Is the other article you are reading exactly the same as this one? That guy is not himself, but lives in a misty mountain range, endless fields, noisy cities, and revolves around a star with eight other planets, and is also called "Earth"? His (her) life experience is the same as yours every second. However, maybe at this moment she is about to put the article down and you are about to read it.
This idea of ??"being in two places at the same time" sounds strange and unbelievable, but it seems that we have to accept it because it is supported by various astronomical observations. The most popular and simplest model of the universe now states that there is a galaxy exactly like our Milky Way about 10 (10 28) meters away from us, and there is a galaxy exactly like you inside. Although this distance is beyond people's imagination, it does not affect the authenticity of your "doppelg?nger". The idea originally stemmed from a very simple "natural possibility" rather than the assumptions of modern physics: the size of the universe is infinite (or at least large enough), and matter is evenly distributed, as astronomical observations indicate . In this case, according to statistical laws, it can be concluded that all events (no matter how similar or identical) will happen countless times: there will be countless planets that give birth to humans, and among them there will be people exactly like you - looking like , names, memories and even actions and choices are exactly the same - and there will be more than one such person, to be precise, there are infinite ones.
2. Bubble theory
The term "bubble state" casually refers to the sudden increase in price of one or a series of assets in a continuous process. An initial price increase creates expectations of a price increase, which in turn attracts new buyers. These people generally only want to profit from trading and are not interested in the purpose of the assets themselves and their ability to generate profits. Price increases are often followed by a reversal of expectations, followed by a sharp fall in prices, culminating in a financial crisis. Typically, "booms" last longer than bubble conditions, with more modest increases in prices, output, and profits. In the future, it may end in a crisis in the form of a crash (or panic), or it may end in a gradual decline in prosperity without a crisis.
Gindl Borg's definition of bubble is very vivid, but it is difficult to operate in theoretical research. Modern economic research typically defines a bubble as a sustained deviation of asset prices from their fundamental value. This definition simplifies the judgment of bubbles. There are two tasks to be done. One is to determine the basic value of the asset, and the other is to see whether the deviation in the asset price continues or disappears in a short period of time.
Postscript
[Popular Science] Parallel Universe (Full Text Ended) (Updating)
Original text: (US) Max Tmark
Original text: "Scientific American", May 2003.
Translation: Focus
Parallel Universe
Is the other article you are reading exactly the same as this one? That guy is not himself, but lives in a misty mountain range, endless fields, noisy cities, and revolves around a star with eight other planets, and is also called "Earth"? His (her) life experience is the same as yours every second. However, maybe at this moment she is about to put the article down and you are about to read it.
This idea of ??"being in two places at the same time" sounds strange and unbelievable, but it seems that we have to accept it because it is supported by various astronomical observations. The most popular and simplest model of the universe now states that there is a galaxy exactly like our Milky Way about 10 (10 28) meters away from us, and there is a galaxy exactly like you inside. Although this distance is beyond people's imagination, it does not affect the authenticity of your "doppelg?nger". The idea originally stemmed from a very simple "natural possibility" rather than the assumptions of modern physics: the size of the universe is infinite (or at least large enough), and matter is evenly distributed, as astronomical observations indicate .
In this case, according to statistical laws, it can be concluded that all events (no matter how similar or identical) will happen countless times: there will be countless planets that give birth to humans, and among them there will be people exactly like you - looking like , names, memories and even actions and choices are exactly the same - and there will be more than one such person, to be precise, there are infinite ones.
The latest cosmological observations show that the concept of parallel universes
is not a metaphor. Space seems infinite. If so,
everything that can happen is destined to happen, no matter what they are
how ridiculous. In places where we cannot observe astronomy.
Fang, there is a universe exactly like ours. Astronomers have even calculated
to find out their average distance from Earth.
You may never see your "shadow". The farthest distance you can observe is the farthest distance that light has traveled since the Big Bang: approximately 654.3804 billion light-years, which is 4X10^26 meters - a radius that just defines the size of our observable horizon. The size of the sphere, or simply the universe, is also called the Hubble volume. Similarly, the other universe you live in is also a sphere of the same size. The above is the most intuitive explanation of "parallel universe". Each universe is a small part of the larger "multiverse".
