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The D’Auria-Fré formalism (D’Auria-Fré-Regge 80, D’Auria-Fré 80, Castellani-D’Auria-Fré 91) is a natural “superspace” formulation of supergravity in general dimensions, including type II supergravity and heterotic supergravity in dimension 10 as well as notably 11-dimensional supergravity.
This proceeds in generalization of how Einstein gravity in first order formulation of gravity is equivalently the Cartan geometry for the inclusion of the Lorentz group inside the Poincare group: a field configuration of the field of gravity is equivalently a Cartan connection for this subgroup inclusion.
Accordingly, low dimensional supergravity without extended supersymmetry is equivalently the super-Cartan geometry of the inclusion of the spin group into the super Poincaré group.
What D’Auria-Fré implicitly observe (not in this homotopy theoretic language though, that was developed in Sati-Schreiber-Stasheff 08, Fiorenza-Schreiber-Stasheff 10, Fiorenza-Sati-Schreiber 13) is that for higher supergravity with extended supersymmetry such as 11-dimensional supergravity with its M-theory super Lie algebra symmetry, the description of the fields is in the higher differential geometry version of Cartan geometry, namely higher Cartan geometry, where the super Poincare Lie algebra is replaced by one of its exceptional super Lie n-algebra extensions (those that also control the brane scan), such as notably the supergravity Lie 3-algebra and the supergravity Lie 6-algebra. This is the refinement of super-Cartan geometry to higher Cartan geometry.
This higher super Cartan geometry-description of supergravity is what D’Auria-Fré called the geometric approach to supergravity or geometric supergravity (e.g. D’Auria 20).
For more background on principal ∞-connections see also at ∞-Chern-Weil theory introduction.
Around 1981 D’Auria and Fré noticed, in GeSuGra, that the intricacies of various supergravity classical field theories have a strikingly powerful reformulation in terms of super semifree differential graded-commutative algebras.
They defined various such super dg-algebras and showed (paraphrasing somewhat) that
the field content, field strengths, covariant derivatives and Bianchi identities are all neatly encoded in terms of dg-algebra homomorphism ;
the action functionals of supergravity theories on such may be constructed as images under of certain elements in subject to natural conditions.
Their algorithm was considerably more powerful than earlier more pedestrian methods for construction such action functionals. The textbook CastellaniDAuriaFre on supergravity and string theory from the perspective of this formalism gives a comprehensive description of this approach.
We observe here that the D’Auria-Fre-formalism is ∞-Chern-Simons theory for ∞-Lie algebra-valued forms with values in super ∞-Lie algebras such as the supergravity Lie 3-algebra and the supergravity Lie 6-algebra.
The pivotal concept that allows to pass between this interpretation and the original formulation is the concept of ∞-Lie algebroid with its various incarnations:
(Incarnations of -Lie algebroids)
A (super) ∞-Lie algebroid
is an infinitesimal (super)∞-Lie groupoid
that may be modeled as a simplicial (super) infinitesimal space
whose function algebra is a cosimplicial (super) algebra
that under the monoidal Dold-Kan correspondence maps to a (super) semifree differential graded-commutative algebra: the Chevalley-Eilenberg algebra of the (super) ∞-Lie algebroid.
Notably the semifree dga upon which D’Auria-Fré base their description is the Chevalley-Eilenberg algebra of the supergravity Lie 3-algebra, which is an ∞-Lie algebra that is a higher central extension
of a super Poincare Lie algebra in the way the String Lie 2-algebra is a higher central extension of the special orthogonal Lie algebra .
A super connection on an ∞-bundle with values in on a supermanifold is locally given by ∞-Lie algebroid valued differential forms consisting of
a -valued 1-form – the vielbein
a -valued 1-form – the spin connection
a spin-representation valued 1-form – the spinor
a 3-form .
These are identified with the fields of 11-dimensional supergravity, respectively:
the graviton
the gravitino
the supergravity C-field .
