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.

learn more… | top users | synonyms (7)

1
vote
0answers
95 views

Are strings in string theory actually little black holes? [on hold]

I sometimes read that strings in string theory are actually little black holes, or can be interpreted that way. Is this true? How is that consistent with that the particle that a string represents ...
1
vote
1answer
49 views

What is the difference between worldsheet supersymmetry and spacetime supersymmetry?

What is the difference between worldsheet supersymmetry and spacetime supersymmetry? For worldline formulation of fermions quantum mechanics, there is a supersymmetry. But the corresponding spacetime ...
3
votes
0answers
23 views

Multi-Cut Matrix Models

I have a question pertaining specifically to a one-matrix model with a multi-cut solution. The standard procedure is to take a polynomial superpotential $W(x)$. In the classical limit (analogous to $...
-4
votes
0answers
20 views

Are electrons packets of energies made up of strings? [closed]

I always wondered that if electron was a packet of energy it would hold true for most of the experiments and we won't need to deal with wave particle duality anymore,but then matter came in.what if ...
4
votes
2answers
121 views

What does string theory predict for the singularity inside a black hole?

The usual explanation for what's going on inside a black hole goes something like "General Relativity predicts a singularity with infinite curvature, but when matters gets so tightly compressed we ...
1
vote
0answers
32 views

OPE coefficents and commutation relations, and OPE with stress tensor

Basic question about conformal field theory: In a conformal field theory in $d\geq 3$ dimensions, what is the relation between commutation relations and OPE coefficients? In particular, because ...
0
votes
0answers
22 views

T-duality between $E_8 \times E_8$ and $\text{Spin(}32)/\mathbb{Z}_2$ heterotic strings at the $\sigma$-model level

I would like to understand how T-duality between the heterotic $E_8 \times E_8$ (HE) and heterotic $\textrm{Spin}(32)/\mathbb{Z}_2$ (HO) theories works, at the level of the worldsheet $\sigma$-model. ...
-1
votes
1answer
34 views

Do Quark confinement prevents proving strings? [closed]

In baryons like protons,neutrons;isolated quark doesn't exist due to quark confinement. We will need an infinite energy to pull quarks apart.Even if we try to pull them apart there will be pair ...
1
vote
1answer
51 views

How to calculate the free energy in curved space?

To study the Hagedorn temperature of string near a black hole, we need to calculate the free energy in curved space. This is can be done calculating a torus path integral, but I want to know if an ...
-1
votes
1answer
46 views

How do comparatively larger particles arise from vibrations of infinitely smaller strings?

In String Theory, how can a string as infinitesimally small as the Planck length, manifest itself as a much larger and massive particle?
1
vote
1answer
36 views

What is the spin of the Kalb-Ramond field?

In bosonic string theory the massless states of the closed string are given by a rank 2 tensor, which is divided into its three irreducible spherical tensors: symmetric traceless, antisymmetric and ...
0
votes
1answer
42 views

Do Calabi -Yau shapes also influence a strings particle identity?

Since strings reside on the surface of a d-brane, and it' a three dimensional hyperspace, are their manifestations as certain particles also influenced by Calabi Yau Spaces? Could the way strings ...
3
votes
2answers
63 views

Question about notation used in writing the moduli space in string theory

In physics papers, particularly those by Aspinwall, or textbooks, I encounter things like $$\mathcal{M} \simeq O(\Gamma_{4,20})\setminus O(4,20)/((O(4)\times O(20))$$ For instance, this is from ...
5
votes
2answers
105 views

String quantization and Malament's theorem

Malament's theorem posits that, given a few assumptions on relativistic QM, it is impossible to have localized particles. For $E_\Delta$ the proposition that a particle is certain to be found within a ...
-1
votes
3answers
96 views

In String Theory, can some particles contains multiple strings? [closed]

According to String Theory, can a particle consist of more than one string? I can visualize elementary particles, like leptons, being composed of a single string. But what about composite particles, ...
1
vote
1answer
86 views

What particles are closed strings?

In String Theory, I understand that gravitons are particles that are closed strings. Are there other particles that are manifested from closed strings?
2
votes
0answers
47 views

Reference for orbifolds in string- and M-theory

A number of orbifold constructions have been studied heavily in string- and M-theory over the years, establishing various dualities between different theories. Can someone point me to a slightly more ...
3
votes
1answer
51 views

Problem obtaining string equations from Polyakov action [closed]

I am trying to obtain the string equations of motion from the Polyakov action in the conformal gauge, i.e.: $$ S=T\int{d\tau d\sigma (\dot{x}^2-x^{'2})}\equiv\int{d\tau d\sigma \mathcal{L}} $$ where ...
3
votes
1answer
47 views

How many orientifold planes does one need?