With such a definition of "universe" one might think that this is just a metaphysical approach. However, the difference between physics and metaphysics is whether the theory can be tested experimentally, not whether it looks weird or contains something difficult to detect. Over the years, the frontiers of physics have continued to expand, absorbing and incorporating many abstract (even metaphysical) concepts, such as a spherical Earth, invisible electromagnetic fields, the rapid and slow flow of time, quantum overlap, the curvature of space, black holes, and more. In recent years, the concept of the "multiverse" has been added to the above list, and it joins some previously tested theories such as relativity and quantum mechanics to achieve at least one basic criterion of an empirical scientific theory: making predictions. Of course, the conclusions drawn may also be wrong. So far, scientists have discussed as many as four types of independent parallel universes. What matters now is not the existence of multiverses, but how many levels they have.
The First Level: Beyond the Horizon
All parallel universes make up the first multiverse. - This is the least controversial layer. Everyone accepts the fact that although we cannot see another self at the moment, we can observe it in another place, or simply wait in the same place for a long time. It's like observing a ship coming from above sea level - observing an object beyond the horizon is similar. As light travels, the radius of the observable universe expands by one light-year every year, and you just have to sit there and watch. Of course, you may not wait for the day when light from another universe reaches here, but in theory, if the theory of cosmic expansion holds true, your descendants might be able to see them with super telescopes.
How about it, the concept of the first layer of the multiverse sounds unremarkable? Isn't space infinite? Who could have imagined that there was a sign somewhere that said "Space ends, watch out for the ditch below"? If this is the case, everyone will instinctively question: What is "outside"? In fact, Einstein's gravitational field theory has turned our intuition into a problem. Space may not be infinite as long as it has a certain curvature or is not topological as we intuitively think of it (i.e. has an interconnected structure).
A spherical, donut-shaped, or trumpet-shaped universe may have a finite size, but it has no boundaries. Observations of the cosmic microwave background radiation can be used to test these hypotheses. See also the article, Is the Universe Finite? ” by Jean-Pierre Luminet, Glenn D. Starkman, Jeffrey R. Weeks; Scientific American, April 1999 However, observations to date appear to be inconsistent with contradiction. The model of the infinite universe is consistent with observational data, with strong constraints.
Another possibility is that space itself is infinite, but all matter is confined to a finite area around us - the once popular "island universe" model.
What's different about this model is that matter is distributed in fractal patterns on large scales and is constantly dissipated. In this case, almost every universe in the first multiverse would eventually become empty and fall into silence. However, recent observations of three-dimensional galaxy distribution and microwave backgrounds have shown that the organization of matter exhibits some fuzzy uniformity on large scales, and clear details cannot be observed on scales larger than 10 24 meters. Assuming this pattern continues, the space beyond the Hubble Volume will also be filled with planets, stars, and galaxies.
There is data to support the theory that space extends beyond the observable universe. The WMAP satellite recently measured fluctuations in the microwave background radiation (left). The strongest amplitude exceeds 0.5 kHz, implying that the space is very large, even infinite (middle picture). In addition, the WMAP and 2dF galaxy redshift detectors found that matter is evenly distributed in space at very large scales.
Observers living in different parallel universes of the first multiverse will perceive the same physical laws as us, but with different initial conditions. According to the current theory, matter was thrown out with a certain degree of randomness in the early stages of the Big Bang, and this process includes all possibilities for the distribution of matter, and each possibility is non-zero. Cosmologists assume that our universe, with its approximately uniform distribution of matter and initial wave state (one of 100,000 possibilities), is a fairly typical (at least typical of all parallel universes that have produced observers) individual . Then the nearest person who is exactly like you will be 10 (10 28) meters away; only 10 (10 92) meters away will there be an area with a radius of 100 light years, and everything in it will be the same as the space we live in Exactly the same, that is to say, everything that happens in our world in the next 100 years will be completely reproduced in this area; at least 10 (10 118) meters away, the area will increase to the size of Hubble. In other words, it will There is a universe exactly like ours.