By realizing this data as components of a Lie 3-algebra valued connection (more or less explicitly), the D’Auria-Fré-formalism achieves some conceptual simplication of
the construction of supersymmetric supergravity action functionals;
the determination of the corresponding classical equations of motion.
Originally D’Auria and Fré referred to commutative semifree dgas as Cartan integrable systems. Later the term free differential algebra, abbreviated FDA was used instead and became popular. Nowadays much of the literature that studies commutative semifree dgas in supergravity refers to them as “FDA”s. One speaks of the FDA approach to supergravity .
But strictly speaking “free differential algebra” is a misnomer: genuinely free differential algebras are pretty boring objects. Crucially it is only the underlying graded commutative algebra which is required to be free as a graded commutative algebra in that it is a Grassmann algebra on a graded vector space . The differential on that is in general not free, hence the more precise term semifree dga .
In fact, when is concentrated in non-positive degree (so that is concentrated in non-negative degree) the differential on encodes all the structure of an ∞-Lie algebroid on . If is concentrated in negative degree the differential encodes the structure of an ∞-Lie algebra on . This interpretation of semifree dgas in Lie theory is the key to our general abstract reformulation of the D’Auria-Fré-formalism.
Already D’Auria and Fré themselves, and afterwards other authors, have tried to better understand the intrinsic conceptual meaning of their dg-algebra formalism that happened to be so useful in supergravity:
The idea arose and then became popular in the “FDA”-literature that the D’Auria-Fré-formalism should be about a concept called soft group manifolds. This is motivated by the observation that by means of the dg-algebra formulation the fields in supergravity arrange themselves into systems of differential forms that satisfy equations structurally similar to the Maurer-Cartan forms of left-invariant differential forms on a Lie group – except that where the ordinary Maurer-Cartan form has vanishing curvature (= field strength) these equations for supergravity fields have a possibly non-vanishing field strength. It is proposed in the “FDA”-literature that these generalized Maurer-Cartan equations describe generalized or “softened” group manifolds.
However, even when the field strengths do vanish, the remaining collection of differential forms does not constrain the base manifold to be a group. Rather, if the field strengths vanish we have a natural interpretation of the remaining differential form data as being flat ∞-Lie algebroid valued differential forms, given by a morphism
from the tangent Lie algebroid of the base manifold to the ∞-Lie algebra encoded by the semifree dga in question. In fact, applying the functor from ∞-Lie algebroids to dg-algebras given by forming Chevalley-Eilenberg algebras, the above morphism turns into a dg-algebra morphism
to the deRham dg-algebra of (which we denote by the same letter, , in a convenient abuse of notation).
Since is semifree, this is a map of graded vector spaces
together with a constraint that the morphism respects the differentials on and on . Such a morphism of graded vector spaces in canonically identified with a -valued differential form (recall that is a graded vector space)
and the aforementioned constraint is precisely the Maurer-Cartan-like equation that is known from left-invariant 1-forms on a Lie group. In fact, for a Lie group with Lie algebra there is a canonical morphism
whose image is precisely the left-invariant 1-forms on the Lie group and whose respect for the differentials is precisely the ordinary Maurer-Cartan equation.
To see the role of group manifolds for more general morphisms
one has to apply Lie integration of the ∞-Lie algebroid morphism to a morphism of ∞-Lie groupoids
where is the path ∞-groupoid and where is the delooping of Lie in-group that integrates the Lie n-algebra . Such morphisms are the integrated version of flat ∞-Lie algebroid valued differential forms.
The ∞-Chern-Weil theory of connections on ∞-bundles is about
the generalization of such flat form data to ∞-Lie algebroid valued differential forms with curvature.
the generalization from globally defined differential form data – which are connections on trivial principal ∞-bundles – to connections on arbitrary principal ∞-bundles.
