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Two researchers at Harvard University, Aavishkar A. Patel and Subir Sachdev, have recently presented a new theory of a Planckian metal that could shed light on previously unknown aspects of quantum physics. Their paper, published in Physical Review Letters, introduces a lattice model of fermions that describes a Planckian metal at low temperatures (Tà 0).
Metals contain numerous electrons, which carry electric current. When physicists consider the electrical resistance of metals, they generally perceive it as arising when the flow of current-carrying electrons is interrupted or degraded due to electrons scattering off impurities or off the crystal lattice in the metal.
“This picture, put forth by Drude in 1900, gives an equation for the electrical resistance in terms of how much time electrons spend moving freely between successive collisions,” Patel told Phys.org. “The length of this time interval between collisions, called the ‘relaxation time,’ or ‘electron liftetime,’ is typically long enough in most common metals for the electrons to be defined as distinct, mobile objects to a microscopic observer, and the Drude picture works remarkably well.”
Idk how I found this o.o
Last year we looked at multiverse theory and the highly speculative — but very real — science behind what has become a pop culture phenomenon. It isn’t just “Stranger Things” anymore. Interdimensional travel, and the portals that might allow it, are everywhere these days.
So, how to open a portal to another dimension?
Continue reading “Do Doors to Interdimensional Travel Exist?” »
One of the all-time great mysteries in physics is why our universe contains more matter than antimatter, which is the equivalent of matter but with the opposite charge. To tackle this question, our international team of researchers have managed to create a plasma of equal amounts of matter and antimatter – a condition we think made up the early universe.
Matter as we know it appears in four different states: solid, liquid, gas, and plasma, which is a really hot gas where the atoms have been stripped of their electrons. However, there is also a fifth, exotic state: a matter-antimatter plasma, in which there is complete symmetry between negative particles (electrons) and positive particles (positrons).
This peculiar state of matter is believed to be present in the atmosphere of extreme astrophysical objects, such as black holes and pulsars. It is also thought to have been the fundamental constituent of the universe in its infancy, in particular during the Leptonic era, starting approximately one second after the Big Bang.
By Rachel Courtland
The crust of neutron stars is 10 billion times stronger than steel, according to new simulations. That makes the surface of these ultra-dense stars tough enough to support long-lived bulges that could produce gravitational waves detectable by experiments on Earth.
Neutron stars are the cores left behind when relatively massive stars explode in supernovae. They are incredibly dense, packing about as much mass as the sun into a sphere just 20 kilometres or so across, and some rotate hundreds of times per second.
The Universe is expanding, and that expansion is speeding up over time. These two facts have been well established through observation, but we don’t know what’s causing that expansion. It seems to be some mysterious, unknown energy that acts like the opposite of gravity.
We call this hypothetical energy “dark energy”, and it’s been calculated to constitute around 72 percent of all the stuff that makes up the Universe. We don’t know what it actually is. But a new experiment has just allowed us to rule out one more thing that it isn’t: a new force.
“This experiment, connecting atomic physics and cosmology, has allowed us to rule out a wide class of models that have been proposed to explain the nature of dark energy, and will enable us to constrain many more dark energy models,’‘said physicist Ed Copeland of the University of Nottingham.
Vast interstellar events where clouds of charged matter hurtle into each other and spew out high-energy particles have now been reproduced in the lab with high fidelity. The work, by MIT researchers and an international team of colleagues, should help resolve longstanding disputes over exactly what takes place in these gigantic shocks.
Many of the largest-scale events, such as the expanding bubble of matter hurtling outward from a supernova, involve a phenomenon called collisionless shock. In these interactions, the clouds of gas or plasma are so rarefied that most of the particles involved actually miss each other, but they nevertheless interact electromagnetically or in other ways to produces visible shock waves and filaments. These high-energy events have so far been difficult to reproduce under laboratory conditions that mirror those in an astrophysical setting, leading to disagreements among physicists as to the mechanisms at work in these astrophysical phenomena.
Now, the researchers have succeeded in reproducing critical conditions of these collisionless shocks in the laboratory, allowing for detailed study of the processes taking place within these giant cosmic smashups. The new findings are described in the journal Physical Review Letters, in a paper by MIT Plasma Science and Fusion Center Senior Research Scientist Chikang Li, five others at MIT, and 14 others around the world.
In the same decade when gravitational waves and a neutron star merger have been observed, astronomers have now observed what they believe to be the first detection of a black hole swallowing a neutron star.
Last Wednesday, gravitational wave detectors in Italy and the US, called LIGO and Virgo, detected telltale ripples in space and time, traced to an event that happened 8,550 million trillion kilometers away from Earth.
Astronomers are analyzing the data from the detection to confirm the size of the two objects that came together to form such cataclysmic ripples, but the event is likely a black hole eating a neutron star.
Cranmer is a member of ATLAS, one of the two general-purpose experiments that, among other things, co-discovered the Higgs boson at the Large Hadron Collider at CERN. He and other CERN researchers recently published a letter in Nature Physics titled “Open is not enough,” which shares lessons learned about providing open data in high-energy physics. The CERN Open Data Portal, which facilitates public access of datasets from CERN experiments, now contains more than two petabytes of information.
It could be said that astronomy, one of the oldest sciences, was one of the first fields to have open data. The open records of Chinese astronomers from 1054 A.D. allowed astronomer Carlo Otto Lampland to identify the Crab Nebula as the remnant of a supernova in 1921. In 1705 Edward Halley used the previous observations of Johannes Kepler and Petrus Apianus—who did their work before Halley was old enough to use a telescope—to deduce the orbit of his eponymous comet.
In science, making data open means making available, free of charge, the observations or other information collected in a scientific study for the purpose of allowing other researchers to examine it for themselves, either to verify it or to conduct new analyses.
Continue reading “With open data, scientists share their work” »
An experiment in the United Kingdom has failed to find evidence of a particle meant to explain most of the universe’s mass. But the search isn’t over.
When cosmologists observe the way the universe expands, they find that present-day theories of matter can’t explain most of the universe’s energy. They call the unknown energy “dark energy,” and theorists have tried to explain it by proposing undiscovered particles and corresponding fields. Experiments have failed to find evidence of such particles, but in physics, that’s not necessarily a bad thing.
