First suggested by Nobel-Prize winning theoretical physicist Frank Wilczek in the year 2012, time crystals are hypothetical arrangements that seem to have movement even at their lowest energy state. This capability breaks a fundamental symmetry in physics known as time-translation symmetry (TTS), but physicists have now confirmed that it might, in fact, be possible for time crystals to substantially exist. If you have no idea about what we are talking, do not worry, we will run you through the backstory.
In the year 2012, Wilczek and a group of theoretical physicists at MIT proposed that it could be possible to add a fourth dimension, the crusade of time - to a crystal, infusing it with the ability to act as a kind of continuous 'time-keeper', or clock. In simple terms, Frank Wilczek proposed an object that could attain endless movement by periodically moving and then returning to its initial state over and over again in its lowest-energy state, called ground state.
As Bob Yirka describes for Phys.org, Wilczek Frank suggested that it could be possible to build a time crystal using a low-temperature super-conductor, because crystals naturally support themselves at low temperatures.
Bob Yirka says, "It appeared reasonable to undertake that the atoms in such a crystal could possibly move or rotate and then return to their natural state naturally, repeatedly, as crystals are won’t to as they find the lowest energy state."
The idea was that a circle of ions inside the crystal could be prepared to move freely inside the crystal, like a mouse discovering the inside of a snake's stomach, but he could not figure out how to construct such a thing. In months, another group of physicists from Purdue University jumped in and said Frank Wilczek’s idea could work, they just required better ion traps, which was something that would possibly be developed in the next few years. Fast forward to now and those estimates are looking pretty perfect.
Physicists from the University of California, Santa Barbara have suggested that it is possible, in theory, to form a time crystal from a large structure of trapped atoms, ions, or super-conducting qubits, particles used in quantum computers to switch the bits of today’s computers, just as the Purdue team had expected four years ago. But they were not searching for a method to create a time crystal, definitely. They were much more interested in trying to demonstrate that time crystals could exist by undertaking the biggest argument contrary to them, that their existence basically breaks time-translation symmetry (TTS).
Time-translation symmetry is a type of one of the three symmetries of space-time known as translation symmetry; it states that the laws of physics are the same in all the places and at all the times. It is the utmost fundamental suppositions of our present understanding of physics, but the University of California team debates that you can really break time-translation symmetry without taking everything you know.
As Zyga describes, although spontaneously broken time-translation symmetry has never been detected before, nearly every other kind of spontaneous symmetry breaking has been, for instance, how magnets acquire their both poles, what force decided which would be north and which would be south? and how familiar crystals look different when observed from different angles in space. Using a recreation, the team revealed how suddenly broken time-translation symmetry could happen in a type of quantum system called 'Floquet-many-body-localized driven structures (or systems)'.
They discovered that a humble crystal could become such a system, and could be talented to attain two things that allowed it and our present understanding of physics to co-exist. First, it continued far from thermal equilibrium at all times, meaning the structure not once heated up, even with its periodic, oscillating movements.
And secondly, as the size of the system remained growing, the time it acquired for a symmetry-breaking state to revert into symmetry-respecting state increased, meaning that in an infinite system, the symmetry-respecting state can never be approached.
So time-translation symmetry can be destroyed indefinitely inside the time crystal system, but this forever rotating object does not heat up, so the second law of thermodynamics remains unbroken, a crucial condition for a time crystal to exist inside the laws of physics.
Bela Bauer, a member of the scientist’s team, told Phys.org, "The importance of our work is two-fold: on one hand, it proves that time-translation symmetry is not resistant to being spontaneously broken. On the other hand, it expands our understanding that non-equilibrium systems can host numerous interesting states of matter that can’t exist in equilibrium systems."
The next step, obviously, is for someone to go forward and build such object for real. And with this proof in place, there’s never been a better time to shape out a time crystal.