Researchers working in partnership with Google may have used the tech giant’s quantum computer to create something completely new. Phase of matter — Time crystal.
Time crystals, with the ability to circulate between two states forever without losing energy, are one of the most important laws of physics. Second law of thermodynamics, It states that the disorder or entropy of isolated systems must constantly increase. These strange time crystals remain stable and resist dissolution to randomness, even though they exist in a constant flux state.
According to a research article posted on July 28 in the preprint database arXivScientists were able to use qubits (a quantum computing version of traditional computer bits) within the core of Google’s Sycamore quantum processor to create time crystals of approximately 100 seconds.
The existence of this strange new material phase and the completely new realm of physical behavior it reveals is very exciting for physicists. In particular, time crystals were first predicted to exist only nine years ago.
“This was a big surprise,” Curt von Keyserlingk, a physicist at the University of Birmingham in the United Kingdom, who was not involved in the study, told Live Science. “If I asked someone 30, 20, or 10 years ago, they wouldn’t have expected this.”
Time crystals are attractive objects for physicists because they essentially circumvent one of the most iron-clad laws in physics, the second law of thermodynamics. He states that entropy (a rough analog of the amount of disorder in the system) is constantly increasing. If you want to make something more orderly, you need to put more energy into it.
This tendency for greater disorder explains many things, such as why it’s easier to mix the material into the mixture than to separate it again, and why the headphone cord gets tangled in the pants pocket. It also sets the arrow of time, and the universe of the past is always more orderly than the present. For example, if you look at the video in reverse, it can look strange, primarily because you’re witnessing this counterintuitive reversal of entropy flow.
Time crystals do not follow this rule. Instead of slowly approaching thermal equilibrium, instead of “thermalizing” energy or temperature so that it is evenly distributed throughout the environment, it stacks between two energy states above equilibrium and between them. It circulates indefinitely.
To explain how unusual this behavior is, von Keyserlingk said he would draw a sealed box filled with coins before being shaken a million times. When the coins bounce off each other and bounce off, they “explore all sorts of configurations that can be explored and become more and more chaotic” until the sway stops. A box will open and coins will be displayed randomly. About half of the coins are facing up and half are facing down. You can expect to see this random half-up and half-down endpoint regardless of how the coins in the box were first placed.
Inside Google’s Sycamore “box”, you can display the qubits of the quantum processor in the same way as coins. Just as a coin is either front or back, a cubit is either 1 or 0 (two positions possible in a two-state system), or a strange combination of probabilities for both states called superposition. Is it? According to von Keyserlingk, the strange thing about Time Crystal is that the amount of swaying and zapping from one state to another cannot move the Time Crystal’s qubit to a random composition, the lowest energy state. That is. You can only flip from the start state to the second state and then back again.
“It’s a kind of flip-flop,” said von Keyserlingk. “It doesn’t look random, it just gets stuck. It seems like you remember what it looked like at first, and the pattern repeats over time.”
In this sense, the time crystal is like a pendulum that never stops shaking.
“Even if the pendulum is completely physically isolated from space, it will eventually stop without friction or drag. This is due to the second law of thermodynamics,” says Physics at Lafbara University. Scholar Achilleas Lazarides said. Britain, one of the first scientists to discover the theoretical potential of a new phase in 2015, told Live Science. “Energy begins with the focus on the center of gravity of the pendulum, but there are all these internal degrees of freedom. atom It can vibrate inside the rod — eventually moving to the rod. “
In fact, there is no way for large objects to behave like time crystals without sounding absurd. The only rule that allows the existence of a time crystal is the eerie and surreal rule that dominates a very small world. Quantum mechanics..
In the quantum world, objects behave like both point particles and small waves at the same time, and the magnitude of these waves in any region of space represents the probability of finding a particle at that location. However, randomness (such as random defects in the crystal structure or programmed randomness of the strength of the interaction between the cubits) allows the probability wave of the particle to be canceled anywhere except in one very small region. There is sex. It is rooted in place and cannot move, change state, or heat with its surroundings, and the particles are localized.
