Questions tagged [cosmic-string]
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11
questions
1
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1answer
36 views
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 ...
2
votes
1answer
135 views
What's the connection between cosmic strings and the strings hypothesized in string theory?
I read somewhere that Edward Witten, the (once) big hotshot of string theory, said that the discovery of cosmic strings (at the beginning of this Wikipedia article it is written: "Not to be confused ...
1
vote
1answer
143 views
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, ...
0
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1answer
57 views
I've read a cosmic string can accelerate a mass. Can someone explain how it works?
In the book Brief Answers to the Big Questions: the final book from Stephen Hawking Hawking describes cosmic strings as follows;
They are like rubber bands as they are under great tension, ...
3
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0answers
29 views
Candidates for cosmic strings
What are the observed candidates for cosmic strings (or other defects), that are not ruled out? With references if possible.
1
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0answers
77 views
Black hole and the cosmic string
For a regular black hole, the mass and energy of the black hole are identical（according to first law of black hole thermodynamics), but for a black hole with a cosmic string this is not satisfied. ...
3
votes
0answers
68 views
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 ...
5
votes
1answer
124 views
Gravitational lensing and cosmic strings
Say we have a straight cosmic string lying along the $z$-axis, with energy-momentum tensor
$$T_{\mu\nu}=\mu\delta(x)\delta(y)\operatorname{diag}(1,0,0,-1)\tag{1}\label{1}$$
for some small positive ...
2
votes
1answer
145 views
Kalb-Ramond action and topological string radiation
Let's have simple scalar $\Phi$ action involves spontaneously symmetry breaking in a form
$$
\tag 1 S = \int d^{4}x\left( |\partial_{\mu}\psi|^{2} + \psi^{2}|\partial_{\mu}\theta |^{2} - \frac{\lambda}...
1
vote
1answer
84 views
Global cosmic strings evolution
Recently I've read about axion string. It can be shown that the energy per unit length of the string located along $z$ axis is
$$
\mu = 2 \pi f_{a}^{2}\ln\left( \frac{L}{\delta}\right),
$$
where $L$ ...
0
votes
2answers
173 views
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 ...
