He and Shapere showed that a material could have zero total energy yet still be in motion. They did so by mathematically reformulating the ordinary definition of kinetic energy (one-half mass times velocity squared) to a different but equally valid value that depends on a velocity in an alternative way (for instance, adding an additional term such as velocity to the fourth power and changing the sign of the usual kinetic energy).
"I'm just very surprised at this," says theoretical physicist Maulik Parikh of Arizona. "Frank found subtle exceptions that link motion and the state of being at minimum energy."
Carroll agrees: "It's amusing to find a system that features motion in its ground state, but it certainly doesn't violate any truly cherished beliefs of physics. I'm ready to believe that such a system could even be constructed in the real world."
The motion of the crystal "'spontaneously breaks' time translation symmetry, even if the theory itself does not contain any preferred time direction," says Cristian Armendáriz Picón of Syracuse University, who has studied the possibility of similar phenomena in cosmology.
Once set in motion, a time crystal could remain in motion forever, with no outside force needed to keep it going. This type of perpetual motion machine would not violate any known physical law because no energy could be extracted from the system without first adding energy. Such systems might even be arranged to convey information that would persist after everything else around them has died.
Carroll cautions, however, that a time crystal may not survive indefinitely. Even if the crystal has the minimum possible energy, it might not have the highest possible entropy, or disorder; a crystal blown up into individual particles and spread across space would have higher entropy. If so, the time crystal would eventually suffer such a fate, because the universe always evolves toward higher entropy. "I don't think it's realistic to expect such a thing to last literally forever—but much longer than anything else is quite conceivable," Carroll says.
The closest that modern technology has come to a time crystal, Wilczek says, is a current-carrying superconductor, a material that carries a moving, persistent current at low temperatures. In an ordinary superconducting cable, the current is constant, and if nothing actually changes with time, the superconductor does not qualify as a true crystal. But if engineers could construct a superconductor with a lumpy rather than uniform distribution of charged particles, then as the current flows, the lumps move, and the persistent current would change with time.
The concept of a time crystal, Armendáriz Picón says, may shed light on how natural phenomena that are asymmetric with time can be described in terms of symmetric theories. It could even apply to the origin and evolution of the universe. "One can think of these [time] crystals as a new form of matter, and this matter may be responsible for ill-understood phenomena such as the current stage of accelerated cosmic expansion," he says.
"It's early days" for the theory, Wilczek cautions. For physicists, time crystals are "like discovering a new continent," he said in a recent talk. But, he adds, whether that new continent is "a New World, or Antarctica, time will tell."
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16 Comments
Add CommentIMO every wave is such a time crystal
Reply | Report Abuse | Link to thisThis might help explain the origin of a big bang. You take a universe of nothing. It needs an energy imparted to make it change to something but where do you get that energy, the energy imparted by time. This may even help with looking at Black holes maybe we can rename them time holes since even light apparently stops in a black hole how it's converted back into time. Crazy I know but I like it and it fits some of my theories.
Reply | Report Abuse | Link to thisI remember when I was in 7th grade and first heard about black holes,I thought to myself that a singalarity in the hole was frozen in time and thus having a fixed mass,all other mass of a black hole was frozen at the event horizen.When t=o all wave function ceases and everything else all the way to the bottom is frozen as well.The black hole as whole may be spinning but everything inside is motionless.Kinda like the time crystal mentioned in the article,but alas I was called an moron by the teacher,and my theroy was not to be spoken again.Sorry about the spelling,I no longer have a working spellchecker.
Reply | Report Abuse | Link to thisI remember when I was in 7th grade and first heard about black holes,I thought to myself that a singalarity in the hole was frozen in time and thus having a fixed mass,all other mass of a black hole was frozen at the event horizen.When t=o all wave function ceases and everything else all the way to the bottom is frozen as well.The black hole as whole may be spinning but everything inside is motionless.Kinda like the time crystal mentioned in the article,but alas I was called an moron by the teacher,and my theroy was not to be spoken again.Sorry about the spelling,I no longer have a working spellchecker.
Reply | Report Abuse | Link to thisMatter in motion creates 3D space and past-to-future time. Neither 3D space nor past-to-future time exist without matter in motion.
Reply | Report Abuse | Link to thisNo, we can't get anything for free. Notice where it says that now energy can be extracted from this system without first adding the same amount in. What goes in is the most that can come out. This is not getting anything for free, just keeping what we got for a long time.
