(ORDO NEWS) — Physicists have just taken a surprising step towards quantum devices that sound like something out of science fiction.
For the first time, isolated groups of particles have been discovered that behave like bizarre states of matter known as time crystals. linked into a single evolving system that could be incredibly useful in quantum computing.
After first observing the interaction between two time crystals, detailed in an article two years ago, this is the next step towards potentially using time crystals for practical purposes such as quantum information processing.
Time crystals, officially discovered and confirmed only a few years ago in 2016, were once thought to be physically impossible. This is a phase of matter, very similar to normal crystals, but with one additional, peculiar and very special property.
In ordinary crystals, the atoms are arranged in a fixed three-dimensional network structure, similar to the atomic lattice of a diamond or quartz crystal. These repeating grids may vary in configuration, but any movement they exhibit is solely from external shocks.
In time crystals, atoms behave somewhat differently. They demonstrate patterns of movement in time that cannot be so easily explained by an external push or push. These oscillations, called “ticks”, are tied to a regular and specific frequency.
Theoretically, time crystals tick in the lowest possible energy state, known as the ground state, and are therefore stable and coherent. over long periods of time. So, where the structure of regular crystals is repeated in space, in time crystals it is repeated in space and time, thus demonstrating perpetual motion in the ground state.
“Everyone knows that perpetual motion machines are impossible,” says physicist and lead author Samuli Autti of Lancaster University in the UK.
“However, in quantum physics, perpetual motion is allowed as long as we keep our eyes closed. By sneaking into this crack, we can create time crystals.”
The time crystals the team worked with are made up of quasi-particles called magnons. Magnons are not true particles, but consist of a collective excitation of the spin of electrons, like a wave that propagates through a lattice of spins.
Magnons are created when helium-3 a stable isotope of helium with two protons and only one neutron is cooled to within one ten-thousandth of a degree of absolute zero. This creates what is known as B-phase superfluidity, a liquid with zero viscosity and low pressure.
In this environment, the time crystals formed as spatially distinct Bose-Einstein condensates, each consisting of a trillion magnon quasi-particles.
A Bose-Einstein condensate is formed from bosons cooled just above absolute zero (but not reaching absolute zero, after which the atoms stop moving).
This causes them to sink into their lowest energy state, moving extremely slowly and coming close enough to overlap, forming a high density cloud of atoms that acts as a single “superatom” or wave of matter.
When two times the crystals were allowed to touch each other, they exchanged magnons. This exchange affected the fluctuation of each of the time crystals, creating a single system with the ability to function in two discrete states.
In quantum physics, objects that can have more than one state exist in a mixture of these states before they are captured by a precise measurement. Thus, having a time crystal operating in a two-state system opens up rich new possibilities as a basis for quantum technologies.
Time crystals are a good way to go from being deployed as qubits as there are a significant number of hurdles to overcome first. But everything falls into place.
Earlier this year, another group of physicists announced the successful creation of room-temperature time crystals that do not need to be isolated from the environment.
Further development of more complex interactions between time crystals and their precise control will be required, as well as observations of interacting time crystals without the need for cooled superfluids. But scientists are optimistic.
“It turns out that pairing the two of them works great, even if the time crystals aren’t supposed to exist at all,” says Autty. “And we already know they exist at room temperature as well.”
Contact us: [email protected]