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This article comes from the official account of Wechat: back to Park (ID:fanpu2019), by Natalie Volchefo (Natalie Wolchover), and translated by Liu Hang.

Although the standard model is considered to be one of the most successful physics theories in history, there are more and more signs that the standard model has a crisis in recent years. In fact, the standard model has not been perfect since its birth, or even a self-consistent theory. It is "unnatural", especially about the "hierarchy problem" caused by the quality of the Higgs boson, which has not been fundamentally answered so far. There is a simple and convenient theory to explain these problems, that is, supersymmetry theory, but in terms of experiments, the most powerful collider has not found any supersymmetric particles so far. This forces many physicists to rethink the nature of the model, and perhaps at the most basic level, reductionism does not solve the problem, even though it has led the development of physics over the past few hundred years. Now, many physicists have found a "mixed" mode with different energy targets to solve the problem of "naturalness", breaking the original form of reductionism.

For nearly three decades, scientists have been searching in vain for new elementary particles to explain what we have observed about nature. When physicists face the failure of the search for new particles, they have to rethink a long-standing assumption that big things are made up of small things.

In the classic structure of the Scientific Revolution by the philosopher of science, Thomas Kuhn, Kuhn observes that scientists sometimes take a long time to take a small step. They pose a problem and integrate all the data within a fixed worldview or theoretical framework to solve it, which Kuhn calls a Paradigm. Sooner or later, however, the fact that it conflicts with the mainstream paradigm will suddenly emerge. The crisis followed. Scientists racked their brains to re-examine their assumptions and eventually made a revolutionary shift to a new paradigm with a fundamentally different and more realistic understanding of nature. And then resume the steady progress of science.

For years, particle physicists who study the most basic components of nature have been in this textbook Kuhn crisis.

The crisis became undeniable in 2016. Despite major upgrades at the time, the large Hadron Collider (LHC) in Geneva has not "summoned" any new elementary particles-theorists have been waiting for decades. The additional particle swarm will mainly solve a problem about a known particle, the famous Higgs boson. The problem is called the Hierarchy problem, "Why is the Higgs boson so light"-1017 times smaller than the highest energy scale that exists in nature. Compared to the higher energies, the mass of the Higgs seems to be unnaturally small, as if the huge numbers in the basic equation that determine its value have been miraculously offset.

The extra particles could explain why the mass of the Higgs is so small (relative to the Planck scale), restoring what physicists call "Naturalness" in their equations. After the large Hadron Collider became the third and largest collider, physicists still did not find them. This suggests that what exactly is natural logic in our current theory of nature may be wrong. "We need to rethink the guiding principles that have been used for decades to solve the most basic problems in the physical world." That's what Gian Giudice, head of the theoretical department of CERN, said in 2017.

At first, the particle physics community was desperate. "you can feel a kind of pessimism." Isabel Garcia Isabel Garcia Garcia, a particle theorist at the Caffrey Institute for theoretical Physics at the University of California, Santa Barbara, said she was a graduate student at the time. The truth is that not only has the $10 billion Proton Collider failed to answer a question from 40 years ago, but even the beliefs and strategies that have long guided particle physics are no longer unbreakable. People want to know more than ever whether the universe we live in is really unnatural, just the product of a fine-tuned mathematical offset. In fact, there may be a multiverse, and all universes have randomly adjusted Higgs masses and other parameters; we find ourselves living here only because the unique properties of our universe promote the formation of atoms, stars and planets, leading to the birth of life. While this "Anthropic argumen" theory may be correct, it is frustratingly unverifiable.

Nathaniel Craig, a theoretical physicist at the University of California, Santa Barbara, says many particle physicists turn to other areas. "the problems in other areas are not as thorny as hierarchical ones," said Nathaniel Craig, a theoretical physicist at the University of California, Santa Barbara.