According to the book ''String Theory in a Nutshell'' by Elias Kiritsis (page 204, linked here), the tension of an $Op$-plane is $$T_{Op} = -2^{p-4}T_{Dp}$$ With this picture, one gets -- for type ...
4
votes
0answers
55 views

For intersecting branes, are we allowed to compactify on a torus such that one of the branes becomes dense in it? What is the result?

The story of how to get chiral fermions in the low-energy effective theory of a string theory with intersecting branes goes something like this: At the point of intersection of two branes, a direct ...
1
vote
1answer
36 views

p-cycles and Fluxes

I would like to ask why the existence of a non-trivial p-cycle leads to a non-trivial flux. I would say that e.g. for a five-form $F_{(5)}$ field strength , the flux is: $$\int\limits_{\mathcal{C}^{5}}...
2
votes
1answer
29 views

Multi-center Taub-NUT geometry and homologically nontrivial cycles

In the string theory book by Ibanez and Uranga (click here for the Google books excerpt), the four-dimensional multi-center Taub-NUT metric is written as $$ds^2 = \frac{V(\textbf{x})}{4}d\textbf{x}^2 ...
1
vote
0answers
15 views

Query about Ramond-Ramond fluxes associated with a Dp-brane

A paragraph in the string theory book by Ibanez and Uranga (String Theory and Particle Physics by Luis Ibáñez and Angel Uranga) has confused me. According to the book (for a screenshot of the ...
2
votes
1answer
36 views

Exchanging a local operator with a path integral

I am reading a paper by J. Polchinski, called "What is string theory", hep-th/9411028. In eq. 1.1.9, and the line before it, the author seems to have used: $$\langle \partial_z \partial_{\bar{z}} X(z,...
3
votes
0answers
55 views

Higgs mechanism in quantum GLSM

My question is regarding the following Gauged Linear Sigma Model (GLSM) in two dimensions. $$\tag{1} S=\int d^2x\Big(-D_{\mu}\overline{\phi} D^{\mu}\phi +\frac{D^2}{2e'^2} +D(|\phi|^2-r)\Big).$$ ...
5
votes
2answers
57 views

Why cannot a fundamental string couple to the R-R gauge field $C_{\mu\nu}$?

People usually say that D-branes can carry R-R charges, or can couple to R-R sector gauge fields. But why a fundamental string cannot couple to a 2-form R-R sector gauge field? What's the essential ...
4
votes
1answer
77 views

What, exactly, is a “delta function p-form” as used in the theory of branes?

In string theory, when dealing with branes, the following happens: We rewrite a worldvolume action $S = \int_{\Sigma_{p+1}} \omega^{(p+1)}$ of a $D_p$-brane as an integral over the whole $\mathbb{R}^{...
1
vote
0answers
95 views

Question on $E_8$ and twistor space [closed]

The Kahler $4$ form constructed from two-forms $\{\alpha, \beta\} \in H^2(M,\mathbb Z)$, and $M$ a $4$-manifold, is induced by $\alpha\wedge\beta$ with the map $H^2(M, \mathbb Z)\otimes H^2(M, \mathbb ...
0
votes
0answers
34 views

Confusion regarding Vacuum fluctuations, Strings & The Casimir Effect

From Wikipedia: Casimir Effect The typical example is of the two uncharged conductive plates in a vacuum, placed a few nanometers apart. In a classical description, the lack of an external field ...
1
vote
1answer
36 views

Enhanced D-Brane Gauge Symmetry and the string decoupling limit

Consider a system of $N_C$ $Dp$-branes (in Type IIA or Type IIB string theory, depending on whether $p$ is even or odd). In the Les Houches lectures on supersymmetric gauge theories by Berman and ...
5
votes
1answer
121 views

Gravitational wave and string theory

I'm new to physics and have been reading about fundamental and textbook physics text, which is the Young & Freedman University Physics (good book). I'm little skeptical towards string theory as ...
6
votes
2answers
246 views

From Quantum Mechanics to Quantum field theory to String theory?

Today during a very "unique" study session, I might have internalized why Quantum mechanics was not enough, and Quantum field theory makes sense. It seems the reasons are that When a potential is ...
1
vote
0answers
27 views

What is the origin of the five-form field in bubbling Ads geometries?

I have been reading the paper: Bubbling Ads space and the 1/2 BPS geometries[hep-th/0409174]. In the paper they look at 1/2 BPS states in the field theory which are dual to D3 branes IIB supegravity. ...
1
vote
1answer
44 views

What relative effects be for object with near light speed velocity in compactified dimensions?

