Max Tegmark, a cosmologist at MIT, is keen on studying parallel universes. He said, "The question I am most interested in is not whether there are parallel universes, but how many kinds of parallel universes there are." In Scientific American magazine in 2003, there was a special article about parallel universes written by him. He divided parallel universes into four categories. According to Temak's classification, the higher the universe, the easier it is to expand and cover the lower-level universe.
The first floor: beyond the horizon
If space is infinite and the distribution of matter is uniform enough on a large scale, even the most impossible thing will happen somewhere. In particular, there should be an infinite number of people on the planet, including not one but an infinite number of people with the same appearance, name and memory. Hubble's infinite area does exist, and any possible history of the universe will actually exist. This is the first parallel universe.
Chaos inflation theory can make a general prediction for the infinite ergodic universe. This universe is infinite, and it should contain Hubble volume that can realize all initial conditions.
Therefore, the infinite universe contains infinite Hubble volumes. Although they all have the same physical laws and quantities, the distribution configuration of similar substances is almost different from the Hubble volume where people live. However, it is precisely because of the existence of Hubble volume that there is a Hubble volume outside the event horizon with similar results or the same configuration. According to the calculation of physical markers, stars with the same size, volume and configuration as human habitation exist at a distance of about 1 15 meters (more than the number of Gugor Plex). This inference assumes a distribution that looks like Hubble state, but what kind of distribution is actually possible. This means that a specific Hubble volume is actually unique.
The second layer: foam after inflation
As the chaotic expansion theory of the universe expansion theory, the parallel universe expands as a whole and this expansion will continue. But a certain area of the universe has stopped expanding, showing different bubble shapes. This bubble is the first undeveloped parallel universe. Andre Woodland and Vitaly Van Chulin calculated that the number of this universe is 10000000 units of measurement. It is possible that different bubbles have undergone primary symmetric rupture, resulting in different physical constants and different properties. This level includes john wheeler's oscillating universe theory and Lee smolin's prolific universe theory.
The third layer: Multi-world explanation in quantum mechanics.
Hugh? Everett's Multi-World Interpretation (MWI) is one of the mainstream explanations in quantum mechanics. As a side of quantum mechanics, it can't be absolutely predicted by a single observation. On the contrary, it may trigger different probabilities in a wider range. According to MWI theory, these different observations correspond to different universes. Just like shaking a six-sided dice, the result is consistent with the observable measurement of quantum mechanics. Six universes corresponding to the six faces of the dice are revealed. (More correctly, in MWI theory, although the existence of the universe is unitary, they usually can't interact with each other after being split into multiple worlds. )
Temak thinks that the content of the third parallel universe is not greater than the probability of the first and second parallel universes. In fact, in the third parallel universe with the same physical number, all the different worlds formed by splitting can be found in multiple Hubble volumes in the first parallel universe. Temak made the following statement: The only difference between the first floor and the third floor is where the human replica lives. On the first floor, live anywhere in three-dimensional space. On the third level, I live in an infinite world different from other quanta in Hilbert space. Similarly, all bubble universes with different second-order physical constants can also be regarded as "worlds" generated in the third-order parallel universe at the moment of primary symmetry breaking.
The viewpoints related to the pluralistic world include Feynman's explanation of multiple history and Zeh's explanation of multiple minds.
The fourth layer: the ultimate series
The ultimate set hypothesis was advocated by Temak himself. The universe that can be described by different mathematical structures is considered to actually exist in an equivalent way. No, hubble volume's different laws of low-energy physics are not included. Temak advocates the following views. Abstract mathematics is very common, and the general theory of everything (TOE), which can be defined in any pure language, cannot be separated from mathematical structure. For example, TOP, which contains different kinds of entities (expressed in language) and their relationships (expressed in language), is not only called a set theory model by mathematicians, but also usually regarded as a formal system. This means that all imaginable parallel universe theories can be described in four stages. Because level 4 parallel universe contains all other sets, it becomes the upper limit of parallel universe level. As a result, there is no room to consider a level 5 parallel universe.
You Ergen schmid and huber put forward different opinions, arguing that there is no clear definition of "mathematical structure set". He only agrees with structural mathematics, that is, the expression of the universe that can be described by computer programs. Among them, the output bit can be controlled in a limited time, and the control time itself can't be predicted because of the Kurt limit, but because of the non-stop program, the expression that can describe the universe is very clearly included. In addition, he raised clear objections to a relatively limited set of universes that can perform extremely fast operations.