Nathaniel Craig (Nathaniel Craig) and Isabel Garcia (Isabel Garcia Garcia) explore how gravity can help reconcile very different energy scales in nature. Photo Source: Jeff Liang some physicists are going to carefully study the hypothesis made several decades ago. They began to rethink the remarkable unnatural features of nature, which seem to have undergone unnatural fine adjustments, such as the small mass of the Higgs boson and the seemingly unrelated fact that space itself is unnaturally low in energy. "the real fundamental problem is the problem of naturalness." Garcia said.

Their reflective work is bearing fruit. Researchers are increasingly concerned about the weaknesses in the traditional reasoning of naturalness. It is based on a seemingly moderate assumption that has been considered scientific since ancient Greece: that big things are made up of smaller, more basic things-an idea known as Reductionism. Nima Akani-Hamid (Nima Arkani-Hamed), a theoretical physicist at the Princeton Institute for Advanced Studies, said: "the reductionist paradigm is closely related to the problem of nature."

Now, more and more particle physicists believe that natural problems and the zero result of the large Hadron Collider may be related to the failure of reductionism. "will this change the rules of the game?" Akani Hamid asked. In a series of recent papers, researchers have left reductionism behind. They are exploring new ways to work together on different scales to arrive at parameter values that are unnaturally fine-tuned from a reductionist point of view.

"some people call it a crisis. There's an atmosphere of pessimism, but I don't think so," Garcia said. "I think now is the time to do something profound."

What is naturalness? In 2012, the large Hadron Collider (LHC) finally made its most important discovery-the Higgs boson, which is the cornerstone of the 50-year-old Standard Model of Particle Physics (Standard Model, SM), which describes 17 known elementary particles.

The discovery of the Higgs particle confirms a fascinating story described in the standard model equation. Moments after the Big Bang (Big Bang), an entity called the Higgs field was suddenly filled with energy. The high-energy Higgs field is filled with the Higgs boson, and the elementary particles gain mass from the energy of the Higgs field. When electrons, quarks and other particles move through space, they interact with the Higgs boson and gain mass in this way.

In 1975, the standard model was completed, and its builders noticed a problem almost immediately [1].

When the Higgs gives mass to other particles, the mass of other particles in turn affects the mass of the Higgs; all particles interact with each other. Physicists can write an equation for the mass of the Higgs boson, which includes the action of each particle that interacts with it. All the mass standard model particles found have contributed to the equation, but other contributions should be included in the equation in principle. The Higgs particle should be mixed (interacting) with mathematically heavier particles until it includes Planck-scale phenomena, that is, energy levels associated with the quantum properties of gravity, black holes and the Big Bang. The phenomenology of the Planck scale will in principle contribute a huge order of magnitude to the Higgs mass-about 1017 times the actual Higgs mass. Naturally we would expect Higgs bosons to be about as heavy as them, thus increasing the mass of other elementary particles. In this way, the particles will be too heavy to form atoms, and the universe will be empty.

In order to explain why the Higgs depends on such a high energy but so light, it must be assumed that part of the Planck scale's contribution to its mass is negative, while the other part is positive, and both are fine-tuned to counteract it completely. This seems absurd, unless for some reason-just like counteracting the airflow and the vibration of the table in order to balance the tip of the pencil. Physicists believe that this fine adjustment and cancel each other out is "unnatural".

Over the next few years, physicists found an ingenious solution-supersymmetry, a theory that assumes the doubling of elementary particles in nature. In supersymmetry theory, each boson (spin is an integer) has a supersymmetric companion fermion (spin is a semi-integer), and vice versa. Bosons and fermions contribute positive and negative terms to Higgs mass, respectively. Therefore, if the two always appear in pairs, then they will always cancel each other out.

Since the 1990s, the large Electron Positron Collider (Large Electron-Positron Collider) has been looking for supersymmetric partners. The researchers assumed that the particles were only slightly heavier than their standard model partners and needed more collision energy to achieve, so they accelerated the particles to close to the speed of light, smashed them, and then looked for heavy companions in the debris.

