Questions tagged [tachyon]
Tachyons are hypothetical particles with imaginary mass and they thus may move faster than light. However, their existence in a theory, indicates an unstable ground state.
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How would a tachyon gravitationally interact with a fermion? [closed]
Assuming that tachyons were real and we somehow managed to trap some, what would its gravitational field look like? I know they have imaginary mass, but I’m having a very hard time trying to figure ...
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Does Relativity really allow faster-than-light travel (for non-tachyons)? [closed]
10 Physics Myths You Probably Believe! - by Sabine Hossenfelder
In first place she has "faster than light travel is incompatible with Einstein's theories". The transcript of the video goes:
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What is the equation of state (EoS) of tachyonic particles?
In cosmology, the thermodynamical equation of state (EoS) of non-relativistic dust particles is $p = 0$, while the EoS of random photons is $p(\rho) = \tfrac{1}{3} \, \rho$ (ultra-relativistic ...
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If we imagine tachyonic particles do exist, then can they travel slower than the speed of light $c$ from a reference frame traveling slower than $c$?
If we imagine a tachyonic particle travelling faster than the speed of light, can there be any reference frame which perceives a tachyon as travelling slower than $c$ by applying Lorentz contraction? ...
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Existence of tachyons [closed]
I know that none of the experiments which have been conducted by physicists to conclusively prove the existence of tachyons have been successful.
This got me thinking. What if, we cannot find tachyons ...
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Coulomb gas correlators on the sphere
I am trying to understand Appendix B.2 of Nakayama's notes (https://arxiv.org/abs/hep-th/0402009), wherein he derives the correlation functions of the following action (Coulomb gas) on the sphere:
$$ ...
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Two-way tachyonic anti-telephone
Consider the two-way tachyonic antitelephone where the speed at which message is transmitted is $a$. A person $A$ sends a message to $B$ which is moving away with a speed of $v$ with respect to $A$. ...
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One-way Tachyonic anti-telephone
When you have length contraction in special relativity
$$L' = L/\gamma$$ the interpretation is that $L'$ is the length of an object with rest-length $L$ moving with respect to an observer at rest. ...
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Tachyonic instabilities [closed]
How to find tachyonic instabilities for some parameter ranges in the $f(R)$ gravity model? I have tried to find the parameter ranges for exponential $f(R)$ model, Starobinsky $f(R)$ model and ...
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$g$-function and D-brane tension
In https://arxiv.org/abs/hep-th/0009148 page 9 it is said that at the fixed points of the RG-flow of the open bosonic string , the $g$-function has stationary points which are the D-brane tensions. ...
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Can we compute tree-level amplitudes in string theory using the fundamental domain of $SL(2; \mathbb{C})$?
I am not a specialist in string theory. I understand the computation of tree-level string amplitudes (Veneziano or Virasoro-Shapiro), where three variables are fixed using the symmetry $SL(2;\mathbb{C}...
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Tachyon Mass as Frame-Dependent?
So, as I was browsing a bunch of the tachyon questions throughout the years in this forum, and an oddity of these hypothetical faster-than-light particles came to mind. Ordinary particles with mass ...
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Correlation function of tachyon vertex operators
In Polchinski's first volume on String Theory, it is claimed in exercise 2.3 (or analogously in eq.(6.2.17)) that
$$ \Bigl\langle \prod_{i=1}^N : e^{i k_i \cdot X_i(z_i,\bar{z}_i)} : \Bigr \rangle = i ...
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What is innermost unstable circular orbit (IUCO)?
In the paper Tachyon motion in a black hole gravitational field by V. M. Lipunov he writes:
(…) Circular orbits for tachyons begin at the distance of $ 3/2~r_g $, i.e., at the distance of the ...
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Is black hole event horizon a transcendent tachyon?
In static spherically symmetric spacetime with metric $$ds^2=e^{2\nu}c^2dt^2-e^{2\lambda} dr^2-r^2 (d\theta^2+\sin{\theta}~d\phi^2)\equiv \delta_1~c^2 d\tau^2 \tag{1}$$ the geodesic equation in ...
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