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, ...
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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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Anti-de Sitter superalgebra from preserved symmetry

Following Freedman & Van Proeyen's "Supergravity", the $\mathcal{N}=1,\, D=4$ AdS supergravity action is $$ \dfrac{1}{2\kappa^2}\int d^4x \; e \left[R(\omega) - \bar{\psi}_\mu \gamma^{\...
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Spin-2 operators from metric fluctuations in the AdS/CFT

This is a computational question. I am pretty sure that there is a simple explanation, and something obvious that I am missing but I cannot figure it out. I want to add that this is not meant to be a &...
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Can local supersymmetry be characterized entirely in terms of observables?

Global symmetries can be defined through their effect on observables. In contrast, quantum theories are often constructed with the help of symmetries that leave observables invariant, like the ...
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Confusion about Generating Functionals in AdS/CFT

I have a question regarding an equation in the book "Gauge/Gravity Duality" by Martin Ammon and Johanna Erdmenger which however can also be found in other AdS/CFT books or lecture notes. The ...
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Dimensional Reduction and Supersymmetry

I am working my way through "Basic Concepts of String Theory", by Blumenhagen, Lüst and Theisen. Currently I am working on the compactifications of string theories on Calabi-Yau manifolds. ...
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The volume of infinitly large extra dimension

What I understand is that, according to the string theory our universe is a membrane parallel to several other membranes or (universes). These parallel universes are separated by the bulk or extra ...
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Constraints on non-compactified extra dimensions

I'm reading this paper An introduction to extra dimensions and string phenomenology Which according to it, in string theory the 4-dimensional Plank scale is related to the Planck scale of ...
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Solving the hierarchy problem by large extra dimensions

I'm asking about the model of Arkani-Hamed-Dimopoulos-Dvali ( ADD ) to solve the hierarchy problem. https://arxiv.org/abs/hep-ph/9803315 According to this model, the 4- dimensional Planck scale $M_{pl}...
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The Hubble parameter of Randall-Sundrum model

It’s mentioned in this paper On the cosmological constant problem and brane-world geometry that the Hubble parameter of the Randall-Sundram model is given by: $$ H^2 = \frac{8\pi}{3m_{pl}^2} \rho + \...
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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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Modification of Riemann tensor by twisting the spin connection

Suppose one has a funfbein $e^a_{\mu}$ with associated spin connection $\omega^\mu_{\,ab}$. Writing this in terms of differential forms, $$e_a:=e_a^{\mu}\mathrm{d}x^{\mu},\ \ \ \omega_{ab}:=\omega^\...
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Is Supergravity just Super String Theory without open strings?

I'm trying to understand the elements of the AdS-CFT correspondence. The definition I have in mind is a correspondence between: (A) a Super String Theory of $D_p$-branes and closed strings in a $10$d ...
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What is a protected states in Supersymmetry, Superstring theory context

I know that they are the states that have protected scaling dimension when couplings are changed. But there are some states that are protected only in free orbifold theory, this is something I don't ...
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What is "string universality"?

I encountered the notion of "string universality" in the TASI lectures on Supergravity (April 2011). What does this actually mean? Does it mean that every consistent (in particular ...
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Is there a Lagrangian for Super-Gravity?

Einsteins field equations can be derived from the Einstein-Hilbert action which only involves the scalar curvature $R$ of the spacetime manifold. This is simply $$S = \int_M R.$$ The volume form or ...
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Which non-homogeneous scalar manifolds are possible in supergravity?

The scalar fields in various supergravity theories are restricted (by supersymmetry) to span the target (scalar) manifolds of a certain class (e.g. Hodge-Kahler, quaternion-Kahler etc.), depending on ...
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Gauging $R$-Symmetry

I know that if one gauges the supersymmetry group, you get supergravity. You can then further gauge the $R$-symmetry and these are the so-called gauged supergravities. But I don't think I've seen ...
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Precise zero energy bound for supersymmetry

Usually we can shift the energy $E$ by any amount $\delta$ to redefine the lowest energy as $$ E + \delta. $$ However, in supersymmetry, there is a precise $E=0$ must be true, so that the supercharge $...
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STU supergravity

Tghere are a lot of different papers about STU supergravity, for example see this. As I understand, STU supergravity is N = 2 supergravity coupled to three vector multiplets. Could someone explain, ...
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Dimensional reduction with supermanifolds and gravity

When having compact dimensions (I guess it is not true with supermanifolds), the gravitacional constant gets diluted in extra dimensional space: $$G_N(4d)=G_N(Dd)/V(X)$$ However, I presume that the ...
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Why is 11 Dimensional SUGRA not a consistent quantum theory?

I am studying the $S$ duality between 11D supergravity and type IIA superstring theory from Adel Bilal’s paper. The author says: Of course, eleven dimensional supergravity is not expected to yield a ...
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Kaluza-Klein supermultiplet of 11D supergravity

I am studying Adel Belali's review paper "M(atrix) theory: a pedagogical introduction" for my undergraduate thesis. In the third lecture, part one, we dimensionally reduce 11D supergravity ...
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Relationship between scaling dimension and mass in AdS/CFT

I've been reading Horatiu Nastase's notes on AdS/CFT, but I was confused about a certain relationship he claimed. If we compactify supergravity on $AdS_5\times S^5$, we may expand the fields in Kaluza-...
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How does one get supergravity from string theory? [duplicate]

I know one can get the Fermi theory of weak interactions as a low energy effective theory of the electroweak interaction by writing down Feynman amplitudes for weak decay processes, noting that $\...
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What does preserve a fraction of supersymmetry mean for black holes?

It is often mentioned in the literature that BPS black holes preserving some fraction of supersymmetry, eg $1/8$, $1/4$ and $1/2$. In the paper: BPS States with Extra Supersymmetry, by Jerome P. ...
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Why does the perturbative ($\mathcal{N}$=8, d=4) supergravity and type IIB closed string compactified on $T^{6}$ spectrums coincide?

The observation is that the perturbative spectrum of $\mathcal{N}$=8 supergravity in four dimensions is exactly the same as the type IIB closed superstring spectrum after dimensional reduction on $T^{...
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What is the form of local supersymmetry transformations in superspace?

So the most general local superspace transformation generator I can write is: $$\hat{L} = A^\mu(x,\theta)\frac{\partial}{\partial x^\mu} + B^\alpha(x,\theta)\frac{\partial}{\partial \theta^\alpha}$$ ...
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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,...
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4 votes
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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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String Landscape, De Sitter vacua and Broken Supersymmetry

If we assume that the swampland conjectures, etc. regarding de sitter vacuas existence in the string / F-theory landscape turn out to be incorrect (and therefore we can assume the problem is well-...

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