mc ☕ @mc@qoto.org
Describe myself in 5 tag words:
#mathfolk #programmer #reader #traveller #researcher
header: Cobalt Mirror (Lake Louise), photo by Paul Zizka
> Since Pines' Demon is predicted to play an important role in a wide range of phenomena, such as #transitions in particular kinds of #semimetals and #superconductivity , the work has important implications for material #physics .
> Usually in science, a "demon" is a hypothetical opponent for scientists and philosophers to argue against in a thought experiment, but Pines' Demon is quite different.
It's actually a type of #plasmon – a discrete unit of waves among rippling through a population of electrons . Plasmons have been described as the #quantum analogue of an #acoustic sound in a classical gas.
#Physicists Have Observed a 'Demon' Plasmon in Strontium Ruthenate
https://www.sciencealert.com/physicists-have-observed-a-demon-plasmon-in-strontium-ruthenate
> One of the key insights of #quantummechanics is that absolute #nothingness, a concept already discussed by Greek philosophers, is nowhere to be found in reality. Quite to the contrary, #QuantumFieldTheory has shown that seemingly empty space is filled by #fluctuations of #light and #matter fields, leading to a continuous #popping into existence and disappearance of #photons as well as massive #particles. In the founding days of quantum mechanics, these consequences of Heisenberg's uncertainty principle were often not taken too seriously. However, modern physics is increasingly discovering how our universe is shaped by fluctuations of physical fields, which not only lead to tiny shifts of spectral lines of atoms, but moreover may cause the evaporation of black holes, and are ultimately responsible for the large-scale #structure of our #universe, formed during the inflationary period following the big bang.
Understanding #vacuum fluctuations in #space
https://phys.org/news/2020-08-vacuum-fluctuations-space.html
> On October 4th Alain Aspect, John Clauser and Anton Zeilinger were awarded the #Nobel #Prize in physics for proving that the #Universe isn't #locally #real .
What I love about this story is that it's a story of quite literally some of the smartest people who have ever lived being confused and how ultimately #Einstein was #proven #wrong , which doesn't really happen all that often.
That idea of #locallyreal is made up of two concepts:
#Locality is the idea that things are only affected by their local environment - you can't flick a switch in another galaxy hundreds of light years away and instantly see the results here because nothing not even information can travel faster than light.
#Realness though is much harder to explain and that is the focus of the #NobelPrize . ...
How #Physicists Proved The Universe Isn't Locally Real - Nobel Prize in #Physics 2022 EXPLAINED
https://www.youtube.com/watch?v=txlCvCSefYQ
> One of the central problems in fluid dynamics is to figure out if the [Euler] equations ever fail, outputting nonsensical values that render them unable to predict a fluid’s future states.
> Mathematicians have long suspected that there exist initial conditions that cause the equations to break down. But they haven’t been able to prove it.
> In a preprint posted online last month, a pair of mathematicians has shown that a particular version of the Euler equations does indeed sometimes fail.
...
> Perhaps in some situations, the equations will proceed as expected, producing precise values for the state of the fluid at any given moment, only for one of those values to suddenly skyrocket to infinity. At that point, the Euler equations are said to give rise to a “singularity” — or, more dramatically, to “blow up.”
> Once they hit that singularity, the equations will no longer be able to compute the fluid’s flow.
...
Computer Proof ‘Blows Up’ Centuries-Old Fluid Equations
https://www.quantamagazine.org/computer-helps-prove-long-sought-fluid-equation-singularity-20221116/
Very important and interesting work, if you're a mathematician, a physicist or an engineer that has ever 'crashed' with Euler/Navier-Stokes equations.
#math #physics #fluids #euler #navierstokes #equations #singularities
surprising #connections between #Number_Theory and #physics
number theory and physics archive
http://empslocal.ex.ac.uk/people/staff/mrwatkin/zeta/physics.htm
> space—and perhaps even time—is not fundamental. Instead #space and #time may be emergent: they could arise from the structure and behavior of more basic components of nature.
