‘Milestone’ Evidence for Anyons, a Third Kingdom of Particles
https://www.quantamagazine.org/milestone...-20200512/
INTRO: Every last particle in the universe — from a cosmic ray to a quark — is either a fermion or a boson. These categories divide the building blocks of nature into two distinct kingdoms. Now researchers have discovered the first examples of a third particle kingdom. Anyons, as they’re known, don’t behave like either fermions or bosons; instead, their behavior is somewhere in the middle. In a recent paper published in Science, physicists have found the first experimental evidence that these particles don’t fit into either kingdom. “We had bosons and fermions, and now we’ve got this third kingdom,” said Frank Wilczek, a Nobel prize–winning physicist at the Massachusetts Institute of Technology. “It’s absolutely a milestone.” (MORE)
The unexpected reason why the smallest black holes bend space the most
https://www.forbes.com/sites/startswitha...45c862275c
EXCERPT: . . . But there are a few properties that aren't comparable for black holes of different masses. Tidal forces, for example, are a case where the differences are enormous. [...] Perhaps the most striking difference between black holes of different masses, however, comes about from a phenomenon we've never actually observed: Hawking radiation. Wherever you have a black hole, you have a very small amount of low-energy radiation being emitted from it.
Although we've concocted some very pretty visualizations of what causes it — we typically talk about the spontaneous creation of particle-antiparticle pairs where one falls into the black hole and one escapes — that's not what's really going on. It is true that radiation is escaping from the black hole, and it's also true that the energy from that radiation has to come from the mass of the black hole itself. But this naive picture of particle-antiparticle pairs popping into existence and one member escaping is grossly oversimplified.
The real story is a little more complicated, but vastly more illuminating. Wherever you have space itself, you also have the laws of physics that exist in our Universe, which includes all the quantum fields that underlie reality. These fields all exist in their lowest-energy state when they permeate empty space, a state known as "the quantum vacuum."
The quantum vacuum is the same for everyone so long as they're in empty, uncurved space. But that lowest-energy state is different in places where the spatial curvature is different, and that's where Hawking Radiation actually comes from: from the physics of quantum field theory in curved space. Far enough away from anything, even a black hole, the quantum vacuum looks like it does in flat space. But the quantum vacuum differs in curved space, and differs more dramatically where space is more severely curved.
That means, if we want the brightest, most luminous, most energetic Hawking radiation to come from our black hole, we'd want to go to the lowest-mass black holes we can find: the ones where the spatial curvature at their event horizon is the strongest. If we were to compare a black hole like the one at the center of M87 with the imaginary one we'd have if the Sun became a black hole, we'd find:
• the more massive black hole has a temperature that's billions of times lower,
• has a luminosity that's ~20 orders of magnitude lower,
• and will evaporate on timescales that are ~30 orders of magnitude longer.
This means that it's the lowest-mass black holes of all that are the locations where space is the most strongly-curved out of all the places in the Universe, and — in many ways — make for the most sensitive natural laboratory to test the limits of Einstein's General Relativity.
It might seem counterintuitive to think that the lowest-mass black holes in the Universe curve space more severely than the supermassive behemoths that populate the centers of galaxies, but it's true. Curved space isn't just about how much mass you have all in one place, because what you can observe is limited by the presence of an event horizon. The smallest event horizons are found around the lowest-mass black holes. For metrics like tidal forces or black hole decay, being close to the central singularity is even more important than your overall mass... (MORE - details)
https://www.quantamagazine.org/milestone...-20200512/
INTRO: Every last particle in the universe — from a cosmic ray to a quark — is either a fermion or a boson. These categories divide the building blocks of nature into two distinct kingdoms. Now researchers have discovered the first examples of a third particle kingdom. Anyons, as they’re known, don’t behave like either fermions or bosons; instead, their behavior is somewhere in the middle. In a recent paper published in Science, physicists have found the first experimental evidence that these particles don’t fit into either kingdom. “We had bosons and fermions, and now we’ve got this third kingdom,” said Frank Wilczek, a Nobel prize–winning physicist at the Massachusetts Institute of Technology. “It’s absolutely a milestone.” (MORE)
The unexpected reason why the smallest black holes bend space the most
https://www.forbes.com/sites/startswitha...45c862275c
EXCERPT: . . . But there are a few properties that aren't comparable for black holes of different masses. Tidal forces, for example, are a case where the differences are enormous. [...] Perhaps the most striking difference between black holes of different masses, however, comes about from a phenomenon we've never actually observed: Hawking radiation. Wherever you have a black hole, you have a very small amount of low-energy radiation being emitted from it.
Although we've concocted some very pretty visualizations of what causes it — we typically talk about the spontaneous creation of particle-antiparticle pairs where one falls into the black hole and one escapes — that's not what's really going on. It is true that radiation is escaping from the black hole, and it's also true that the energy from that radiation has to come from the mass of the black hole itself. But this naive picture of particle-antiparticle pairs popping into existence and one member escaping is grossly oversimplified.
The real story is a little more complicated, but vastly more illuminating. Wherever you have space itself, you also have the laws of physics that exist in our Universe, which includes all the quantum fields that underlie reality. These fields all exist in their lowest-energy state when they permeate empty space, a state known as "the quantum vacuum."
The quantum vacuum is the same for everyone so long as they're in empty, uncurved space. But that lowest-energy state is different in places where the spatial curvature is different, and that's where Hawking Radiation actually comes from: from the physics of quantum field theory in curved space. Far enough away from anything, even a black hole, the quantum vacuum looks like it does in flat space. But the quantum vacuum differs in curved space, and differs more dramatically where space is more severely curved.
That means, if we want the brightest, most luminous, most energetic Hawking radiation to come from our black hole, we'd want to go to the lowest-mass black holes we can find: the ones where the spatial curvature at their event horizon is the strongest. If we were to compare a black hole like the one at the center of M87 with the imaginary one we'd have if the Sun became a black hole, we'd find:
• the more massive black hole has a temperature that's billions of times lower,
• has a luminosity that's ~20 orders of magnitude lower,
• and will evaporate on timescales that are ~30 orders of magnitude longer.
This means that it's the lowest-mass black holes of all that are the locations where space is the most strongly-curved out of all the places in the Universe, and — in many ways — make for the most sensitive natural laboratory to test the limits of Einstein's General Relativity.
It might seem counterintuitive to think that the lowest-mass black holes in the Universe curve space more severely than the supermassive behemoths that populate the centers of galaxies, but it's true. Curved space isn't just about how much mass you have all in one place, because what you can observe is limited by the presence of an event horizon. The smallest event horizons are found around the lowest-mass black holes. For metrics like tidal forces or black hole decay, being close to the central singularity is even more important than your overall mass... (MORE - details)