Reply | Report Abuse | Link to thisWith With all due respect, Prof. Wilczek, Prof. Shapere, and the rest of us here, might appreciate that crystals, like all other forms of matter, or mass-energy, consist basically of atoms- which are the true perpetual-motion machines in our universe. The vibrant and ever-breathing atom - even in its ground (unexcited) state - breathes in mass-energy [currently termed a a virtual particle, flitting out of the void (and into the atom)] and breathes out an ethe quantum over the following half-cycle of exhalation [virtual particle flitting (out from the atom and) into the outside void]. And the sooner we realize this most fundamental fact of natuure, the sooner will 'modern physics' emerge from the woods, for the complete unification of physics and the advancement of science. Get the picture in:
Reply | Report Abuse | Link to thishttp://www.sittampalam.net/MassEnergy.htm and
http://www.sittampalam.net/TheSpin.htm
With all due respect, Prof. Wilczek, Prof. Shapere, and the rest of us here, might appreciate that crystals, like all other forms of matter, or mass-energy, consist basically of atoms- which are the true perpetual-motion machines in our universe. The vibrant and ever-breathing atom - even in its ground (unexcited) state - breathes in mass-energy [currently termed a a virtual particle, flitting out of the void (and into the atom)] and breathes out an equal quantum over the following half-cycle of exhalation [virtual particle flitting (out from the atom and) into the outside void]. And the sooner we realize this most fundamental fact of natuure, the sooner will 'modern physics' emerge from the woods, for the complete unification of physics and for the advancement of science. Get the picture in:
Reply | Report Abuse | Link to thishttp://www.sittampalam.net/MassEnergy.htm and
http://www.sittampalam.net/TheSpin.htm
(Please use Internet Explorer if possible.)
Thank you all for your time here. Cheers!
The article prompts two thoughts. First, let's simplify the picture of our universe, without changing its laws of physics. Assume the universe consists of a single hydrogen atom at N degrees K. Overtime, the atom cools, throwing off photons to carry off the vibrational energy -- conserving the energy of the system, and increasing its entropy. Ultimately the atom stops vibrating completely (except for the occasional jolt it might get if one if its photons happens to bumo into it). Thus the energy of the universe is concerved, but the universe itself, is (thereby) a perpetual motion machine (albiet, one from which no energy can be extracted). Interesting to think of what this means for multiverse theories in which universes can interact (colliding branes, et al).
Reply | Report Abuse | Link to thisThought 2 is a quesiton ("Quesiton" was invented as a typo, but I have since defined it as the smallest unit of something you want to know): What accounts for the energy required for the electron to keep spinning around the proton in my hydrogen atom -- or any other atoms, for that matter?
Even though the electron appears to orbit an nucleus, it's not really an orbit like the moon orbiting the Earth. The orbit analog of electrons is a useful first order approximation but falls short of complete fidelity. The orbit of an electron(s) is a probabilistic state bounded within energy "shells" define by the Pauli exclusion principal. If you observed the moon an hour ago, and then again now, you could be very certain of the whereabouts of the moon in the between time. Not so with an electron.
Reply | Report Abuse | Link to thiswhoops - Pauli exclusion principle...not principal.
Reply | Report Abuse | Link to thisUnderstood about the "orbits." My question is about the movement of the electrons, and where the energy comes from that motion. Or are you saying that there is not real motion, as such, just that there is only probability about where the electrons are (so they might as well be moving)... and a degree of interaction potential?
Reply | Report Abuse | Link to thisIs it possible, in considering your 7th grade hypothesis, that; "I no longer have a working spellchecker." Kinda closes the discussion?
Reply | Report Abuse | Link to thisThe Black Hole thing is interesting. But the second clause is disturbing.
Mr. Markcomman, if I may kindly comment here on your above thoughts,the atom is an ever-vibrant entity and, therefore, cannot simply cool itself by breathing (throwing) off photons; the atomic vibration itself is the direct cause of this breathing, which would conserve entropy over a cycle of breathing at steady state. Please note that the the atom cannot ever stop vibrating (which can occur only at the unreachable absolute temperature of zero Kelvin).
Reply | Report Abuse | Link to thisFurther, in this fractal universe of ours, the electron's orbit around the atomic nucleus is but the submicroscopic image of the planetary orbit around the sun (or central star). A quick glimpse of the following, illustrative website should bring to light this great recurring design element in nature.
http://www.sittampalam.net/AntiGravity.htm
Reuuest for any further clarifications is most welcome. Thank you, and Cheers all!
http://toe.tv
Maybe someone should tell Wilczek about real perpetual motion systems, which have been studied in the laboratory for many years, viz. superconductors? There's too much specialisation in physics these days!
Reply | Report Abuse | Link to thisFor completeness, it should be added that in the two superconductor case there is time dependence as well as perpetual motion (the phase difference is a function of time). When you connect the two there is an ac supercurrent which is a reflection of that time dependence. If you do this you'll get dissipation, but that will happen in any periodic system once you try to _observe_ the oscillations.
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