Researchers used this localization process as the basis for their experiments. Uses 20 superconducting strips aluminum Scientists have programmed each qubit into one of two possible states. Next, by irradiating the strip with a microwave beam, we were able to drive the qubit and invert the state. The researchers repeated the experiment with tens of thousands of runs and stopped at various points to record the state of the qubit. What they found was that the qubit collection was flipped back and forth between the two configurations, not the qubit. It also absorbs heat from microwave beams — they made thyme crystals.
They also saw an important clue that their time crystal was a phase of matter. What is considered a phase usually needs to be very stable in the face of fluctuations.Solids do not melt in the following cases temperature The surroundings of them are slightly different. The liquid does not evaporate or freeze suddenly due to slight fluctuations. Similarly, even if the microwave beam used to invert the qubit between states is close to the exact 180 degrees required for full inversion, but adjusted to shift slightly, the qubit is otherwise. Inverts to the state of.
“If it’s not exactly 180 degrees, it won’t be scrambled,” Lazarides said. “that [the time crystal] Even if you make a slight mistake, you will magically insert chips little by little. “
Another characteristic of moving from one phase to another is breaking physical symmetry. The idea is that the laws of physics are the same for objects at any point in time or in space. As a liquid, molecules in water follow the same laws of physics at all points in space and in all directions, but water turns into ice and the molecules choose regular points along their crystal structure (or lattice). Let it cool down enough. Place yourself across. Suddenly, water molecules have a favorable point to occupy in space, and the other points remain empty — the spatial symmetry of water was spontaneously broken.
Just as ice breaks in space symmetry to crystallize in space, time crystals break in time symmetry to crystallize in time. First, the qubit sequence experiences continuous symmetry between all moments of time before they are converted to the time crystal phase. However, the periodic cycle of the microwave beam chops the constant conditions experienced by the qubit into discrete packets (making the symmetry imposed by the beam discrete time-transforming symmetry). The qubit then breaks with the discrete time-transformation symmetry imposed by the laser by flipping back and forth with a period twice the wavelength of the beam. These are the first objects that we know can do this.
All of this strangeness makes time crystals rich in new physics, and the controls that Sycamore provides to researchers beyond other experimental settings can make it an ideal platform for further investigation. I can do it. But I’m not saying that it can’t be improved. Like all quantum systems, Google’s quantum computers are completely out of the environment to prevent qubits from undergoing a process called decoherence, eventually destroying the quantum localization effect and destroying time crystals. Must be separated into. Researchers are working on ways to better isolate the processor and mitigate the effects of decoherence, but the effects are unlikely to be permanently eliminated.
Nevertheless, Google’s experiments may continue to be the best way to study foreseeable future time crystals.Many other projects have succeeded in creating something that looks like a compelling time crystal in other ways, but diamonds, helium-3 superfluids, quasiparticles called magnons, and Bose-Einstein Condensation — In most cases, the crystals produced by these setups will dissipate too quickly for further study.
The theoretical novelty of crystals is, in a sense, double-edged swords, as physicists are currently struggling to find their clear uses, but von Keyserlingk can use them as precision sensors. Suggests. Other suggestions include using crystals for better memory storage or to develop quantum computers with even faster processing power.
But in another sense, the greatest use of time crystals may already be here. They allow scientists to scrutinize the boundaries of quantum mechanics.
“This allows us not only to study what appears in nature, but to actually design it and see what quantum mechanics can and cannot do,” says Lazarides. “If you can’t find something in nature, it doesn’t mean it can’t exist. We just created one of them.”
Originally published in Live Science.
Another-world “time crystals” created within Google Quantum Computers have the potential to change physics forever
https://www.space.com/google-invents-time-crystal Another-world “time crystals” created within Google Quantum Computers have the potential to change physics forever