The above estimates are extremely conservative. It enumerates only one Hubble volume, all quantum states of space with a temperature below 10 8 Kelvin. One step of the calculation goes like this: At that temperature, how many protons can a Hubble volume hold at most? The answer is 10 118. Each proton may or may not exist, that is, there are * * * 2 (10 118) possible states. Now you only need a box that can hold 2 Hubble spaces (10 118), and all possibilities are exhausted. If the box were larger—say, a box with side lengths of 10 (10 118) meters—the arrangement of protons would inevitably repeat according to the pigeon hole principle. Of course, the universe is not just protons, but also has more than two quantum states, but the total amount of information the universe can hold can also be estimated using a similar method.
The average distance to another universe exactly like ours.
The nearest "doppelg?nger" may not be as far away as theoretical calculations, but it may also be much closer. Because the organization of matter is also restricted by other physical laws. Given some laws such as planet formation processes and chemical equations, astronomers suspect that there are at least 10 20 inhabited planets in our Hubble volume alone. Some of them may be very similar to Earth.
The first multiverse framework is often used to evaluate modern cosmological theories, although this process is rarely articulated. For example, let's examine how our cosmologists try to map the geometry of the universe in "spherical space" through the microwave background. With the difference in the radius of curvature of space, the size of the "hot areas" and "cold areas" on the cosmic microwave background map will show some characteristics; the observation area shows that the curvature is too small to form a spherical closed space. However, it is important to maintain statistical rigor. The average size of these regions in each Hubble space is completely random. So it is possible that the universe is fooling us - it is not that the curvature of space is not enough to form a closed sphere, making the observed area very small, but just because the average area of ??our universe is naturally smaller than others.
So when cosmologists swear that their spherical space model is 99.9 reliable, what they really mean is that our universe is so unsociable that only one in 1,000 Hubble volumes would be like that.
The point of this lesson is: even if we cannot observe other universes, the multiverse theory can still be verified in practice. The key is to predict the * * * of each parallel universe in the first multiverse and indicate its probability distribution - what mathematicians call a "measurement". Our universe should be one of those "most likely universes." Otherwise - and unfortunately we live in an unlikely universe - then the previously hypothesized theory would be in big trouble. As we will discuss next, how to solve this measurement problem becomes quite challenging.
Schematic diagram of the second layer of the multiverse.
Second level: bubbles left after expansion.
If the concept of the first-level multiverse is not easy to digest, you can try to imagine the structure of an infinite group of the next first-level multiverse: the groups are independent of each other and even have different space-time dimensions and physical constants . These groups constitute the second multiverse—predicted by modern theory as "disorderly expansion."
As an inevitable extension of the Big Bang theory, "inflation" is closely related to many other corollaries of the theory. For example, why is our universe so large and regular, smooth and flat? The answer is that "space has undergone a rapid stretching process", which can not only explain the above problems, but also explain many other properties of the universe. See "The Inflating Universe" by Alan H. Guth and Paul J. Steinhard; Scientific American, May 1984; "The Inflation" by Andre Linder, "The Inflation" by Self-Propagating Expanding Universe, November 1994 The theory is not only stated by many elementary particle theories, but also confirmed by many observations. "Continued disorder" refers to behavior on the largest scale. The space as a whole is being stretched and will continue to do so forever. But certain areas stop pulling, creating individual "bubbles," like those inside puffed up toast. There are countless such bubbles. Each of them is the first multiverse: infinite in size, filled with matter precipitated by fluctuations in energy fields.
For the earth, the other bubble is infinitely far away, so far that you can never reach it even if you travel at the speed of light. Because the space between Earth and "the other bubble" stretches far faster than you can travel. If there was another you in another bubble, even your descendants would never think of observing him. For the same reason, that is, the expansion of space is accelerating, the observation results are frustrating: not even the other self in the first multi-space can be seen.