Hierarchy problem: the Higgs boson gives mass to other elementary particles, which in turn affect the mass of the Higgs particle. Supermassive particles on the Planck scale (the high-energy scale associated with quantum gravity) should inflate the mass of the Higgs boson and the mass of all other matter. But this is not the case. Problem: the mass of the Higgs boson is hundreds of billions of times smaller than the Planck scale. Possible solution 1: the Planck scale effect is truncated because the more complete Higgs boson theory is effective at higher energies. Possible solution 2: the Higgs scale and Planck scale are linked through a complex set of push-pull effects. Photo Source: Merrill Sherman for Quanta Magazine vacuum, even if there is no matter, seems to be full of energy-all the fluctuations of quantum fields run through it. When particle physicists add up all possible contributions to space energy, they find that, like the Higgs mass, the injection of energy from Planck scale phenomenology explodes its mass (the mass is infinite). Albert Einstein (Albert Einstein) proved that the space energy which he called the cosmological constant (Cosmological constant) has the gravitational repulsion effect. It makes the space expand faster and faster. If Planck-scale energy density were injected into space, the universe would tear apart immediately after the Big Bang. But that didn't happen.

On the contrary, cosmologists have observed that the expansion of space is only accelerating slowly, indicating that the cosmological constant is very small. The results of measurements in 1998 show that the energy of the fourth power of the first stroke is 1030 times lower than that of Planck. This time, the input and output of all the huge energy in the cosmological constant equation seem to be perfectly offset, leaving an unusually calm vacuum.

"Gravity. Physics that mixes all the length scales-short distance, long distance. Because of its characteristics, it has found a way out for the problems we encounter."

-Nathaniel Craig Nathaniel Craig

These two major natural problems were obvious in the late 1970s, but for decades, physicists thought they were unrelated. "people were crazy about it at that stage," said Arkani-Hamed. The problem of cosmological constants seems to have an implicit relationship with the mysterious quantum nature of gravity, because the energy of space can only be detected by gravitational effects. Hamid says the hierarchy problem looks more like a "dirty little detail problem", which, like other difficult problems in the past, will eventually reveal some missing parts of the theory. When the Higgs boson is so light, Judy calls it "Higgs boson disease", which cannot be cured by a few supersymmetric particles in the large Hadron Collider.

In hindsight, these two questions about nature are more like different manifestations of the same deeper problem.

"it's useful to think about how these questions come about," Mr. Garcia said in a telephone interview with Zoom from Santa Barbara this winter. "the problems of hierarchy and cosmological constants arise in part because of the tools we try to answer questions-the way we understand the characteristics of the universe."

The accurate prophecy of reductionism physicists honestly calculated the Higgs mass and cosmological constants in their way. The calculation method reflects the peculiar nest doll structure of the natural world.

Zoom in on an object and you will find that it is actually made up of many smaller things. Galaxies far away from us are actually a collection of huge stars; each star is made up of many atoms; each atom can be further broken down into a subatomic hierarchy. In addition, when you zoom in to a shorter distance scale, you will see heavier, higher-energy elementary particles and phenomena-- the deep connection between high-energy and short-range, which explains why the High-Energy Particle Collider is like a microscope in the universe. The connection between high energy and short distance is reflected in many aspects of physics. For example, quantum mechanics says that a particle is a wave; the greater the mass of the particle, the shorter the correlation wavelength. Another view is that energy must be gathered more densely to form smaller objects. Physicists call low-energy, long-distance physics "IR" and high-energy, short-distance physics "UV". This is an analogy between the infrared band (IR) and the ultraviolet band (UV) of light.

