light. Electrons have a non-relativistic classical limit, while photon do not.
W. E. Lamb used to say that people should be required a license for the use of the word "photon", because it can be very misleading.
toast0
Yeah, electrons are waves and experience quantum tunneling which we see in high density electronics and specifically apply in flash memories.
ChrisClark
Yeah, everything is just like photons, everything is a wave/particle
The article says that resisivity in normal metals follows a quadratic curve, but the article also says that it follows an exponential curve. Does anyone know which it right?