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omaha393 writes:
Researchers have addressed a perplexing issue in physics: the existence of time crystals. Time crystals, previously only hypothetical in nature, are structures that oscillate without any external energy supplied. The idea of time crystals set off a massive feud among physicists, arguing that such a state of matter could not exist. As leading time crystal proponent Frank Wilczek describes it: "conceptually, it is a clock that ticks forever without being wound." With the paper published in Nature Wednesday, researchers showed their method of production and the unusual nature of time crystals, which owe their oscillation properties to never achieving a state of equilibrium. From a report on Phys.org:
Ordinary crystals such as diamonds, quartz or ice are made up of molecules that spontaneously arrange into orderly three-dimensional patterns. The sodium and chlorine atoms in a crystal of salt, for example, are spaced at regular intervals, forming a hexagonal lattice. In time crystals, however, atoms are arranged in patterns not only in space, but also in time. In addition to containing a pattern that repeats in space, time crystals contain a pattern that repeats over time. One way this could happen is that the atoms in the crystal move at a certain rate. Were a time crystal of ice to exist, all of the water molecules would vibrate at an identical frequency. What is more, the molecules would do this without any input from the outside world. [...] Shivaji Sondhi, a Princeton professor of physics said that the work addresses some of the most fundamental questions about the nature of matter. "It was thought that if a system doesn't settle down and come to equilibrium, you couldn't really say that it is in a phase. It is a big deal when you can give a definition of a phase of matter when the matter is not in equilibrium," he said.
Time Crystal == Oscillator?
By pz
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2017-Mar-8 15:21
• Score: 5, Interesting
• Thread
I read the linked article (which is a summary of the real report). It's not my field.
How is what they describe anything other than just a stable oscillator? It consumes energy, since to run it requires regular (although perhaps not periodic?) pulses of light.
How is this different from a macroscopic tuned circuit that also resists changes in driving force, and oscillates at a stable frequency? Because it's made with a handful of atoms instead of gazoober electrons streaming around a circuit? I'm (not intentionally) being snarky -- I'm curious because by the article the physicists are peeing all over themselves in excitement, so I'm guessing they think there's something to this that I don't see.
Conservation of energy
By TWX
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2017-Mar-8 15:28
• Score: 4, Interesting
• Thread
Shouldn't this violate the Law of Conservation of Energy? Or is this literally the achievement of what would have normally been thought of as an asymptote to infinity, where no energy can be extracted from this closed system and it's perpetuating on merely perfect conservation of the energy that was introduced into the system when it was established?
Why is it assumed this is related to Time?
By Vitriol+Angst
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2017-Mar-8 15:30
• Score: 4, Interesting
• Thread
I think it's flawed logic to assume that the lowest energy state in a universes so fluid and in motion would be absolute stillness.
Perhaps it's oscillations due to the quantum foam, or space/time itself moves, and thus a lower energy particle would vibrate at some frequency rather than not.
Cannot be created on Earth --DANGER
By tekrat
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2017-Mar-8 15:55
• Score: 3
• Thread
Or anywhere else in the physical universe, unless some special laws apply. If you create a form of matter that is "stuck" in time, that matter will be locked in a spot in the physical universe.
The problem we will have is that the Earth is spinning, the Earth is going around the Sun, the solar system is swirling within the Milky Way, and the Galaxy exists in a universe that is expanding. Once you remove a physical object from relativity, all hell will break loose. From our perspective, that material will rocket off into space (or burrow right through the planet).
Essentially we will have left it behind, locked in the space-time it was created in.
Re:Time Crystal == Oscillator?
By TooManyNames
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2017-Mar-8 16:24
• Score: 4, Interesting
• Thread
It's different from a macroscopic tuned circuit in that the driving energy is decoupled from the resulting oscillations. Basically, some energy is indeed required to maintain the crystalline (repeating pattern) structure in time, but that pattern is precise and does not depend on the energy supplied. In a typical oscillating circuit, on the other hand, you would indeed see recurring oscillations for a given supply voltage, for example, but if you vary that voltage, the oscillations settle to a quite significantly different frequency.
This isn't a perpetual motion machine, but it does exhibit characteristics that are nonetheless really cool and potentially quite useful, and it does so by relying on what is essentially a new matter phase previously though to be impossible.