The second level of the multiverse is very different from the first level. Not only are the initial conditions different between bubbles, but their appearance is also different. The current mainstream view in physics is that the dimensions of time and space, the properties of elementary particles, and many so-called physical constants are not part of the basic laws of physics, but are simply the result of a process called "symmetry breaking." For example, theoretical physicists believe that our universe once consisted of nine equal dimensions. In the early history of the universe, only three dimensions participated in the pull of space, forming the three-dimensional universe we observe now. The other six dimensions are now unobservable because they are curled up on a very small scale, with all matter spread across the three fully stretched "surfaces" (which, to the ninth dimension, is just one surface, or a "membrane").
It is not particularly surprising to us that we live in 31-dimensional space-time. When describing nature
When the partial differential equation is an elliptic or hyperbolic equation, that is, one of space or time is 0-dimensional or
At the same time, it is impossible for the observer to predict the universe ( purple and green parts).
In other cases (hyperbolic equations), if n > 3. Atoms cannot exist stably, n
As for observers who cannot produce self-awareness (no gravity, topological structure is also a problem).
From this, we say that the symmetry of space is destroyed.
The uncertainty in quantum waves causes different bubbles to disrupt their equilibrium in different ways as they expand. And the results can be weird. Some of these may extend into four dimensions; others may form only two generations of quarks instead of the three we know of; and some of the universe's fundamental physical constants may be larger than ours.
Another way to create a second multiverse is to go through the full cycle of universes from creation to destruction. In the history of science, this theory was proposed in the 1930s by a physicist named Richard C. Recently, two scientists, Paul J. Steinhardt of Princeton University and Neil Turok of the University of Cambridge, elaborated on this. Steinhardt and Turok proposed a model of a "secondary three-dimensional brane" that is fairly close to our space, but with some translation in higher dimensions. See “Been There, Done That,” by George Musser; News Scan Scientific American March 2002 Parallel universes are not really independent universes, but the universe as a whole—past, present, future— — formed a multiverse that could prove to contain as much diversity as the disorderly expansion of the universe. Additionally, Waterloo physicist Lee Smolin has proposed another theory with similar diversity to the second multiverse, in which the universe is created and mutated through black holes rather than through membrane physics.
Although we cannot interact with other things in the second multiverse, cosmologists can indirectly point to their existence. Because their existence can be used to explain the randomness of our universe. An analogy: Suppose you walk into a hotel and find a room with the house number 1967, which is the year you were born. What a coincidence! At that moment you were stunned. But your immediate reaction is no coincidence. There are hundreds of rooms in the entire hotel, and it’s normal for one of them to be the same as your birthday. But if you see another number that has nothing to do with you, it won't trigger the above thoughts. What does this mean? Even if you know nothing about hotels, you can use the above method to explain many accidental phenomena.
To give another more pertinent example: examine the mass of the sun. The mass of the sun determines its luminosity (i.e., the total amount of radiation). Through basic physical calculations, we know that only when the mass of the sun is within a narrow range of 1.6x 10 30 ~ 2.4x 10 30 kilograms, can the earth be suitable for life. Otherwise the Earth would be hotter than Venus, or colder than Mars. The mass of the sun is exactly 2.0x10^30 30 kilograms. At first glance, the Sun's mass appears to be an astonishing case of luck and coincidence. The masses of most stars are randomly distributed in the huge range of 10 29 ~ 10 32kg, so if the mass of the Sun is randomly determined at birth, the chance of falling within the appropriate range will be very small. However, with the experience of the hotel, we understand that this superficial accident is actually the inevitable result of a large system (here refers to many solar systems) (because we are here, the mass of the sun has to be like this). This observer-dependent selection is known as the "anthropic principle." Although it's understandable how controversial it has been, physicists have widely accepted that this selection effect cannot be ignored when testing fundamental theories.
