Can the fabric of space-time to be with flaws?

The biggest lesson of the General theory of relativity is that space itself is not flat, unchanging and absolute being. It is woven together over time into a single fabric: space-time. This fabric is continuous, smooth and curved and becomes deformed in the presence of matter and energy. Everything that exists in this space-time moves along the path defined by the curvature of space-time and its movement is limited by the speed of light. But what if the fabric itself will be defective? This is not science fiction, but really, the current idea in theoretical physics. It is associated with high-energy relics like domain walls, cosmic strings and monopoles. Ethan Siegel from Medium.com tried to answer the question, what can be their origin, properties and how they will get along with the normal Universe.

Get a defective Universe, as it turned out, mathematically, is not so difficult.

the Gravitational behavior of the Earth's orbit is not due to invisible gravitational attraction, and it is better described by the Earth, freely falling through curved space in the presence of the Sun. Even in this case, the curvature of space is too small and no defects

Try to imagine the space as best as possible. What's it like? Will it be empty, is smooth and for the most part homogeneous? Do you also think that the only deviation from this condition will be associated with the presence of mass and quanta of energy? This is a good approach which usually choose physics. On large scales, the space will present a three-dimensional grid, the only deviations in which small regions of the spatial curvature of a small magnitude, creating a gravitational force, which we know well. Space in this configuration will be in a state of least energy.

the Fabric of space-time ripples and deformations because of the weight. As far as we know, the space never develops itself in itself, and not bent

But what about excited States? Or other? To make it easier, let's subtract two spatial dimensions and leave one thing: the line. The line can be direct, open and infinite or closed like a noose. In both cases, they are lines in a state of least energy. What would be the state of high energy? Imagine that you take your line and hang it as a string. Now do the string knot, like tying my shoelaces. String without a knot will be a one-dimensional space in the lowest energy state; a string with one node will represent a one-dimensional space in the first excited state. This node is 0-dimensional topological defect.

Now you can do interesting things with the node line. You can tie another knot the same way and to the two topological defect instead of one. But if you tie a knot in the opposite direction (that is, make the same loop, but otherwise let the ends of the cross before you throw and tighten), this node is topologically opposite to the original node. If you very carefully align both of the nodule (original opposite), it turns out that they can untie each other and return the line to a state of low energy.

Two types of these mixing effects node and antiuser — have a physical analogy in our Universe, magnetic monopoles. The node corresponds to an isolated North magnetic pole; antisal — isolated magnetic South pole. If you combine them, they annihilate like matter and antimatter, and return the fabric of space-time in a low energy state. As Monopoli is just a point particle, they will behave like ordinary matter, not much different from electric monopoles (positive and negative electric charges) in the Universe.

the Concept of a magnetic monopole emitting magnetic field lines as well as insulated electrical charge is emitted if the lines of electric field

So, let's return to our three-dimensional Universe. Now can imagine not only point defects but also vysokonapornye defects:

the
• Cosmic strings: when a one-dimensional line in some way permeates the entire observable Universe
the
• of Domain wall: when a two-dimensional plane with different properties from one side to the other passes through the Universe
the
• Space texture: when the area of three-dimensional space is twisted in knots

So we have monopoles (0-dimensional), strings (1-dimensional), wall (2-dimensional) and textures (3-dimensional) — all sorts of defects that arise from different arrangements of the same class: when the symmetry is broken.

the Differences between Universes, one created in accordance with the standard cosmology (left) and one created with a significant network of topological defects (right), issued a variety of large-scale structures. Our observation enough to rule out cosmic strings and domain walls as the dominant component of the modern Universe

Symmetry breaking is serious business in physics. Each existing symmetry correspond to the stored value, so if the symmetry is broken, this value is no longer saved. It is possible to produce Monopoli, in violation of spherical symmetry; it is possible to produce the strings, disturbing the angular or cylindrical symmetry; the violation of the discrete symmetry could generate a domain wall. Other defects are a bit harder to find, but they often come into play when it comes to scenarios with extra dimensions. But the first three — in particular, monopoles, cosmic strings and domain walls — are of particular interest for cosmology.

We know that the Standard model is not limited and there are many extensions and add-ons, which may have interesting observable consequences. One of them is the idea of Grand unification, when the electromagnetic, weak and strong nuclear forces unite at high energies. The idea of unification is that all three forces of the Standard model, and perhaps even gravity at high energies could be combined into a single structure. This not only would lead to the emergence of new particles and interactions, but would appear to magnetic monopoles. The lack of magnetic monopoles in the observable Universe is often cited as proof of cosmic inflation and the fact that the universe will never become hot enough after the end of inflation, to restore the symmetry of Grand unification Theories.

If the symmetry that allows the Great Association was broken, there would be a tremendous amount of magnetic monopoles. But in our Universe they do not exist; if cosmic inflation occurred after this symmetry was broken, at least one monopole were to remain within the observable Universe

Cosmic strings and domain walls would appear at phase transitions, if it really existed, shortly after the end of inflation. There may be some extremely high-energy symmetry, formed in the early times, breach of which appear similar defects. Cosmic strings and domain walls — one or a whole network — would need to leave a signature in the large scale structure of the Universe, the textures would appear in the CMB, and the monopoles to be created in the course of direct experiments. Some physicists point to the magnetic monopole, outdoor February 14, 1982, as proof of cosmic inflation: there is one monopole in the observable Universe, and we saw him!

In 1982, the experiment under the direction of Blas Cabrera, armed with eight turns of wire, filed the change of flow eight magnetons: indications pointing to the magnetic monopole. Unfortunately, at the time of detection there was nobody around and no one was able to reproduce the result, as well as to find another monopole

And if the monopoles behave as matter, cosmic strings, domain walls or cosmological texture will seriously affect the expansion of the Universe. Cosmic strings would behave as a spatial curvature, limiting the range of about 0.4% of the total energy density and domain wall will create a form of dark energy which slowly accelerates the expansion of the Universe that even you cannot ignore. Cosmological textures will have the same effect as a cosmological constant, but our observable universe must be confined to a single defect in order to explain our observations.

Various components of the energy density of the Universe and when they could emerge in full force. If cosmic strings or domain walls existed at least in some quantity, they would seriously affect the expansion of our Universe

The Monopoles, strings, walls, textures and other defects should be heavy, if it existed. Monopoles would be the most massive particle discovered (in 100 trillion times more massive than the top quark). Strings, walls, and textures become seeds for the large-scale structure, pulling together matter and forming other structures that we easily would be discerned with the aid of modern telescopes, surveys and CMB data. Current limits tell us that such structures do not exist in abundance, and they hardly had more than a few percent of the total energy budget of the cosmos.

To date, there is no evidence that our universe is defective, except a single observation of a magnetic monopole 35 years ago. Although we can't disprove their existence (only limit), you need to keep my ears open and be ready not only to their possible detection, but also to any other additions to the Standard model, is not prohibited by physics. In most cases,...