The D’Auria-Fré-formalism – after this re-interpretation – is about the first of these points. So as an immediate gain of our reformulation of D’Auria-Fré-formalism in terms of connections on ∞-bundles we obtain, using the second of these points, a natural proposal for a formulation of supergravity field configurations that are possibly globally topologically nontrivial. Physicists speak of instanton solutions.
In fact, the ∞-Lie theory-reformulation exhibits the D’Auria-Fré-formalism as being secretly the realization of supergravity as a higher gauge theory.
It realizes supergravity as an example for a nonabelian higher gauge theory in that a supergravity field configuration is not realizable as a cocycle in ordinary differential cohomology as in ordinary abelian higher gauge theory (see there) but as a nonabelian connection on an ∞-bundle.
We have a sequence of ∞-Lie algebra extensions
supergravity Lie 6-algebra supergravity Lie 3-algebra super Poincare Lie algebra
…
The base space on which a supergravity field is a super Lie -algebra valued connection on an ∞-bundle is a supermanifold.
In particular, for constructing the action functional of supergravity we want to locally look like super Minkowski space.
A local field configuration on a supermanifold in the classical field theory is a morphism
from the tangent Lie algebroid to the inner-derivation Lie 4-algebra , defined as the formal dual of the Weil algebra of ). So dually this is a morhism of dg-algebras from the Weil algebra to the deRham dg-algebra of :
This is ∞-Lie algebroid valued differential form data with ∞-Lie algebroid valued curvature that is explicitly given by:
connection forms / field configuration
– the spin connection (part of the graviton field)
– a differential 3-form (the supergravity C-field)
curvature forms / field strengths
- the torsion
- the Riemann curvature
– the covariant derivative of the spinor
– the 4-form field strength
A gauge transformation of a field configuration
is a diagram
Given a 1-morphism in , represented by -valued forms
consider the unique decomposition
with the horizontal differential form component and the canonical coordinate.
We call the gauge parameter . This is a function on with values in 0-forms on for an ordinary Lie algebra, plus 1-forms on for a Lie 2-algebra, plus 2-forms for a Lie 3-algebra, and so forth.
We describe now how this enccodes a gauge transformation
The condition that all curvature characteristic forms descend to in that completes to a diagram
is solved by requiring all components
of the curvature forms to vanish when evaluated on the vector field along .
By the nature of the Weil algebra we have
so that this condition is a system of ordinary differential equations of the form
where the sum is over all higher brackets of the ∞-Lie algebra .
Define the covariant derivative of the gauge parameter to be
In this notation we have
the general identity
the horizontality constraint or second Ehresmann condition
This is known as the equation for infinitesimal gauge transformations of an -Lie algebra valued form.
By Lie integration we have that – and hence – defines an element in the ∞-Lie group that integrates .
The unique solution of the above differential equation at for the initial values we may think of as the result of acting on with the gauge transformation .
In the formulation here the fields of supergravity are modeled by super differential forms on a supermanifold , and this very fact serves to make local supersymmetry manifest, i.e., serves to model geometry by higher supergeometric higher Cartan geometry.
But the actual fields of supergravity are supposed to be fields on actual spacetime (an ordinary smooth manifold) . Hence one is to impose a constraint that ensures that the super differential forms used on are uniquely determined by their restriction to ordinary differential forms on . This constraint is called rheonomy (Castellani-D’Auria-Fré 91, vol 2, section III.3.3), alluding to the idea that the constraints allow the field data to “flow” from spacetime to the super spacetime .
The idea here is analogous (Castellani-D’Auria-Fré 91, vol 2, p. 660, Fré-Grassi 08, p. 4) to how the Cauchy-Riemann equations impose the constraint for a function on the complex plane to be a holomorphic function and hence to be already fixed by its values on the real line .
In (Castellani-D’Auria-Fré, vol 2, section III.3.3) this idea is formalized by the constraint that for the given super--algebra connection as above, those components of the curvature forms which carry fermionic indices must be linear combinations of the components carrying no fermionic indices. (See also at L-∞ algebra valued differential forms – integration of transformation.)
