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Quantum computers make it possible to make time crystals

The consensus is that the next generation of computing and information processing lies in the fascinating and rich world of quantum mechanics. Quantum computers are thought to be able to solve large and very complex problems that the most powerful supercomputers today can not handle. However, the construction of quantum computers naturally faces a number of problems that practically delay the achievement of the useful type of these massive processing machines for years.

In recent years, fortunately, many researchers, governments, private companies, and scientific institutions have entered the field of quantum computing; For this reason, we are increasingly discovering solutions and initiatives that can give us hope for the future of quantum computing.

At present, scientific institutions testing quantum computers have begun to build companies such as IBM, Rigti, and D-View. Chinese companies like Alibaba also have access to quantum computers. Some businesses are buying these computers; Others use quantum-based cloud computing.

Although there are still major obstacles to building such a quantum computer, today’s prototypes can still do the trick. For example, these computers could create a new phase of matter called a “time crystal or four-dimensional crystal.” The time crystal is actually an alternating structure that repeats itself in time and space. Three-dimensional natural crystal has a pattern of repetition in space; But in time it remains unchanged.

Just as the ordinary crystal structure is repeated in space, the time crystal is repeated in “time,” and more importantly, it does so infinitely without any energy input. To better understand its amazing feature, imagine a watch that works forever without a battery. Of course, trying to realize this stage of matter has so far been a daunting challenge in theory and experiment; But it seems to have finally come to fruition.

In a recent study published in the journal Nature, a team of scientists from Stanford University, Google Quantum Artificial Intelligence, the Max Planck Institute for Complex Systems Physics, and the University of Oxford detailed the creation of time crystals using Google’s Sicamor quantum computing hardware.

Matthew Epolith, Says a Stanford University researcher and one of the authors of the article:

The big picture is that we are using devices that are supposed to be the quantum computers of the future, and we consider them as complex quantum systems of our kind. Instead of calculations, we use the computer as a new experimental platform to understand and detect new phases of matter.

In general, the new achievement of researchers is not limited to creating a new stage of matter; Rather, it provides opportunities to explore more detail in the field of solid-state physics, which studies new phenomena and properties resulting from the collective interactions of many objects in a system.

Vadika Khamani, Stanford, an assistant professor of physics, explains:

Time crystals are a prime example of a new type of non-equilibrium quantum phase of matter. While much of our understanding of solid-state physics is based on equilibrium systems, these new quantum devices offer amazing avenues for new non-equilibrium states in multiprocessor physics.

[فیزیک چندپیکره (many-body physics) حوزه‌ای از فیزیک است که اغلب به‌ترتیب عدد آووگادرو چهارچوبی برای درک رفتار جمعی تعداد زیادی از ذرات برهم‌کنش فراهم می‌کند. به‌طور‌کلی، نظریه‌ی چندپیکره به اثرهایی می‌پردازد که خود را فقط در سیستم‌های دارای تعداد زیادی مؤلفه نشان می‌دهند.]

Quantum computer

The raw materials for making this time crystal include the physical equivalent of the fruit fly and what it climbs on. In fact, the fly is the fruit of Ising’s physics model; An old tool for understanding various physical phenomena, including phase and magnetic transitions, which consist of grids in which each space is occupied by particles that can be displayed in two modes, rotating up or down.

It is said that during the postgraduate years, Khamenei, And Shivaji Sundi، Achilles Azarides And Rudrich Mussner The Max Planck Institute accidentally obtained this command to make unwanted time crystals. Apparently, they were studying non-equilibrium multivariate local systems; Systems in which particles get stuck in the state in which they started and can never be released into equilibrium.

They were interested in exploring the steps that might be taken in such systems when they change periodically by laser. Finally, researchers not only succeeded in finding stable non-equilibrium phases; Rather, they found a phase in which the rotation of particles between patterns that repeat themselves over time changed at intervals of twice the period of laser motion.

The impact of laser cycles creates a certain rhythm for dynamism. Usually the up and down rotations have to keep pace with this rhythm; But this is not the case with time crystals. Instead, the rotations switch between two modes and complete a cycle after only two laser strokes. This means that the temporal translation symmetry of the system is broken. Symmetries play a major role in physics and are often broken. This is the process that explains the origin of regular crystals and magnets and many other phenomena.

However, the symmetry of temporal translation is stable and, unlike other symmetries, it cannot be broken in equilibrium. Intermittent laser beats, meanwhile, are apertures that make time crystals possible. As we said at the beginning, the most important feature of the time crystal is that this system of millions of components produces this kind of coordinated behavior without the entry or leakage of energy.

سوندی, An Oxford physics professor and co-author of the article, says:

This is a very large stage of matter in which you do not set parameters or states; But your system is still quantum. In this system, there is no source of energy and energy discharge and it lasts forever and includes many particles with strong interaction.

This process may be strangely close to building a machine (any type of machine) with a permanent energy source; But a closer look reveals that time crystals do not violate any physical laws. Entropy, a measure of irregularity in a system, remains constant over time and satisfies thermodynamics to some extent without diminishing the second law.

It is interesting to note that before this many experiments were carried out by different teams of researchers between the development of this design for time crystals and the experiment of quantum computers in order to realize it, and incidentally reached milestones in the construction of time crystals. However, providing all the ingredients in the instructions for multicomponent localization remained an important problem.

In fact, it’s the product of research by Khamani et al., And the last step in Crystal’s success when working with a team at Quantum AI belonged to Google. The team used Sicamor’s quantum computing hardware to program 20 “spins” and a quantum version of the bits of classical computer information known as qubits.

The researchers were able to confirm their claim of a real-time crystal thanks to the special capabilities of a quantum computer. The small scale and coherence time of the quantum apparatus indicated that their experiments were very limited in size and duration; So that crystalline time fluctuations can be observed only for a few hundred cycles. The researchers developed various protocols to evaluate the stability of their creation, including performing back-and-forth simulations in time and scaling their size.

Musner, director of the Max Planck Institute for Complex Systems Physics, says:

We were able to use the adaptability of quantum computing to help parse its constraints. The quantum computer showed us how to correct our mistakes; So that the effect of the ideal time crystal behavior can be determined from finite time observations.

One of the important signs of an ideal time crystal is that it shows infinite oscillations from all states. Confirmation of this robustness in state selection was an important experimental problem, and researchers developed a protocol that required only milliseconds of runtime to explore more than one million states of their time crystal in just one run of the device. It is like observing a physical crystal from different angles to confirm its repetitive structure; Therefore, the use of Google’s quantum computer has played a significant role in this achievement.

شیائو می, Says Google researcher:

The unique feature of our quantum processor is its ability to create very complex quantum states. These states allow the phase structure of matter to be effectively validated without the need to examine the entire computational space.

In general, a new stage of matter at the fundamental level is very important and exciting. The fact that the researchers were able to do this illustrates the rare use of quantum computers for non-computational tasks.

Pedram Roshan, Says a Google researcher:

I am optimistic that with more and better qubits, our approach can become the main method for studying unbalanced dynamics.


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