
Study finds billions of quantum entangled electrons in 'strange metal' - hhs
https://phys.org/news/2020-01-strange-metals.html
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slowmovintarget
> "When we think about quantum entanglement, we think about small things," Si
> said. "We don't associate it with macroscopic objects. But at a quantum
> critical point, things are so collective that we have this chance to see the
> effects of entanglement, even in a metallic film that contains billions of
> billions of quantum mechanical objects."

Maybe the mistake is us thinking there is a "quantum level". Rather, quantum
mechanical effects are actually real and not just math. Einstein argued this
all those years ago, but lost the argument to Neils Bohr at the time (not on
the merits of the argument, but by the politics of scientific establishment).
John Bell and others have showed the merit in Einstein's viewpoint.

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peter_d_sherman
Excerpt:

"Fermi-liquid theory predicts that, at low temperatures, the resistance of
metals should depend on the square of temperature. However, cuprates’
resistance varies linearly with temperature down to the point at which they
become superconducting."

...Interesting!

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snissn
I could never understand the part of quantum where only two particles could be
entangled at a time with each other and multiple particles couldn't be
entangled together.

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hnews_account_1
Multiple particle entanglement is the common state. 2 particle entanglement is
a special state achieved for research and manipulative purposes. A quantum
computer is made up with multiple particles being entangled. If they didn't,
the speedup would only be a parallelised version of a 4x speed normal
computation.

~~~
PaulHoule
Actually quantum entanglement is the reason why solids are solid (fermi
statistics) and why lasers are coherent (bose statistics.)

The point of quantum entanglement is that it is not right to plot the
wavefunctions for separate electrons (e.g. quarks, photons, ...) but rather
you have a wavefunction for all of the electrons at once -- for N electrons
the arguments of the wavefunction could be the positions of the N particles
(or the momentum)

It's that way all the time, whether people are doing an experiment to
demonstrate entanglement or not. The "solid matter" and "laser" effects happen
because of the two possible symmetries when you swap two of the particles --
either the wave function stays the same when you swap two particles (photons)
or it goes 180 out of phase (electrons)

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hnews_account_1
I don't know if EM phase coherence is a question of quantum entanglement. I
think it can be achieved regardless of it i.e. if a laser was made of
unentangled photons that just happened to be in phase, it'd still function as
a laser. Imagine if all the photons in a laser are entangled: it'd mean any
partial interference with the laser would interfere with the whole wave ..
which, correct me if I'm wrong, but I don't think that happens.

Like not all lasers are bose einstein condensates, though lasers can be made
from the emissions of such a state. I could be entirely wrong about this. It's
been a while since I went back to quantum physics.

~~~
PaulHoule
See

[https://en.wikipedia.org/wiki/Bose%E2%80%93Einstein_statisti...](https://en.wikipedia.org/wiki/Bose%E2%80%93Einstein_statistics)

"The aggregation of particles in the same state, which is a characteristic of
particles obeying Bose–Einstein statistics, accounts for the cohesive
streaming of laser light"

Fermi statistics mean that you can't put two electrons in the same state, but
photons want to dogpile into the same state, that's what stimulated emission
is all about.