What applies to hotel rooms also applies to parallel universes. Interestingly, when the symmetry of our universe is broken, all (at least most) properties are "tuned" just right. If we made even the slightest change to these properties, the entire universe would be unrecognizable—no living thing could survive in it. If the mass of a proton increases by 0.2, it immediately decays into a neutron, and the atom cannot exist stably. If the electromagnetic force were reduced by 4, there would be no hydrogen and no stars. If the weak interaction were weaker, hydrogen could not form either. On the contrary, if they were stronger, those supernovae would not be able to transmit heavy element ions to the star. If the cosmological constant is large, it will blow itself apart before galaxies form.
While the jury is still out on how well-tuned the universe is, each of the examples mentioned above implies that there are many parallel universes containing every possible tuning state. See "Exploring Our Universe and Beyond" by Martin Rees; Scientific American, December 1999. The second multiverse shows that it is impossible for physicists to determine the theoretical values ??of those constants. They could only calculate the probability distribution of expected values ??after accounting for selection effects.
The Third Level: Quantum Parallel Worlds
The parallel worlds predicted by the first and second multiverses are far apart and cannot be reached by astronomers. But the next multiverse is around you and me. It comes directly from the famous and controversial interpretation of quantum mechanics - that any random quantum process causes the universe to break into parts, each part representing a possibility.
Quantum parallel universe. When you roll a dice, it seems to randomly get a specific result. However, quantum mechanics states that the moment
you actually roll each state, the dice comes to rest at a different point in the different universes. One universe, you throw 1, another.
In universe, you roll a 2. But we can only see a small part of the whole truth - one of the universes.
At the beginning of the 20th century, the success of quantum mechanics theory in explaining atomic phenomena set off a revolution in physics. In the atomic realm, the motion of matter no longer obeys the classical laws of Newtonian mechanics. While quantum theory explained their extraordinary success, it sparked an explosive and heated debate. What exactly does this mean? Quantum theory states that the universe is not as classical theory describes it. What determines the state of the universe is not the position and velocity of all particles, but a mathematical object called the wave function. According to the Schr?dinger equation, states evolve over time in a way that mathematicians call "unity," which means that the wave function evolves in an infinite-dimensional space called a "Hilbert space." Although quantum mechanics is described as stochastically uncertain most of the time, the evolution pattern of the wave function itself is completely deterministic and completely devoid of randomness.
The key question is how to relate the wave function to what we observe. Many reasonable wave functions lead to seemingly absurd and illogical states, such as a cat that is both dead and alive under so-called quantum superposition. In order to explain this strange situation, in the 1920s, physicists proposed a hypothesis that when someone attempts to observe it, the wave function immediately "collapses" into a certain state in classical theory. This additional assumption can solve the observed problems, but it makes the originally elegant and harmonious theory pieced together and loses its unity. The nature of randomness often attributed to quantum mechanics itself is the result of these unpalatable assumptions.
Many years later, physicists gradually abandoned this hypothesis and began to accept an idea proposed by Princeton University graduate Hugh Everett in 1957. He pointed out that the assumption of "collapse of the wave function" was completely unnecessary. Pure quantum theory actually produces no contradictions. It predicts that one real state will gradually split into many overlapping real states, and the subjective experience of the observer during the splitting process is just a slightly random event with a probability exactly equal to the previous "wave function collapse hypothesis". This overlapping traditional world is the third multiverse.
For more than 40 years, the physics community has hesitated several times to accept Everett's parallel world. But it would be easier to understand if it were broken down into different perspectives. Physicists who study its mathematical equations stand from an external perspective, like a bird flying in the air and inspecting the ground; observers living in the world described by the equations stand from an internal perspective, like a bird looking down on frog.
From the bird's perspective, the entire third multiverse is simple. It can be described by a smoothly evolving and deterministic wave function without causing any splits or parallels. The abstract quantum world described by this evolving wave function contains a large number of parallel classical worlds. They are splitting and merging all the time, like a bunch of quantum phenomena that cannot be described by classical theory. From the frog's perspective, the observer perceives only a small part of the total truth.
They could observe their first universe, but a function called "decoherence," which mimics the collapse of the wave function while preserving unity, prevented them from observing other parallel universes.