In the 1960s and 1970s, particle physics giants Kenneth Wilson and Steven Weinberg pointed out the beauty of natural energy level structures: if we are only interested in what happens on the macro infrared scale, then we do not need to know what is "really" happening on the more microscopic, ultraviolet scale. For example, you can use a hydrodynamic equation to simulate water, treating water as an ideal fluid and ignoring the complex dynamics of water molecules. The hydrodynamic equation includes a term that characterizes the viscosity of water-a quantity that can be measured under the infrared energy scale, which includes the interaction of all water molecules under the ultraviolet energy scale. Physicists say the infrared and ultraviolet energy labels are "decouple" from each other, allowing them to effectively describe the world without having to study the deepest situation. The ultimate ultraviolet energy scale, the Planck scale, corresponds to 10-35 meters, or 1019GeV energy. There may be another scene in such a fine space-time structure.

Kenneth Kenneth Wilson, an American condensed matter and particle physicist who was active from the 1960s to the early 21st century, developed a mathematical method (lattice quantum field theory) to describe how the properties of a system change with the scale of measurement. Photo Source: Cornell University faculty file # 47-10-3394, Department of cherished Resources and manuscript Collection, Cornell University Library. "We can still do physics research because we don't have to know what's going to happen in a short distance," said Riccardo Rattazzi, a theoretical physicist at the Federal Institute of Technology in Lobsang, Switzerland.

Like different levels of the nesting doll world, how do particle physicists simulate it? Wilson and Weinberg independently developed their own framework: effective field theory (Effective field theory,EFT). In the context of effective field theory, the problem of naturalness appears.

Effective field theory can simulate a system within a certain range of energy levels. Take a beam of protons and neutrons as an example, magnifying protons and neutrons, they appear to be protons and neutrons; in this range, chiral effective field theory (Chiral EFT) can be used to describe their dynamics. However, if the effective field theory is further enlarged, the effective field theory will reach its "ultraviolet truncation", that is, in the range of short distance and high energy level, the chiral effective field theory will no longer be an effective description of the system. For example, at the cut-off point of 1GeV, chiral effective field theory fails because protons and neutrons no longer behave like individual particles, but like three quarks. And a different theory began to take effect.

It should be noted that there is a reason why the effective field theory fails at its ultraviolet truncation. Truncation means that new, higher-energy particles or phenomenology must be found here, and these new particles or phenomena are not included in the original effective field theory. So how to solve this problem?

In its applicable energy region, scientists use effective field theory to absorb unknown effects higher than truncated ultraviolet physics into the "correction" term. It's as if the fluid equation has a viscous term to capture the net effect of short-distance molecular collisions. Physicists can write these corrections without knowing the real physics at the truncation; they just use critical values to estimate the magnitude of the impact.

In general, at the infrared energy scale, when you calculate the amount of interest, the UV correction is very small and is proportional to the length scale (relatively small) associated with truncation. However, the situation is different when you use the effective field theory to calculate parameters with mass or energy units, such as the Higgs boson mass or cosmological constant. The ultraviolet correction of these parameters is very large, because the correction is proportional to the energy, not to the corresponding length of the truncation. So although the length is very small, the energy is very high. Such parameters are called "ultraviolet sensitive" (UV-sensitive).

Effective field theory is a strategy to determine where its theory must be truncated (that is, the energy scale of the emergence of new physics). The concept of naturalness appeared together with the efficient field theory itself in the 1970s. The logic goes like this: if a mass or energy parameter has a high cutoff point, then its value should naturally be large and pushed higher by all UV corrections. Therefore, if the parameter is small, the truncation energy should be low.

Some critics think that naturalness is only an aesthetic preference. But others point out that this strategy reveals the hidden truth of nature. "this logic is feasible." Craig said. He is the leader in rethinking this logic recently. The problem of naturalness has always been like a signpost, reminding us where there are changes in the picture and the emergence of new physics. "

The brilliance of naturalness in 1974, a few years before the word "naturalness" emerged, Mary K. Gaillard and Benjamin Whisoh Lee used this strategy to amazingly predict the mass of a hypothetical particle, charm quark (charm quark). "her successful predictions and their relevance to hierarchical issues are grossly underestimated in our field of research," Craig said. "

