For questions about string theory

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1answer
39 views

How many bit strings of length 7 exist if the string remains unchanged if it is reversed?

How many bit strings of length 7 exist if the string remains unchanged if it is reversed ? 1 1 1 1 1 1 1 and 1 0 0 1 0 0 1 are an example that is unchanged if reversed. 0 0 0 0 0 0 0 and 0 1 1 0 1 1 ...
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0answers
50 views

Polchinski 12.3.22 - superspace green's function

Forming the supersymmetric string using superfields and superspace, Polchinski claims that the function $$ G \sim \ln{\left|z_{1} - z_{2} - \theta_{1}\theta_{2}\right|^{2}} $$ satisfies the equation ...
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kac moody algebra and pde

I study PDE via Lie groups method, I also very much into Lie theory, including the infinite dimensional version. Recently I come across some infinite dimensional Lie algebra so-called Kac Moody ...
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1answer
70 views

String probability (with conditional prob and combinations)

I'm having trouble with the questions below, all relating to string probability. I'll write the problem and then provide my work for my (incorrect) answer. Please help me figure out what I did wrong. ...
3
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1answer
81 views

Why are there cubics in a Calabi-Yau manifold?

I heard from a recent talk that the "number of $n$-degree curves" in a Calabi-Yau manifold is an invariant of the space. But what does that mean? (Specifically I would like to ask the following.) ...
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2answers
414 views

Complex and Kähler-manifolds

I was woundering if anyone knows any good references about Kähler and complex manifolds? I'm studying supergravity theories and for the simpelest N=1 supergravity we'll get these. Now in the ...
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0answers
35 views

Physical interpretation of categorical structures related to Dirichlet Branes

In Dirichlet Branes and Mirror Symmetry by Aspinwall et al, section 5.9 discusses various questions that remain open. In particular they say: "There are many constructions from homological ...
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77 views

Status of a question from Freeman Dyson's 1972 article

In a famous article, Freeman Dyson mentions an interesting relationship between the $\tau$ functions of number theory and the dimensions of finite-dimensional simple Lie algebras (section 2). He ...
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99 views

Solving numerically the equation of motion of D7 brane perturbation

I want to solve this equation $$ \partial_{\rho}^{2}\phi+\frac{3}{\rho}\partial_{\rho}\phi+\left(\frac{M^{2}}{(1+\rho^{2})^{2}}-\frac{l(l+2)}{\rho^{2}}\right)\phi=0 $$ numerically. I know that ...
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1answer
40 views

Strange factor multiplying the fermionic part in the NS mass-squared operator?

In the Neveu-Schwarz sector, the worldsheet fermions can be expanded as $$ \psi^I(\tau,\sigma) \sim \sum\limits_{r\in Z+1/2}b_r^Ie^{-ir(\tau-\sigma)} $$ and the total mass squared operator can then ...
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0answers
74 views

rigorous treatment of infinitesimal reparametrizations

my first post :) I am asking this directed to mathematicians or mathematical physicists since I don't like the usual physics approach. Reading some string theory books I always find that the ...
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1answer
209 views

What is a good gentle introduction to the Virasoro algebra and its application in theoretical physics?

I am looking for an as gentle and pedagogical as possible introduction that explains the Virasoro algebra and its applications in theoretical physics; finally I am interested in its application in ...
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2answers
196 views

What's the difference between an orbifold with a conical singularity and a conifold?

In Becker, Becker, Schwarz's book 'String Theory and M-Theory: A Modern Introduction', page 360 they explain how an orbifold of $\mathbb{C}/\mathbb{Z}_{2}$ (which is equivalent to ...
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0answers
477 views

What Areas Should a Potential String Theorist Study at Graduate Level? [closed]

Next October I start a year long course in Cambridge, intended as preparation for a PhD. I chose mainly pure disciplines as an undergrad (particularly topology and analysis) but I'd really like to ...
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1answer
137 views

Find an upper bound for lowest eigenvalue using calculus of variations.

So I'm doing a little calculus of variations on an eigenvalue problem. The goal of this is to find an upper bound for the $\omega_0$ as follows: $\omega_0^2 \leq ...
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1answer
1k views

Algebraic Geometry in String Theory?

I'm currently studying String Theory and hope to do research in this area. I have now reached a point where even with a background in Mathematics instead of Physics, I have no clue what's going on ...
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4answers
6k views

String Theory: What to do?

This is going to be a relatively broad/open-ended question, so I apologize before hand if it is the wrong place to ask this. Anyways, I'm currently a 3rd year undergraduate starting to more seriously ...