> best theory of #gravity is general #relativity , Albert Einstein’s famous conception of how matter warps space and time
> best #theory_o_everything else is #quantum #physics
> But the two theories don’t play nicely
> Nature knows how to apply gravity in quantum contexts—it happened in the first moments of the #big_bang, and it still happens in the hearts of #black_holes —but we humans are still struggling to understand how the trick is done.
> quantum physics treats space and time as immutable, general relativity warps them
> If #spacetime is #emergent, then figuring out where it comes from—and how it could arise from anything else—may just be the missing key that finally unlocks the door to a theory of everything.
> uncovered a duality between a kind of well-understood quantum theory known as a conformal field theory (CFT) and a special kind of spacetime from general relativity known as anti–de Sitter space (AdS).
> The two seem to be wildly different theories—the CFT has no gravity in it whatsoever, and the AdS space has all of Einstein’s theory of gravity thrown in. Yet the same mathematics can describe both worlds.
> Based on some of the peculiar characteristics of black holes, ’t Hooft and Susskind suspected that the properties of a region of space might be fully “encoded” by its boundary.
> in the AdS/CFT correspondence, the four-dimensional CFT encodes everything about the five-dimensional AdS space it is associated with. In this system, the entire region of spacetime is built out of interactions between the components of the quantum system in the conformal field theory.
> If this space is emergent, what is it emerging from? The answer is a special and strangely quantum kind of interaction in the CFT: #entanglement, a long-distance #connection between objects, instantaneously correlating their behavior
> entanglement is what produces distances in the AdS space in the first place. Any two nearby regions of space on the AdS side of the duality correspond to two highly #entangled quantum components of the CFT.
> this relation might apply to our universe as well.
> “What is it that holds the space together and keeps it from falling apart into separate subregions? The answer is the entanglement
> space itself emerges out of a fundamentally quantum phenomenon
... and this is only the skeleton of 1 of 2 new theories that intend to explain space (and probably time) as emergent. If you're on these matters you must read the article in full.
What Is Spacetime Really Made Of?
https://www.scientificamerican.com/article/what-is-spacetime-really-made-of/
> "Instead of computation, we're putting the computer to work as a new experimental platform to realize and detect new phases of matter."
> "Time-crystals are a striking example of a new type of non-equilibrium quantum phase of matter," says Khemani.
"While much of our understanding of condensed matter physics is based on equilibrium systems, these new quantum devices are providing us a fascinating window into new non-equilibrium regimes in many-body physics."
Modelling their time crystal on Google's quantum technology allowed the team to look for signs of infinite repetition within just a few hundred kicks of a laser pulse. They could also run the simulation backwards and scale its size.
https://www.sciencealert.com/physicists-used-a-quantum-computer-t o-show-their-time-crystal-design-is-the-real-deal
"...
What defines any bog-standard crystal—such as a diamond, an emerald, or even an ice cube—is that the crystal’s atoms are somehow arranged in repeating patterns in space. There’s three dimensions of space—and a fourth dimension, time. So physicists wondered if a crystal’s atoms could be arranged in repeating patterns in time.
In practice, that works something like this. You create a crystal whose atoms start in one state. If you blast that crystal with a finely tuned laser, those atoms might flip into another state—and then flip back—and then flip again—and so forth, all without actually absorbing any energy from the laser.
If you step back, what you’ve just created is a state of matter that’s perpetually in motion, indefinitely, without taking in any energy.
That’s no small feat. It beats against one of classical physics’ most sacred tenets: the second law of thermodynamics. ..."
#physics #time #entropy #quantum #computing #math
https://www.popsci.com/science/what-is-time-crystal-physics/
So You Want to #Learn #Physics…
an #outline by Susan Rigetti
https://www.susanrigetti.com/physics
Note: This reminded me how important is for the TAs to have a good bibliography list for every course.
Hi,
I'm #newhere . I'm interested in #math #physics #astronomy #programming #books #music #films
Describe myself in 5 tag words:
#mathfolk #programmer #reader #traveller #researcher
header: Cobalt Mirror (Lake Louise), photo by Paul Zizka
