Questions tagged [string-field-theory]
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Level truncation in String Field Theory
In string field theory, to study tachyon condensation at level-2, the string field is truncated to $$\Psi=t c_{1}|0\rangle+ u c_{-1}|0\rangle+ v L_{-2}^{(m)} c_{1}|0\rangle,$$ where $t,u, v$ are ...
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Tachyon mode in Brane-Antibrane system (Type II)
Lets First start with coincident $D3$ brane- $D3$ Brane system. Superstring stretch between these two contain a Tachyon mode But GSO projection removes this. For open string, $D$ branes serve just as ...
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65 views
String topology in string theory
How do string topology, string field theory and topological strings interact? Does anybody see a global picture? By string topology I mean the TQFT based on the homology of the space of loops ...
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1answer
58 views
Classical field theory with fields on different base spaces
Keeping things at a "basic level", a field is a function from a base manifold (of dimension D) to some other space. Usually the base manifold is the spacetime but may be something different (a lattice,...
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1answer
102 views
Does string theory violate general covariance?
In a 2007 note on ArXiv, it said:
String theory unifies all interaction but provides a perturbative background dependent formulation which violates general covariance.
However, another 2012 paper ...
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41 views
Could every particle encode the distances to all other particles?
I was thinking about quantum gravity and pre-geometry and wondering this question:
"If space does not exist. How does a particle know how far away it is from another particle?"
i.e. there are no ...
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1answer
173 views
How can you show diffeomorphism invariance of closed string field theory?
String Field theory if it predicts General Relativity should have 26D space-time diffeomorphism invariance (presumably). How can one show that Closed String Field Theory has this symmetry?
(Besides ...
4
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1answer
509 views
How do strings (in string theory) get created or destroyed?
Something has been bothering me about string theory. From what I can tell, string theory is a first quantized theory of the position and momenta along a string, and that the fields of QFT are not ...
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100 views
Is it true the Michio Kaku has completed a unified field theory started by Einstein by making use of string theory? [duplicate]
This professor has a few documentaries available explaining science to the layman like myself and he showed an equation no longer then a sentence that he says unifies all the know forces and particles ...
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1answer
571 views
Is the String Field of String Field Theory the same (ontologically identical to) as the field of QFT?
Disclaimer: Although my maths is quite good and I have a background in computer science and software engineering, I am a philosopher specialising in information theory (and what is called the ...
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24 views
Do Aichelburg-Sexl spacetime give excitation to a string?
I read about an article stating the excitation of a charged string passing through a shockwave in the Aichelburg-Sexl spacetime, how does it excites the string?
3
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1answer
255 views
Witten's Open String Field Theory vs. Light Cone Quantization?
I am a quite confused on the differences between these two formulations of open string field theory, and am unable to reconcile how they are related. M. Kaku's 1972 paper formulates a string field ...
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93 views
Flux compactifications and the scalar potential
Does the scalar potential:
$$V=e^K(K^{I \bar{J}})D_IW D_{\bar{J}}\bar{W}-3|W|^2$$
where $K$ is the Kähler potential and $W$ the superpotential, $D=\partial_I+\partial_IK$ and $I$ runs over all the ...
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0answers
66 views
Where is a proof that string field theory is generally covariant?
Given a space-time coordinate of a string $X^\mu(\sigma)$ dependent on the position $\sigma$ around the string. And a string field functional $\Phi[X]$, is there a proof that the equations of motion (...
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0answers
111 views
What is the “single equation” in string theory that's an inch long? [duplicate]
Michio Kaku, famous theoretical physicist claims to be one of the founders of string field theory and to have contributed a equation that's "no bigger than your thumb" that ties general relativity and ...
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1answer
5k views
What is Kaku's equation about?
When Michio Kaku talks about science he often likes to refer to string theory and sometimes to his equation which looks like this (not sure if wrote right):
$$L = \Phi^\dagger[i\partial_{\tau}-H]\Phi +...
