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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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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Would zero-energy tachyon fluid exert pressure?
Due to relativistic energy momentum relation a tachyon of mass $m_{0}$ and of zero energy poses momentum $p=m_{0}c$. Because flow of momentum is pressure one can imagine that a spacetime filled with ...
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Why do we assume that we can change the past by sending signals backwards in time? [closed]
This might be a stupid question, but hang in with me-
From what I've seen, the biggest argument against superluminal signaling is that you would be able to send a message backwards in time that could ...
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Does the tachyonic antitelephone actually show a time-travel paradox? [duplicate]
The tachyonic antitelephone paradox is, roughly, this:
Alice is in a space station and watches Bob go past at relativistic speed in a spaceship. Some time later she sends him a message at ...
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Does Einstein’s original paper on relativity predict antiparticles and tachyons?
In Einstein’s original paper on relativity (pages refer to this copy) page 149 he gets an initial form of the now known as Lorentz transformation
$$\mathbf{x’}=\phi(v) \Lambda \mathbf{x} \tag{1}$$
(I ...
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Klein-Gordon equation with imaginary mass
I was wondering if someone could provide me the name of the following equation
$$\square \varphi - \tilde{m}^2 \varphi = 0,$$
where $\square := \partial_t^2 - \nabla^2$. I am specifically seeking ...
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