This rheonomy constraint is equivalent to what elsewhere is called “superspace constraints”, see (AFFFTT 98, below (3.12)).
See also at rheonomy modality.
under construction
Let SuperFormalSmooth∞Groupoids.
(super-L-∞ algebra valued super differential forms)
Let be an super L-∞ algebra and let be a super ∞-groupoid (for instance a supermanifold or an extended super Minkowski spacetime).
Write
for the set of super-L-∞ algebra valued super differential forms on , hence of homomorphisms of differential graded-commutative superalgebras from the Weil algebra of
to the de Rham algebra of super differential forms on , which is given (see at geometry of physics – supergeometry this example) by
equipped with the differential graded-commutative superalgebra-structure induced by the action of (see at odd line there)
The restriction, as a linear map, of such a homomorphism
along the canonical inclusion of into the Weil algebra yields the curvature forms of .
(restriction of super-L-∞ algebra valued super differential forms to bosonic subspace)
Given SuperFormalSmooth∞Groupoids, write
for the inclusion of the underlying bosonic space (the counit morphism of the bosonic modality applied to ).
The pullback of the super differential forms in Def. along (5), is a function of the form
If is a supermanifold and is a coordinate chart with coordinates then restricted to this coordinate chart the pullback map (6) is given by evaluating super-differential forms at and
In this form this operation appears in Castellani-D’Auria-Fré 91, vol 2 (III.3.25).
(rheonomic set of super differential forms)
We may say that a subset
of super-Lie algebra valued super differential forms (Def. ) is rheonomic if on this subset the restriction to the bosoic subspace from Def. (hence the pullback of differential forms along ) is injective
hence if every super differential form
is, as an element of this subset, uniquely determined by its restriction to the bosonic submanifold .
More specifically, let now be an extended super Minkowski spacetime, with its super -extension of the corresponding super Poincare Lie algebra let be a V-manifold, and consider the subset
of globally defined Cartan connection-forms, meaning that their super vielbein component is constrained to be non-degenerate, establishing at each global point an linear isomorphism between its super tangent space and .
A sufficient condition for the subset (7) to be rheonomic(Def. ) is that the components of the curvature-forms with any odd-graded indices are linear combinations of the components of the curvature forms without odd-graded indices.
(Castellani-D’Auria-Fré 91, vol 2, (III.3.30))
Let
be a given form. Choosing any basis of , has components
We have to show, under the assumption that there existlinear maps
with
that is uniquely determined already by the component . For this it is sufficent to show that all component functions
and
may be expressed as functions of the .
We now first prove something weaker, namely that these functions are uniquely determined once we know not just but also .
It seems to me that this weaker statement is all that Castellani-D’Auria-Fré 91, vol 2, III.3.3 really provide, for notice that the last line of their (III.3.29) still depends on .
By the nilpotency of the odd-graded coordinates , we have that is a multilinear map in the .
Hence, by induction, assume that the -linear parts in the of is fixed by . It is then sufficient to show that also the -linear term is fixed.
This is evidently equivalent to the statement that all the derivatives of by any evaluated at are fixed.
The key point is that by the assumption that we have a Cartan connection, these derivatives are proportional to a sum of with a linear combination of the . But by assumption, (which a priori depends on data at ) is a linear combination of the curvatures with bosonic indices, and these are determined from the data at .
This is essentially the argument in Castellani-D’Auria-Fré 91, vol 2, (III.3.29)-(III.3.31), except that I have added the inductive argument, which seems necessary to really conclude beyond first order in ther odd coordinates.
This shows that satisfies well-formed differential equations in the .
To conclude, we hence need to see that we have sufficient boundary data on fixed to have the solution to this differential equation be unique.
Now the boundary data for is clearly , and if the differential equations did not also depend on this would be the end of the story.
