Questions tagged [supergravity]

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

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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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Definition of $F_5$ in Type IIB Supergavity

Type IIB Supergravity has a 5-form, which is usually written the following way: \begin{equation} \hat{F}_5=F_5+\frac{1}{2}B_2\wedge F_3-\frac{1}{2}C_2\wedge H_3 \end{equation} Some references, write ...
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T-duality rules between D-branes and E-branes

I am trying to understand the time-like T-duality rules in Type II effective actions, and how they relate D-branes to E-branes. In the case of the metric and dilaton, the Buscher rules are unchanged ...
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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 anyone ...
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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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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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General expression for a Scalar Superfield with ${\cal N = 1}$ in $D = 10$

I need to write explicitly the most general form of a scalar superfield in 10 dimensions up to second order in grassman variables $\theta^\alpha$. I know that up to first order one can write \begin{...
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Gauge theory formalism

Source: Chapter 11 of Freedman and Van Proeyen’s supergravity textbook An infinitesimal symmetry transformation is determined by 1) a parameter, call it $\epsilon^A$, and 2) an operation, call ...
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General gauge algebra identity

In https://arxiv.org/abs/1011.1145 the following rather general gauge algebra identity (2.4) is used $$\delta_{gct}(\xi) B_\mu^{\>\>A} + \xi^\lambda R_{\mu\lambda}^{\quad\! A} -\sum_{\{C\}}\...
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What is the $R$-symmetry group for ${\cal N}=6$ supergravity in $D=4$ dimensions?

What is the $R$-symmetry group for ${\cal N}=6$ supergravity in $D=4$ dimensions?
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How Quintic 3-fold is a Calabi–Yau manifold and has non-vanishing Ricci scalar?

It’s well known that quintic 3-fold is a Calabi-Yau manifold in the complex projective space $\mathbb{CP}^{n+1}$ , see for instance: https://en.wikipedia.org/wiki/Quintic_threefold Now the main ...
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Gravity and complex numbers

In the lectures of Gary Gibbons on Supergravity held 2009@DAMTP http://www.damtp.cam.ac.uk/research/gr/members/gibbons/gwgPartIII_Supergravity.pdf it is remarkable that when he introduces spinors he ...
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Describing Calabi–Yau 3-fold

Background: In Calabi-Yau 3-fold, the Kähler metric is given in terms of the Kähler potential $\kappa$ : $ g_{i\bar{j}} = \partial_i \partial_{\bar{j}} \kappa$, where $i, \bar{j}$ = 1,2,3 $ ( the ...
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Holographic duals of (super)gravity sigma models

Consider a (super)gravity theory on asymptotically AdS spacetime $N$ with fixed conformal boundary $\partial N$ coupled to scalars $\phi_i$ taking values in a manifold $M$, possibly in addition to ...
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Toroidal compactifications of type IIB string Theory and $SO(5,5)/(SO(5)\times SO(5))$ invariant 6D sugra action

It is usually stated that the compactification of (the bosonic part of the) type IIB ($D=10$, ${\cal N}=(2,0)$) supergravity on $\mathbb{T}^4$ gives a six-dimensional ${\cal N}=(4,4)$ supergravity ...
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Gravitino Equation of motion in second-order formalism

In Freedman and Proeyen's text on supergravity they derive the equation of motion for the gravitino using the second order formalism. However, I'm not exactly clear as to how they use partial ...
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Determination of Torsion constraints in ${\cal N} = 1$, D = 10 Superspace

For the on-shell theory, containing the graviton $e_m^{\ \ \ a}$, gravitino $\psi_m^{\ \ \ \alpha}$, dilaton $\phi$, dilatino $\lambda$ and 3-form $H_{n m p}$, one has to demand that the SUSY algebra ...
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Supergravity and Gamma Matrices

On page 101 of Freedman and Van Proeyen's book on Supergravity they find the propagator of the gravitino, however I'm not sure how to work through the steps in (5.30), and hints or answers would be ...
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What is a global limit in gauged supergravity?

Does anyone know what a global limit (rigid limit), where the gauge coupling constant is zero, in gauged supergravity is?
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IIB Supergravity from worldsheet (super)conformal invariance of Green-Schwarz string

After reading this question How are low energy effective actions derived in string theory? I began to wonder what is the coupling of the string to the other sugra fields. In almost all textbooks ...
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Why are photons particles and waves, instead of particles that simply move in a wave pattern?

I understand the double slit experiment, but even with the results, why are photons determined to be particles and waves at the same time, instead of particles that move in a wave pattern? In bodies ...

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