In the summer of 1974, Gerrard and Lee were puzzled by the difference in mass between the two K mesons (composite particles made up of positive and negative quarks). The measured value of poor quality is very small. But when they tried to calculate the mass difference using the equation of effective field theory, they found that its value was at risk of spillover. Because the mass difference of K meson has a mass unit, it is sensitive to ultraviolet and obtains high energy correction from unknown physics at the truncation. The cutoff value of this theory is not known, but physicists at that time thought it could not be very high, otherwise the resulting K-meson mass difference would be surprisingly small compared to the modified value-as physicists now say, this is unnatural. Gerrard and Lee inferred that its truncated energy mark in the effective field theory is relatively low, at which the new physics should be revealed. They infer that the mass of a particle called charm quark proposed by the newcomer at that time should not exceed 1.5 GeV.

Three months later, the charm quark was discovered by the experiment, weighing up to 1.2 GeV. This discovery triggered a cognitive renaissance known as the November Revolution and quickly led to the completion of the Standard Model. In a recent video call, the 82-year-old recalled that she was visiting CERN in Europe when the news came out. Li sent her a telegram: found charm quarks.

In 1974, Mary K. Gaillard and Ben Lee used the naturalness argument to predict the mass of a hypothetical elementary particle called charm quark. Charm quarks were discovered a few months later. AIP Emilio Segr è Visual Archives's victory has convinced many physicists that the new particles predicted by the hierarchy problem should not be much heavier than the standard model. If the cutoff point of the standard model is as high as close to the Planck energy mark (if so, scientists must know that the standard model has failed because quantum gravity is not taken into account). Then the ultraviolet correction to the Higgs mass would be huge-such a light Higgs mass would naturally be unnatural. If the cut-off point is not far above the Higgs boson mass, it will make the mass of the Higgs similar to the correction from the cut-off point, and everything will look natural. "the choice of cut-off points is the starting point of efforts to solve the problem of hierarchy over the past 40 years." "people have come up with great ideas, such as supersymmetry, [Higgs] complexity and other possibilities that we haven't seen in nature yet," Garcia said. "

After a few years of studying for a doctorate in particle physics at Oxford University in 2016, Garcia was well aware that liquidation was necessary. "I started to be more interested in the missing parts, and we usually don't include this part when we talk about these issues, that is, gravity-recognizing that quantum gravity is much richer than we can learn from effective field theory."

Gravity mixes everything. In the 1980s, theorists learned that gravity did not conform to the usual rules of reductionism. If you hit the two particles hard together, the energy will gather at the collision point and even form a black hole-an area where gravity is so strong that nothing can escape. If the particles hit each other more violently, they will form a larger black hole. More energy does not allow you to see a shorter distance; the harder you hit each other, the larger the invisible area-which contradicts reductionism. The black hole and the theory of quantum gravity that describes its interior completely overturn the usual relationship between high energy and short distances. "Gravity is anti-reductionist." Says New York University physicist Sergei Dubowski (Sergei Dubovsky).

Quantum gravity seems to joke with the architecture of nature. "physicists who use effective field theory have become accustomed to simple and ingenious nested energy marker systems, and quantum gravity makes a mockery of it." Craig, like Garcia, began to think about the effects of gravity shortly after finding nothing in the search for the large Hadron Collider. While trying to solve the hierarchical problem in a variety of new ways, Craig reread a 2008 article on nature by Judith, a theoretical physicist at CERN. The solution to the cosmological constant problem may involve "some complex interactions between infrared and ultraviolet effects," and Craig began to think carefully about its implications, Judy wrote. If infrared and ultraviolet have complex interactions, it will violate the usual decoupling, and the decoupling of infrared and ultraviolet is the basis for the effective field theory to work. " I Googled keywords like'UV-IR hybrid'. Craig said it led him to some interesting papers from 1999, "and then I started thinking about that direction."

