# Questions tagged [supergravity]

Supergravity is a classical supersymmetric unification theory. It appears in low-energy classical limits of string-theory.

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### Dimensional reduction of supermultiplets

Consider the (10d) IIA supergravity multiplet: (in terms of $SO(8)$ representations) a graviton $\boldsymbol{44}$, a 1-form $\boldsymbol{8}_V$, a 2-form $\boldsymbol{28}$, a 3-form $\boldsymbol{56}_V$,...
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### What is the problem with classical fermionic field?

Consider classical fermionic field. We have it's action, equations of motion and so we can get it's solutions, right? For example, we can consider gravitational solutions with fermions (in particular, ... 1 vote
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### Supergravity in our universe

In "On supergravity theories, after ~40 years" (Jean-Pierre Derendinger) presented on DISCRETE 2014" it is said (p.16) that a positive cosmological constant is not compatible with ...
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### Kaluza-Klein reducing the Chern-Simons term in 11D supergravity

In 11D supergravity we have the Chern-Simons term of the 3-form field $C$ \begin{equation} \int C \land d C \land d C \end{equation} I want to consider this on a spacetime $\mathbb{R}^{1,6}\times S$ ...
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### Charge conjugation of symplectic Majorana spinors in 4+1 dimensions

In the book "Supergravity" written by Freedman & van Proeyen, a symplectic Majorana spinor is defined in eq. (3.86) $$\chi^i = \varepsilon^{ij} (\chi^j)^C, \tag{3.86}$$ where the upper ...
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### Is the 11th dimension in M-theory a line or a circle?

I'm familiarizing myself with $M$-theory and I think I get the big picture now, but I've read different accounts on this. According to some expositions by people that I think know what they are ...
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### Is the black brane picture valid only at small string coupling?

As far as I am aware there are two pictures of branes: for $g_SN\gg1$: branes as solitonic solutions to the field equations of supergravity (i.e. black branes) for $g_SN\ll1$: branes as fundamental ...
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### How to Wick rotate differential forms?

The bosonic sector of the Cremmer-Julia-Sherk (CJS) 11D supergravity action is $$eR-\frac12 F\wedge *F-\frac16 A\wedge F\wedge F,$$ where $F=dA$ is a 4-form field strength. How would one perform a ...
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### MAGOO 2-Point Correlation function derivation

I am studying the famous MAGOO review and I am trying to understand section 3.3 where we calculate the correlation functions from the AdS side. In subsection 3.3.1 the authors go through the 2-point ...
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### Deriving an action from a metric

I try to find out how in this paper https://arxiv.org/abs/hep-ph/9905221 the authors derived an effective action from the metric. The paper I study is related to string theory and modified gravity ...
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### Symplectic Majorana spinors in 5D

According to the book "Supergravity" written by Freedman & van Proeyen in 5D for the existence of Majorana spinors it is necessary to introduce so called sympletic ones which requires ...
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### Can I just add a cosmological constant to an on-shell supergravity action?

Suppose one has some supergravity Lagrangian $\mathcal{L}_\text{sugra}$ in flat (Minkowski) space. Moreover, assume that this Lagrangian is on-shell, in the sense that the auxiliary fields have been ...
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### Supergravity 3-form $C$ fields from 2d string worldsheets

In supergravity, there are 3-form fields known as C fields. However, according to string theory, the fundamental degrees of freedoms are from string worldsheets (so at most they are fundamentally 2d). ...
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### Is three dimensional supergravity dynamical?

So it is well known that standard $D = 3$ Einstein gravity is non-dynamical in the sense that the graviton has no on-shell degrees of freedom (d.o.f $= D(D-3)/2$ and the theory is topological). ...
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### How do branes come into existence according to string theory? [closed]

How do branes come into existence according to string theory? Also what are branes made out of?
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### What is NS5 brane?

NS5 brane can be considered as 1/2 BPS solution in supergravity (with other solutions to compare): This branes of Type IIA/B supergravity are expected to extend to solutions of the full Type IIA/B ...
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### SUGRA & consistent field theories

Why must a consistent theory with a rarita schwinger field (i.e. massless gravitino in the spectrum) be supersymmetric? I was reviewing the GSO projection, Spin Structure, etc. & wasn’t able to ...
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### Jacobi Identity in de Sitter Superalgebra

In the book "Supergravity" (by D. Freedman and A. Van Proeyen) they talk about why $\mathcal{N}=1$ de-sitter superalgebra is impossible to construct (Section 12.6.1). Basically de-Sitter algebra is a ...
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### Why the maximum number of supercharges in supergravity must be $Q=32$?

For a supergravity theory not to have particles with spin greater than 2, all books state that $Q\leq 32$, where $Q$ is the number of fermionic supercharges and for a given dimension $D$ it's related ...
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### Recommendation for supegravity in 10D

Is there a good book/review, concerning supergravity in 10 dimensions, which ideally also discusses some solutions like the $AdS_5\times S^5$ solution, or the Janus throat? The main resource I know is ...
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### Why does invariance commute with partial derivative?

This question applies more generally to actions, but I am going to ask it for a specific example. I am getting confused when considering the invariance of the superstring action under Weyl ...
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### String quantum cosmology

In canonical quantum gravity we have Wheeler–DeWitt equation and we can chose homogeneous and isotropic ansatz (it kills many problems) to describe quantum universe. In string theory, as I understand,... 92 views

### Tadpole cancellation condition for $C_4$ in Type IIB Supergravity theory

In the following I use Polchinski's notation. Type IIB Supergravity action (with non-vanishing fluxes & $\rm{D3}$-branes) contains \begin{align} S_{\mathrm{IIB}} &= S_{\mathrm{NS}} + S_{\...
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