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0answers
124 views
Brane interactions?
In particle physics, in QFT's, interactions come from the interaction piece in the Lagrangian (action). In string theory, waiting for a complete formulation of SFT, we have to add "by hand" ...
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1answer
461 views
Review of String Field Theory
Could anybody suggest the comprehensive review of String Field Theory? Original papers are lengthy and it would take quite a long time to read them all.
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2answers
446 views
String Field Theory and AdS/CFT
I am a PhD student and I am choosing the topic to work on in the graduate school. I am interested in various non-perturbative aspects of String Theory. Does anybody know if there were any attempts to ...
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1answer
460 views
Has Sen quantized superstring fields?
Today I saw a paper by Ashoke Sen titled "BV Master Action for Heterotic and Type II String Field Theories".
Is it really the "quantization" of superstring fields for the first time?
What can be its ...
3
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1answer
95 views
What is meant by the following divergent formula?
I have encountered the following formula a couple of times (in different physics contexts which I do not have a good understanding of)
$$\int_{0}^\infty \frac{dt}{t}e^{-tx}=-\log x$$
Formally one ...
2
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1answer
151 views
Can the strings in string theory be thought of as troughs in a field?
I figure that string theory is a new breed of QFT which looks at fields in terms of a network of strings and also incorporates gravity into its module, however my question is that since elementary ...
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3answers
188 views
What is the general theory that describes the interactions between strings?
What is the general theory that describes the interactions between strings? I mean the basic object in the theory is (closed) string and they have interactions among them. The string theory, as I ...
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1answer
261 views
Why do people look for a field formalism for String Theory
String theory was originally formulated from a perturbative description (using quantum mechanics (QM) and replacing points by strings and evaluating path integral). Still, although QM has an upgrade ...
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0answers
163 views
Why is it difficult to construct the Ramond-Ramond sector in Berkovits' SFT?
I've been trying to get familiar with string field theory (SFT) and I've stumbled upon the statement that the Ramond-Ramond (RR) sector of Nathan's SFT has not been constructed yet. Why is that?
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2answers
329 views
A three string tree diagram evaluated in CFT is different from string field theory evaluation
Hi Guys generally when you evaluate the 3 open string tachyon tree level amplitude in CFT, you do a conformal transformation mapping the worldsheet to the upper half of the complex plane and the ...
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8answers
20k views
What are the strings in string theory made of?
This is a follow-up to an intriguing question last year about tension in string theory.
What are the strings in string theory composed of?
I am serious. Strings made of matter are complex objects ...
3
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1answer
166 views
How to deal with crossing duality and modular invariance in string field theory?
An answer I gave elsewhere.
Some cases to ponder over.
A closed string splits into two closed strings, which then merge again into a single closed string. The overall string worldsheet has the ...
3
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1answer
464 views
Why do strings split in string theory?
In string theory, we are told strings can split and merge if the string coupling is nonzero, even while the worldsheet action remains Nambu-Goto or Polyakov plus a topological term. However, a ...
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3answers
1k views
Is String Theory a Field Theory?
Is String Theory a Field or Quantum Mechanical Theory of the String rather than a Particle?
I should know this having studied this for a term, but we jumped into the deep end, without really ...
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1answer
310 views
Is there a background independent closed string field theory?
Analogous to the background independent open string field theory by Witten. If there isn't, what are the main stumbling blocks preventing its construction?
17
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1answer
720 views
Is string theory local?
By locality I mean something like the Atiyah-Segal axioms for Riemannian cobordisms (see e.g. http://ncatlab.org/nlab/show/FQFT). I.e. to any (spacelike) hypersurface in the target we associate a ...
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2answers
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What does second quantization mean in the context of string theory?
String field theory (in which string theory undergoes "second quantization") seems to reside in the backwaters of discussions of string theory. What does second quantization mean in the context of a ...