By breaking the reductionist system of effective field theory, UV-IR mixing may solve the problem of naturalness. In effective field theory, quantities such as Higgs mass and cosmological constants are UV-sensitive, but for some reason they do not explode, as if there was a collusion between all ultraviolet physics-- all ultraviolet effects were offset. Then the problem of naturalness arises. "in the logic of effective field theory, we give up this possibility." Craig explained. Reductionism tells us that infrared physics also comes from ultraviolet physics-- the viscosity of water comes from its molecular dynamics, the properties of protons come from its internal quarks, and when you zoom in on the energy scale, the interpretation shows-- not the other way around. However, UV is not affected or explained by infrared, "so the effect on the Higgs cannot be inferred from very different energy levels."

The question Craig is asking now is: "will the logic of efficient field theory fail?" Maybe interpretation can really flow in both directions between ultraviolet and infrared. "this is not entirely nonsense, because we know that gravity can do this." "Gravity does not satisfy the reasoning of normal effective field theory, because it mixes physics of all length scales-short distance, long distance," he said. because of this characteristic, we have found a way out for the problems we encounter. "

How UV-IR mixing protects naturalness several new studies on UV-IR mixing and how it solves the problem of naturalness can be traced back to two papers published in 1999. "people are increasingly interested in these more peculiar, ineffective field theory solutions." Patrick Draper (Patrick Draper) says he is a professor at the University of Illinois at Urbana-Champaign, and his recent work [3] continued to finish the unfinished part of the 1999 paper.

Draper and his colleagues studied CKN constraints (named after the authors of the 1999 paper, Andrew Cohen, David B. Kaplan and Ann Nelson). The author considers a model in which a large number of particles are put into a box and heated, and the energy of the particles increases until the box collapses into a black hole. They calculated that before the box collapsed, the number of high-energy particles that could be put into the box was proportional to the 3/4 power of the box's surface area, rather than the box's volume. They think this represents a peculiar UV-IR relationship. The size of the box sets the infrared scale, which seriously limits the number of high-energy particle states in the box-the ultraviolet scale.

Then they realized that if this constraint applied to our entire universe, the problem of cosmological constants could be solved. In this case, the observable universe is like a very large box. The number of high-energy particle states it can contain is proportional to the 3/4 power of the surface area of the observable universe, rather than the much larger volume of the entire universe.

This means that the usual effective field theory calculation of cosmological constants is naive. The calculation of the effective field theory tells us that when you zoom in on the spatial structure, the high-energy phenomenon should occur, and this should cause the energy of the space to explode. But the CKN constraint implies that there may be much less high-energy motion than assumed in the effective field theory calculation-which means that particles can occupy fewer high-energy particle states. A simple calculation by Cohen, Kaplan and Nelson shows that their constraints can explain the small values of observed cosmological constants for boxes the size of our universe.

Their calculations show that large and small scales may correlate in some way, and the correlation becomes obvious when you look at the infrared properties of the entire universe, such as cosmological constants.

In another rough calculation last year, Draper and Nikita Brinov (Nikita Blinov) confirmed that the CKN constraint successfully estimated the observed cosmological constants; they also showed that this method did not undermine many of the successes of effective field theory in lower-level experiments.

The CKN constraint does not tell us why ultraviolet and infrared are interrelated-that is, why the size of the box (infrared) severely limits the number of high-energy particle states in the box (ultraviolet). To know why, we may need to understand quantum gravity.

Other researchers look for answers in string theory, another specific theory of quantum gravity. Last summer, string theorists Steven Abel (Steven Abel) and Keith Dines (Keith Dienes) demonstrated how ultraviolet-infrared mixing in string theory can solve the problem of hierarchy and cosmological constants.

As a candidate for gravity and other basic theories, string theory holds that all particles are open or closed vibrating strings. Standard model particles such as photons and electrons are low-energy vibration modes of basic strings. But strings can also vibrate more forcefully, producing an infinite spectrum of string states with higher energy. In this case, the question of hierarchy is concerned with why these string corrections do not inflate the mass of the Higgs particle if there is no supersymmetry to protect it.

