Time crystals are exciting. Theoretical physicists have toyed with them since the American Frank Wilczek, laureate of the Nobel Prize in Physics in 2012. At that time, the scientific community received the idea with great skepticism, But little by little Wilczek’s proposition is going deeper and adding followers. So many, in fact, that there are currently several research groups focused on this exotic discipline.
We’ve already talked about them on several occasions, but before going any further, we need to review who crystals are, what they’re for, and how they’ve evolved over the past decade. Like any other crystal, the atoms in these structures are distributed in a homogeneous and orderly manner, shaping a periodically repeating pattern.
However, there is a fundamental difference between ordinary crystals and Wilczek crystals: in the former the pattern is repeated in space, whereas in the latter it is, and this is surprising, on time, It is difficult to imagine an object with this property, but there is something we cannot ignore: to form a crystal like the ones proposed by this physicist, it is necessary to find a way to break temporal symmetry spontaneously .
Time crystals are possible. In fact, the first ones are already ready
A stationary object isolated from any disturbance remains unchanged over time, so it preserves time translation symmetry. However, a time crystal must be able to simultaneously maintain its stability and periodically change its crystal structure. This idea has an implication that is easy to understand: if we look at the time crystal at different moments, we must understand that its structure is not always the same.
It must vary from time to time, a behavior that inevitably leads us to identify a new state of matter Differentiate between solid, liquid, gas and plasma phases. Under certain conditions, other much more unusual states of matter are also possible, such as a Bose–Einstein condensate, but to a greater or lesser extent we are all familiar with these four phases.
Time crystals change their structure with a certain periodicity and recover their initial configuration at regular intervals.
Despite the scientific community’s initial misgivings, some researchers considered what Wilczek was proposing and realized that under some highly unlikely, but possible circumstances, some objects could theoretically exhibit the behavior of a time crystal. Are. They should be able to change their structure with some regularity and recover their initial configuration at regular intervals.
The idea is certainly very exotic, but it has an even stranger implication: it is only possible if it is a continuous and eternal phase transition. No need to invest energy, Somehow we may be facing an impossible ideal: a form of a perpetual motion machine that benefits from the principle of conservation of energy, but clearly violates the second law of thermodynamics.
This fundamental law states that the entropy of an isolated thermodynamic system always increases with the passage of time until it reaches a state of thermodynamic equilibrium in which it is maximum. This formal definition is somewhat intuitive, mainly because the term entropy appears twice in it. Strictly explaining what entropy is would complicate the article even more, but we can explain the concept in a simple way for a long time, yes, we admit to sacrifice a bit.
Entropy is usually modeled as the degree of disorder naturally present in a physical system. This description is an oversimplification, but it invites us to explore an essential consequence of the second law of thermodynamics: the impossibility of reversing a physical phenomenon, Furthermore, what Wilczek proposes goes against the first law of thermodynamics, or the principle of conservation of energy, which basically establishes that energy is neither created nor destroyed; becomes.
We already know with some precision what a time crystal is, so we set out to receive a pleasant surprise with open arms: the research group at Lancaster University in the United Kingdom, led by physicist Samuli Otti, the first Succeeded in getting a spot. point in mid-2022. In the article published by this research group in Nature Communications, it has been told that the crystals of its time are made of magnon. And the interesting thing is that these elements are not particles; There are spin 1 quasiparticles capable of transporting energy and momentum in a crystal.
We can understand a magnon as the result of the simultaneous excitation of the spins of a set of electrons
This definition is complicated, but we can make a rough idea of it. what is magnon If we recognize this as the result of simultaneous excitation of the spins of a set of electrons. This explanation by Francis Villetoro helps us to frame the idea a bit better: “We can say that a magnon is the quantum equivalent of a spin wave, just as a phonon is the quantum equivalent of an elastic wave in a solid.”
The strategy these physicists have devised to recreate magnons involves cooling helium-3, a stable isotope of helium, until it is very close to absolute zero (-273.15 °C). temperature is not reached. Under these conditions, helium-3 acquires the properties of a superfluid and supports the spontaneous formation of time crystals, so that each of them is composed of trillions of magnons. And it’s about a billion of us, not Anglo-Saxons.
In their article, Auty and his research colleagues claim to have recreated the time crystal. display similar properties Formulated theoretically by Frank Wilczek, so there is no doubt that we are facing a very important milestone. And it is relevant because of the theoretical scope of its potential applications. Researchers working on the design of time crystals are confident that they can be used to measure time and distance with extreme precision.
Scientists believe that fine-tuning the quantum bits using time crystals will give them greater coherence.
If so, they could potentially be used to develop more accurate GPS, more advanced telecommunications equipment, or more robust cryptographic systems. But this is not all. Furthermore, the team of researchers led by Auty argues that time crystals can help us process quantum information because it is possible to use them to create high-quality qubits.
These scientists imagine using time crystals to fix quantum bits it will give them more coherence Understanding this property as the ability to prolong the time in which quantum hardware preserves the characteristics that allow it to outperform classical computers during the execution of certain algorithms.
And it is that when quantum decoherence appears, quantum effects disappear, and with them the advantages that they bring in the context of quantum computing. Furthermore, these researchers maintain that time crystals can be made and manipulated at room temperature, so that, in principle, they could allow tuning of qubits, unlike superconductors, as long as they are perfect. Do not cool until temperature is reached. Zero.
The latest in time crystals: photonic metamaterials
The most recent contribution to the field of time crystals has been made by a team of researchers at the University of Southampton in the United Kingdom, led by physicist Nikolay I. Zheludev. In an article they published in Nature Physics to publicize their work, the scientists report that they have succeeded in growing a constant time crystal using a photonic metamaterial,
When they interact with light, the molecules of this metamaterial rearrange themselves and trigger a spontaneous phase transition.
At the moment there is no unanimously accepted definition of what a metamaterial is, but we can view it as an artificial structure with unusual electromagnetic properties that do not need to be aligned with the elements that make it up separately. What is interesting about the material these researchers have prepared is that the interaction with a light that is able to resonate with its molecules triggers a spontaneous phase transition.
In practice this means that when light falls on it, its molecules interact with each other and cause the material to change position and start oscillating continuously, This behavior fits like a glove with the properties of time crystals modeled by Frank Wilczek, so there’s no doubt that the discovery made by Zeludeev and his colleagues is very promising. As the title of this article says, the time crystals are already here. And they will be.