What relative effects be for an object with near light speed velocity in compactified dimensions? Does gravity increase the same as for an object with near light speed velocity in usual spacial ...
3
votes
0answers
42 views

Can random walks be applied to String Theory in curved space?

If we study the high temperature limit (near Hagedorn) of a string gas, most of the energy is concentrated in a single long string. If we model the string by a fixed number of rigid links of length ls ...
0
votes
1answer
61 views

Question about a formula in the book by Green, Schwarz, Witten

In chapter 7 of superstring theory, it is written $$ g\langle0;k_1|\zeta\cdot\alpha_1V_0(k_2)\zeta_3\cdot\alpha_{-1}|0;k_3\rangle=g\langle0;k_1|\zeta\cdot\alpha_1e^{k_2\cdot\alpha_{-1}} e^{-k_2\cdot\...
0
votes
0answers
35 views

Mathematician wanting to learn cutting edge physics [duplicate]

I have interest in and wanted to learn modern physics including string theory,relativity,etc. But I'm currently a mathematics major and not a physics major, thus I'm train as a mathematician and not ...
1
vote
0answers
44 views

Why RR cohomology is important in string theory?

I want to know the RR cohomology in string theory or topological field theory in detail. (RR stands for Ramond Ramond). In following papers they compute the nilpotency of differential operator for RR ...
4
votes
1answer
47 views

What kind of fields can couple naturally to a $p$-form gauge fields in a Lagrangian?

Ordinary $U(1)$ gauge fields can naturally couple to classical fields such as spin-$1/2$ fields via the Dirac Lagrangian, or to complex spin-$0$ fields via the obvious covariant derivative coupling, ...
1
vote
0answers
30 views

Applying AdS-CFT to traversable wormholes? [closed]

ER=EPR recently brought up the connection between non-traversable wormholes and entanglements. What about traversable wormholes? Can we apply AdS/CFT to traversable wormholes?
1
vote
1answer
75 views

Is most of what everything is made from in another dimension?

If there are eleven dimensions as M-Theory asserts would that mean that the majority of what we are made from exists in the seven other dimensions?
3
votes
1answer
63 views

From states in string theory to differential forms

This question is probably really easy and isn't usually discussed in textbooks. So suppose when we construct states in string theory we obtain something like $\left|- \right\rangle \otimes \left|+ \...
0
votes
1answer
110 views

How can Big Bang happen without time?

I had recently watched a video and he says big bang could have happen by the slow collision rather than a fast collision. But I know that there was no time before the big bang and fast and slow are ...
2
votes
0answers
35 views

Which supersymmetry principles make the axio-dilaton field in F-theory holomorphic?

I am following the lecture notes on F-theory by T. Weigand . On page 7 he states that when considering F-theory as the strong coupling limit of type IIB orientifolds with D-branes, the axio-dilaton ...
7
votes
3answers
96 views

Are dimensionless physical constants predicted to be rational, irrational, or transcendental numbers?

Are dimensionless physical constants predicted to be rational, irrational, or transcendental numbers? Directly measured ones are obviously unknown, but according to Wikipedia many dimensionless ...
0
votes
1answer
25 views

What artefacts of the ant on a wire analogy for string theory's curled extra dimensions are due to the analogy breaking down?

I'm trying to understand the ant on a telephone-wire analogy that's used to explain why we might not see the extra dimensions from string theory. I'm quite comfortable with Newtonian mechanics in 3D, ...
1
vote
1answer
45 views

Why supersymmetry requires either left or right movers to vanish for a $S^1$ compactification

In the chapter on Black holes in string theory (Section 11.4, page 584 near equation 11.94) in the book by Becker, Becker and Schwarz, they write [...] let us consider a single string wound $Q_1 ...
1
vote
0answers
35 views

Ramond-Ramond potential and field strenght

I have a doubt about R-R potential in Superstring theory. The known facts are (according many books, for example "Basic Concepts in String Theory" by R. Blumenhagen, D. Lüst and S. Theisen): in the ...
1
vote
1answer
37 views

Type II Superstring and Open String

I would like to trow away some confusion I'm accumulating. Usually when superstrings are introducted (see for example Wikipedia) one says: Type I is a theory of open and closed strings, while Type ...
1
vote
1answer
51 views

Boson in Superstring

I'm confused about a point. Superstring sigma model is $$ S=-\frac{T}{2}\int\mathrm{d}^2z \left[\eta^{ab}\partial_aX^\mu\partial_b X_\mu -i\bar\psi^\mu\rho^a\partial_a\psi_\mu \right], $$ of course, ...