Dines and Abel calculated that because of the different symmetries of string theory, the so-called modulus invariance (Modular invariance), the correction of the string states of all energy in the infinite energy spectrum from infrared to ultraviolet will cancel each other in a reasonable way, thus keeping the Higgs mass and cosmological constants very small. The researchers point out that this correlation between low-energy and high-energy string states does not explain why the Higgs mass and Planck energy are so far away, but the difference is stable. Still, according to Craig, "it's a really good idea."

The new model represents more and more UV-IR hybrid ideas. Another perspective of Craig's research can be traced back to another 1999 paper by Nathan Seiberg, a famous theoretical physicist at the Princeton Institute for Advanced Studies (IAS), and two collaborators. They studied how the background magnetic field fills the space. To understand how the UV-IR mixing occurs here, imagine a pair of opposing charged particles attached to a spring, flying in space perpendicular to the magnetic field. When you increase the energy of the magnetic field, the charged particles accelerate the separation and stretch the spring. In this toy scene, higher energy corresponds to a longer distance.

Seeberg and his colleagues found that the UV correction in this case has a special property-it shows how the reductionist arrowhead rotates, and the infrared affects the UV energy scale. This model is different from the real world because the real universe does not have such a background magnetic field to exert direction. Nonetheless, Craig has been exploring whether a similar approach can be used to solve the hierarchy problem.

Craig, Garcia and Seth Koren also jointly studied an idea about quantum gravity, called the weak Gravity conjecture (Weak gravity conjecture,WGC), which, if proved correct, may impose consistency conditions on the question of order-making a huge separation between the Higgs mass and the Planck scale necessary.

Dubowski of New York University has been thinking about these questions since 2013, when it was known that supersymmetric particles were delayed in the large Hadron Collider. That year, he and two collaborators discovered a new model of quantum gravity [4], which solved the problem of hierarchy. In their model, the arrow of reductionism points from the intermediate scale to both the ultraviolet and infrared scales. Although the results are interesting, the model only applies to two-dimensional space, and Dubowski does not know how to popularize it. Then he turned to other issues. Last year, he encountered the UV-IR hybrid problem again: in the study of colliding black holes, he found that the natural problem can be solved by "hidden" symmetry, which is related to the low and high frequencies of black hole deformation [5].

Like other researchers, Dubowski doesn't seem to think that any particular model found so far has an obvious Kuhn revolution. Some people think that the whole concept of UV-IR mixing is not promising. "there is no sign of the failure of effective field theory at present." "I don't think it's there," said David E. Kaplan, a theoretical physicist at Johns Hopkins University (who has nothing to do with the author of the CKN paper). Convincing ideas require experimental evidence, but so far, existing UV-IR hybrid models lack experimental predictions; they aim to explain why we don't see new particles outside the standard model. instead of predicting what we should see. However, for the prediction and discovery of new physics, even if it cannot be realized in the Collider, there is hope for the future in cosmology.

Taken together, the new UV-IR hybrid model illustrates the shortsightedness of the old paradigm based on reductionism and effective field theory, which may be just the beginning.

"in fact, when you enter the Planck scale, reductionism fails, so gravity is anti-reductionist." "I think, in a sense, it would be unfortunate if this fact had no profound implications for what we observed," Dubowski said. "

Annotation

[1] https://journals.aps.org/prd/abstract/10.1103/PhysRevD.14.1667

[2] https://journals.aps.org/prd/abstract/10.1103/PhysRevD.10.897

[3] https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.82.4971

[4] https://arxiv.org/abs/1305.6939

[5] https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.127.101101

This article is translated from Natalie Wolchover, A Deepening Crisis Forces Physicists to Rethink Structure of Nature's Laws

Original text link:

Https://www.quantamagazine.org/crisis-in-particle-physics-forces-a-rethink-of-what-is-natural-20220301/

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