We do not know the analogous boundary data , since all of is forgotten when restricting to . But we do have other boundary conditions on …
this is the argument I am adding in order to patch what seems to be a gap in Castellani-D’Auria-Fre
… namely since is the coefficient of , we may/should constrain it to be independent of the corresponding coordinate , for it had a dependence on this coordinate, this would disappear as we form .
Hence our total boundary conditions are
(no sum over ). Since we started with a solution to these differential equations, which we are trying to reconstruct, there is no issue here of integrating these differential equations. The only question is if these are sufficient to uniquely nail down that solution which we do know exists. Just by counting variables and conditions (which should be independent conditions) this should be the case.
(…)
A Chern-Simons element of an ∞-Lie algebra defines an ∞-Chern-Simons theory action functional on the space of -∞-Lie algebra-valued differential forms.
The major statement/claim is that all the supergravity equations of motion specify just precisely those super--connections – satisfying their Bianchi identities– which are rheonomic.
We discuss how actional functionals for supergravity theories are special cases of this.
In first-order formulation of gravity where the field of gravity is encoded in a vielbein and a spin connection , the Einstein-Hilbert action takes the Palatini form
where are the components of the curvature of and
is the signature of the index-permutation.
If and are components of an ∞-Lie algebroid-valued form then such a Palatini term is of the form as may appear in a Chern-Simons element
on . We now discuss, following D’Auria-Fré, how the action functionals of supergravity are related to ∞-Chern-Simons theory for Chern-Simons elements on certain super -Lie algebroids.
We discuss a system of equations that characterizes a necessary condition on Chern-Simons elements in the Weil algebra . This condition is called the cosmo-cocycle condition in (DAuriaFre).
To do so, we work in a basis of . Let be the corresponding shifted basis of . Write for the structure constants in this basis, so that the differential in the Weil algebra acts as
Write a general element in as
where .
The condition that has no terms linear in the curvatures is equivalent to the system of equations
for all .
In DAuriaFre p. 9 this system of equations is called the cosmo-cocycle condition .
This follows straightforwardly from the definition of the Weil algebra-differential :
We have , where . So
Here the first term contains no curvatures, while the second is precisely linear in the curvatures.
Moreover, by the Bianchi identity we have
Therefore the condition that all terms in that are linear in in vanish is
For comparison with DAuriaFre notice the following:
there all elements happen to be in even degree. Therefore the extra sign that we display does not appear.
the term that we write is there equivalently expressed as
(…)
(…)
Let be the supergravity Lie 6-algebra.
The Weil algebra:
(…)
The Bianchi identity
The element that gives the action is
This is DAuriaFre, page 26.
The first term gives the Palatini action for gravity.
The last terms is the Chern-Simons term for the the supergravity C-field.
The second but last two terms are the cocycle .
The term appearing here (the two terms containing no curvature) are -exact: there is a modification of this element by a -exact term for which the cocycles vanish, (DAuriaFre, page 27 and CastellaniDAuriaFre (III.8.136)). It follows that in particular is -closed. So with the above discussion of the “cosmo-cocycle”-condition the results given in DAuriaFre imply that has no 0-ary and no unary terms in the curvatures.
We find that the -differential of this Lagrangian term is
This fails to sit in the shifted generators by the terms coming from the translation algebra. For the degree-3 element however it does produce the expected term .
The formulation of supergravity of supermanifolds and the relevance of the Bianchi identities originates in
R. Grimm, Julius Wess, Bruno Zumino, A complete solution of the Bianchi identities in superspace with supergravity constraints, Nuclear Phys. B152 (1979), 255–265.
Julius Wess, Bruno Zumino, Superspace formulation of supergravity, Phys. Lett. B66 (1977), 361–364.
