The connection of two “time crystals” in a superfluid of helium-3 barely one ten thousandth of a degree above absolute zero can be a big step towards a new type of quantum computer.
Time crystals are bizarre structures of atoms, whose existence was only predicted as late as 2012, with experimental evidence a few years later. In a normal crystal, such as diamond or salt, the atoms are arranged in a regularly repeating space pattern – a lattice or similar framework. And like most materials, when the atoms are in their basic state – their lowest possible energy level – they stop wobbling.
Time crystals, on the other hand, consist of atoms that repeat themselves in time rather than in space, swing back and forth, or spin, even in their basic state. They can maintain this movement constantly, without having to add energy or lose energy in the process.
By doing so, these time crystals can defy a concept called entropy. The second law of thermodynamics describes entropy as how any system becomes more disordered over time. As an example, consider the orbits of the planets around Solar. For the sake of simplicity, we imagine that they move in clockwise order and always return to the same place at the same time in their respective paths. In reality, though, it’s messy: The seriousness of the other planets, or passing stars, can drag and pull in the planets and make subtle changes in their orbits.
Hence the orbits of the planets is chaotic in nature. A small change of one can potentially have major repercussions for all of them. The system becomes disordered over time – the entropy of the system increases.
Time crystals can cancel out the effects of entropy due to a quantum mechanical principle known as “the location of many objects.” If a force is felt by an atom in the time crystal, it only affects that atom. Therefore, the change is considered to be local rather than global (throughout the system). As a result, the system does not become chaotic and allows the repeated oscillations to continue, theoretically, forever.
“Everyone knows that eternity machines are impossible,” said Samuli Autti, a researcher and lecturer in physics at Lancaster University in the UK. statement. “But in quantum physics, perpetual motion is okay as long as we keep our eyes closed.”
Autti, who led the research, refers to Heisenberg’s uncertainty principle, which alludes to how, when a quantum system is observed and measured, its quantum wave function collapses. Due to their quantum mechanical nature, time crystals can work with 100% efficiency only when they are completely isolated from their environment. This requirement limits how long they can be observed until they are completely degraded as a result of wave function collapse.
But Autti’s team managed to connect two time crystals by cooling a lot helium-3, an isotope of helium. Helium-3 is special because the isotope becomes a superfluid, which not many materials can do when cooled to a fraction above absolute zero (minus 459.67 degrees Fahrenheit or minus 273 degrees Celsius). In a superfluid, there is zero viscosity, so no kinetic energy is lost through friction, which means that movements – like the atoms in a time crystal – can continue indefinitely.
Autti’s team, working at Aalto University in Finland, then manipulated the helium-3 atoms to create two time crystals that interacted with each other. In addition, they observed this time crystal pairing for a record time, about 1,000 seconds (almost 17 minutes), which corresponds to billions of periods of oscillating or spinning motions of the atoms, before the wave function of the time crystals slowed down.
“It turns out that putting two of them together works beautifully,” Autti said.
The results create a promising line of research to develop a fully functioning quantum computer. While the bits in a normal computer are binary – 1s or 0s, on or off – the processing speed of quantum computers are much faster because they use “qubits”, which can be 1 and 0, on and off at the same time. One way to build a quantum computer would be to link together countless time crystals, each designed to act as a qubit. Therefore, this first experiment to link two time crystals has created the basic building block of a quantum computer.
Previous experiments have already shown that crystals can work at room temperature for a while, rather than having to be cooled to almost absolute zero, which makes their construction even easier. The next task, said Autti’s team, is to show that logical gate operations, which are functions that allow a computer to process information, can work between two or more time crystals.
The research was published on June 2 in the journal Nature communication (opens in new tab).
#Time #crystals #work #laws #physics #offer #era #quantum #computation