Every time an observer is asked a question, makes a decision, or answers a question, quantum interactions in his brain lead to compound outcomes such as "continue reading this article" and "give up Read this article”. From the bird's perspective, the act of "making a decision" causes the person to split into two, with one person continuing to read the article and the other doing other things. From the frog's perspective, neither of the person's two clones were aware of the other's existence, and their perception of the split was just a slight random event. They only know what decision they made, but they don't know that another "he" made a different decision at the same time.
As strange as it sounds, this kind of thing also happens in the first multiverse mentioned above. Obviously, you just made the decision to "continue reading this article," but in another galaxy far, far away, you put down the magazine after reading the first paragraph. The only difference between the first universe and the third universe is where the "other you" is. In the first universe, he was far away from you - usually "far" in the dimensional sense. In the third universe, your double lives in another quantum branch, separated by an infinite-dimensional Hilbert space.
The existence of the third multiverse is based on a crucial assumption: the unity of the wave function evolving over time. Fortunately, experiments to date have never deviated from the unity assumption. Over the past few decades, we have demonstrated unity in a variety of larger systems, including carbon 60 buckyballs and optical fibers up to several kilometers long. Instead, this unity is also supported by the discovery of "decoherence." See "100 Years of Quantum Mysteries" by Max Tegmark and John Archibald Wheeler; Scientific American February 2006 5438 0 Only some theoretical physicists in the field of quantum gravity question unification sex. One view is that evaporating black holes may destroy unity, and it should be a non-unified process. However, a recent string theory study called "AdS/CFT consistency" suggests that the quantum gravitational field is also unified and that black holes do not erase information but transmit it elsewhere.
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If physics is unified, the standard picture of how quantum waves worked in the early days of the Big Bang will have to be rewritten. Instead of randomly generating one initial condition, they generate all possible initial conditions that overlap and exist simultaneously. "Decoherence" then ensures that they evolve in their respective quantum branches just like traditional theory. This is the key point: the distribution results of different quantum branches (the third level multiverse) in one Hubble volume are no different from the distribution results of the same quantum branch (the first level multiverse) in different Hubble volumes. This property of quantum waves is called ergodicity in statistical mechanics.
The same principle can be applied to the second multiverse. The process of breaking symmetry produces not just a single outcome, but a superposition of all possible outcomes. These results then move in their own direction. Therefore, if the physical constants and space-time dimensions are different in the quantum branches of the third-level multiverse, then the second-level parallel universe will also be different.
In other words, the third multiverse does not add anything new to the first and second layers, they are just more difficult-to-distinguish copies - the same old story with different quantum Played out over and over again in branching parallel universes. The once intense skepticism about Everett's theory disappeared after everyone discovered that it was essentially the same as other, less controversial theories.
Schematic diagram of the difference between the third layer and the first layer
There is no doubt that this connection is quite profound, and physicists’ research has just begun. For example, consider a long-standing question: Will the number of universes grow exponentially over time? The answer is surprisingly "no."
For birds, the entire world is described by a single wave function; for frog, the number of universes cannot exceed the total number of all distinguishable states at a given moment - that is, the Hubble volume containing different states total number. For example, the planet moves to a new position, marrying someone or something else, these are all new states. Below the threshold temperature of 10 8, the total number of these quantum states is about 10 (10 118), which means there are at most this many parallel universes. That's a huge number, but it's very limited.
From the perspective of a frog, the evolution of the wave function is equivalent to jumping from one universe to another in 10 (10 1118). Now you are in universe A - the universe in which you are reading this sentence at this moment. Now you jump into universe B - you are reading another sentence in that universe. There is an observer in universe B that is exactly the same as universe A, with only a few seconds more memory. All possible states exist at every moment. Therefore, the "passage of time" is likely to be the transition process between these states - it was first proposed by Greg Egan in his 1994 science fiction novel "Aligning Cities" and later proposed by Oxford University Physics Co-published by author David Deutsch and freelance physicist Julian Barber.