Questions tagged [cosmic-string]
Questions about properties, dynamics and phenomenology of cosmic strings and superstrings.
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What is the tension for a cosmic string formed at the electroweak scale?
Cosmic strings are characterized by their dimensionless tension, $G\mu$. Their mass per unit length $\mu$ is given by the square of the energy scale of their formation. For strings formed at the ...
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Is the spinning Cosmic String spacetime totally vicious?
The spacetime $(M,g)$ is given locally at each point by the metric:
$$g= -(dt + a \, d \phi)^2 + d\rho^2 + \kappa^2 \rho^2 \, d\phi^2 + dz^2 \ \text{where} \ \ a > 0$$
This is the spacetime of a ...
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The Lebesgue covering dimension of the Cosmic String interval topology
Take the spacetime $(M,g)$ that satisfies Einstein's Field Equations exactly where $g$ is locally:
$$g= - c^2 dt^2 + d \rho^2 + (\kappa^2 \rho^2 - a^2) d \phi^2 - 2 ac d\phi dt + dz^2 \ $$
in the ...
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Cosmic string in real space
I am considering $U(1)$ global cosmic string.
In the case of wine-bottle potential with real field ($\phi$), it is known that there exists a static solution that corresponds to cosmic string (or ...
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Could inhomogeneties and/or topological defects break the fundamental symmetries of the universe?
I have heard that some types of inhomogeneties and topological defects (like cosmic strings) in cosmology have been proposed to be able to break fundamental symmetries of nature such as the Poincaré, ...
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How does the Higgs field energy state relate to the tension of a Cosmic String?
I understand these cracks are massless objects, but if a string has an apparent mass from its warping of spacetime, how does this relate to the higher energy value of the Higgs field the Cosmic String ...
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What if a cosmic string is eaten by two black holes?
What happens if you have a long cosmic string, each end of which is swallowed by a different blackhole, and the black holes have trajectories that will take them further away from eachother?
WHat ...
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Using a stress-energy tensor in linearized Einstein equations
I am using a known stress-energy tensor to try to find $h_{\mu\nu}$, the small deviations from flat space in the linearized Einstein formalism. In harmonic gauge,
$$
\square h_{\mu\nu}=-16\pi GT_{\mu\...
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Could Gott's Cosmic String Time Machine hypothetically be used as a poor man's Alcubierre drive?
I have read much speculation about Gott's theoretical use of cosmic strings for time travel, but if the colliding cosmic strings accelerated the spacecraft faster than light, as Gott theorizes, could ...
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Tension of a String
does anybody know a general relation between the tension of a string and it's energy density? I am at the moment learning about topological cosmic strings and calculated the energy density, now I do ...
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How does a Cosmic String accelerate a Black Hole?
I've read that a Cosmic String could accelerate a Black Hole, but I'm not exactly sure how that works. Is the Black Hole pulled along the length of the String? I've also heard it could accelerate ...
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Circling a Cosmic string in less than 360 degrees for faster space travel?
I've red that Cosmic strings would warp space such that one could circle a cosmic string in less than 360 degrees. How few degrees?
If a ship were to circle a cosmic string in a spiral pattern, saving ...
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Spacetime with a point defect
What is the metric for a spacetime with a point defect? Spacetime metric with line defects are well-known, they are basically Cosmic strings. Is anyone aware of an example for spacetime with point ...
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Schwarzschild with cosmic strings: How can I visualize the string?
Geometrically, you can talk about a cosmic string in Schwarzschild black hole with this metric $[1]$:
$$ds^{2} = -\Big(1- \frac{r_{s}}{r}\Big) dt^{2} + \frac{1}{\Big(1- \frac{r_{s}}{r}\Big)}dr^{2} + ...
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Gravitational attraction/repulsion of cosmic strings and domain walls
It is well known that straight static cosmic strings don't produce any gravitational effects on test-particles, and that static flat domain walls are repulsive. This can be seen from the linearized ...
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What are the two different $\mathbb{S}^n$ in the construction of the homotopy group $\pi_n(\mathbb{S}^n)$ that classifies topological defects?
According to Mukhanov's Physical Foundations of Cosmology,
Homotopy groups give us a useful unifying description of topological defects. Maps of the $n$-dimensional sphere $\mathbb{S}^n$ into a ...
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How to create a cosmic string?
I know about cosmic strings. They are 1-D topological defects in space-time which may had been created during the symmetry breaking phase transition during the big bang. But my question is : Are ...
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Does Goldstone theorem have anything to do with Cosmic string
Cosmic strings are formed due to topological defects during symmetry breaking phase transition in early universe.
While Goldstone theorem states whenever we have continuous symmetry and it is ...
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Cosmic strings and ground state degeneracy in SSB
There are two conflicting perceptions that I have regarding the notion of ground state post-SSB. Consider the Higgs mechanism e.g. for the electroweak theory.
On the one hand, we say that the vacuum ...
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What is a String Wall?
This question has nothing to do with sound waves, physical strings or walls...
I am reading: https://arxiv.org/abs/1709.07091
It states
"In the post-inflationary PQ symmetry breaking scenario, ...
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Candidates for cosmic strings
What are the observed candidates for cosmic strings (or other defects), that are not ruled out? With references if possible.
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Basic question on Cosmic Strings
What is the typical size of Cosmic String Loops?
If a loop is formed today, what are the restrictions on its size?
I would like to know if there is a distribution of cosmic strings depending on its ...
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Kalb-Ramond action and topological string radiation
Let's have simple scalar $\Phi$ action involves spontaneously symmetry breaking in a form
$$
\tag 1 S = \int d^{4}x\left( |\partial_{\mu}\psi|^{2} + \psi^{2}|\partial_{\mu}\theta |^{2} - \frac{\lambda}...
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Cosmic string & grandfather paradox
Cosmic string was proposed several decades ago and there are claims stating it can span across the length of the universe and is less than an atom thick. How does a broken pieces of these cosmic ...
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