Questions tagged [string-theory]
A class of theories that attempt to explain all existing particles (including force carriers) as vibrational modes of extended objects, such as the 1-dimensional fundamental string. PLEASE DO NOT USE THIS TAG for non-relativistic material strings, such as, e.g., a guitar string.
2,862 questions
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Why can we not constrain Calabi-Yau manifolds from observations like we do cosmological parameters?
Why can we not constrain from observations the parameters of a possible Calabi-Yau compactification in string theory the same way we constrain parameters in cosmology? I work in high-$z$ astrophysics, ...
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How to derive Polyakov's 2d quantum gravity functional in light cone gauge?
I am trying to derive the action Polyakov presents in his 1987 paper Quantum Gravity in two dimensions, in the following form,
$$W[f] = \frac{c}{24\pi}\int \mathrm{d}^2 z \, \frac{\partial_{\bar z} f}{...
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Can fundamental physical constants be explained via dimensions linked to π, e, and φ? [closed]
I'm developing a theoretical framework where fundamental mathematical constants π (3.14159...), e (2.71828...), and φ (1.61803...) are treated as compactified dimensions in an extended spacetime.
Core ...
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Riemann 2-manifold volume form: complex vs real
Question 1: is it always possible to write the metric in that form? Is it sufficient the local conformally-flat form to obtain the volume?
Question 2: Is the volume form in (4.1) well-defined? Going ...
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Can a universe with only one spatial dimension and one time dimension still produce complex physical behaviour? [closed]
Can a universe with only one spatial dimension and one time dimension still have meaningful physics? For example, can quantum fields in 1+1 dimensions produce effects similar to higher dimensions, or ...
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Worldsheet ADM Formalism & Hamiltonian Path Integral
Consider the following bosonic NS-NS sector of closed string worldsheet action, having the following spacetime fields - metric tensor $G_{\mu\nu}(x)$ Kalb-Ramond Field $B_{\mu\nu}(x)$ and scalar ...
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EOM of Nambu-Goto in second fundamental form
I am computing the EOM of the Nambu-Goto action $$S[X] = -T\int d^2 \sigma \sqrt{-\det{(\partial_a X^\mu \partial_b X_\mu)}}$$ and I want to write this in a specific form using the second fundamental ...
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D-branes, string field theory, and Chern-Simons
Reading the book$^{\dagger}$ Chern-Simons Theory, Matrix Models, and Topological Strings by Marcos Marino, I'm trying to understand the argument in 7.3.2: here are my main questions which can also be ...
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How to calculus the corresponding operators of bosonic beta-gamma ghost systems? [closed]
In Polchinski's book, it states that the corresponding operators of $|1\rangle, |-1\rangle$ are $\delta(\beta),\delta(\gamma)$, and suggests that it can be shown by path integral. I'm a little ...
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Structure constants of quantum cohomology of (partial and complete) flag varieties [closed]
I have an extremely efficient way to compute the structure constants of the quantum cohomology rings of partial flag varieties (which are modeled by quantum (parabolic) Schubert polynomials, the three-...
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Integrals in Euclidean plane with complexified coordinates?
Calculations are carried out in Euclidean plane with complexified coordinates $z,\bar{z}$ as we do in CFT. I need to derive the following:
$$\int{\frac{d^2 z_1}{(z-z_1)(\bar{z_1}-\bar{w})}}=\pi\ln{|z-...
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Why are strings in string theory considered as elementary?
I was reading "The classical theory of fields" by Landau & Lifshitz and, in the beginning of the third chapter of the 4th edition, they explain that the existence of a rigid body is ...
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How does string theory handle non-renormalizability of QED in $d>4$?
Quantum electrodynamics is non-renormalizable in more than four dimensions (see Peskin & Schroeder, chapter 10). This would seem to put it on similar footing as gravity for $d>4$ in the sense ...
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Why is the string worldsheet theory a CFT?
Why do we say that the (gauge-fixed) worldsheet theory in string theory is a conformal field theory (CFT)? Where exactly does this conformal invariance come from? Is it simply because, after gauge ...
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Why conformal gauge?
In the path integral of the bosonic string, we fix the gauge by setting the metric $ h $ to a reference metric $ \hat{h} $. A common choice is the conformal gauge:
\begin{equation}
h_{\alpha \beta} \...
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