The use in this context of super L-∞ algebras in their formal dual incarnation semifree super-graded commutative dg-algebras was suggested originally in
The original articles that introduced specifically the D’Auria-Fré-formalism are
Riccardo D'Auria, Pietro Fré Tullio Regge, Graded Lie algebra, cohomology and supergravity, Riv. Nuov. Cim. 3, fasc. 12 (1980) (spire)
Riccardo D'Auria, Pietro Fré, Geometric Supergravity in D=11 and its hidden supergroup, Nuclear Physics B201 (1982) 101-140 (doi:10.1016/0550-3213(82)90376-5, errata)
Leonardo Castellani, Pietro Fré, F. Giani, K. Pilch, Peter van Nieuwenhuizen, Gauging of supergravity?, Annals of Physics Volume 146, Issue 1, March 1983, Pages 35–77
The standard textbook monograph on supergravity in general and this formalism is particular is
Leonardo Castellani, Riccardo D'Auria, Pietro Fré, Supergravity and Superstrings - A Geometric Perspective, World Scientific (1991)
Pietro Fré, Gravity, a Geometrical Course: Volume 2: Black Holes, Cosmology and Introduction to Supergravity, Springer 2012
Review:
Leonardo Castellani, Supergravity in the group-geometric framework: a primer (arXiv:1802.03407)
Riccardo D'Auria, Geometric supergravity (arXiv:2005.13593) in: Leonardo Castellani, Anna Ceresole, Riccardo D'Auria, Pietro Fré (eds.): Tullio Regge: An Eclectic Genius, World Scientific 2019 (doi:10.1142/11643)
Leonardo Castellani, Group manifold approach to supergravity, in: Handbook of Quantum Gravity, Springer (2023) [arXiv:2211.04318]
Discussion of gauged supergravity in this way is in
The interpretation of the D’Auria-Fré-formulation as identifying supergravity fields as ∞-Lie algebra valued differential forms is in
The Lie integration of that to genuine principal ∞-connections is in
The super L-∞ algebras that govern the construction are interpreted in the higher gauge theory of an ∞-Wess-Zumino-Witten theory description of the Green-Schwarz sigma-model-type -branes in
Apart from that the first vague mention of the observation that the “FDA”-formalism for supergravity is about higher categorical Lie algebras (as far as I am aware, would be grateful for further references) is page 2 of
An attempt at a comprehensive discussion of the formalism in the context of cohesive (∞,1)-topos-theory for smooth super ∞-groupoids is in the last section of
To compare D’Auria-Fre with our language here, notice the following points in their book
The statement that a supergravity field is a morphisms or dually a morphism out of the Weil algebra of the supergravity Lie 3-algebra or similar is implicit in (but it is evident, comparing with the formulas at Weil algebra) – notice that these authors call here a “soft form”.
What we identify as gauge transformations and shifts by the characterization of curvature forms on the cylinder object is their equation (I.3.36).
Here are some more references:
Pietro Fré, M-theory FDA, twisted tori and Chevalley cohomology (arXiv)
Pietro Fré, Pietro Antonio Grassi, Pure spinors, free differential algebras, and the supermembrane (arXiv:0606171)
Pietro Fré, Pietro Grassi, Free differential algebras, rheonomy, and pure spinors (arXiv:0801.3076)
Discussion in this formalism of the Green-Schwarz action functional for the M2-brane sigma-model with a target space 11-dimensional supergravity background is in
Gianguido Dall'Agata, Davide Fabbri, Christophe Fraser, Pietro Fré, Piet Termonia, Mario Trigiante, The singleton action from the supermembrane, Nucl.Phys.B542:157-194,1999, (arXiv:hep-th/9807115)
Pietro Fré, Pietro Antonio Grassi, Pure Spinors, Free Differential Algebras, and the Supermembrane, Nucl. Phys. B 763:1-34, 2007 (arXiv:hep-th/0606171)
Relation to pure spinor-formalism:
Last revised on April 5, 2023 at 08:36:18. See the history of this page for a list of all contributions to it.