nLab D=12 supergravity

Redirected from "12d supergravity".
Contents

Context

Gravity

Physics

physics, mathematical physics, philosophy of physics

Surveys, textbooks and lecture notes


theory (physics), model (physics)

experiment, measurement, computable physics

Super-Geometry

Fields and quanta

fields and particles in particle physics

and in the standard model of particle physics:

force field gauge bosons

scalar bosons

matter field fermions (spinors, Dirac fields)

flavors of fundamental fermions in the
standard model of particle physics:
generation of fermions1st generation2nd generation3d generation
quarks (qq)
up-typeup quark (uu)charm quark (cc)top quark (tt)
down-typedown quark (dd)strange quark (ss)bottom quark (bb)
leptons
chargedelectronmuontauon
neutralelectron neutrinomuon neutrinotau neutrino
bound states:
mesonslight mesons:
pion (udu d)
ρ-meson (udu d)
ω-meson (udu d)
f1-meson
a1-meson
strange-mesons:
ϕ-meson (ss¯s \bar s),
kaon, K*-meson (usu s, dsd s)
eta-meson (uu+dd+ssu u + d d + s s)

charmed heavy mesons:
D-meson (uc u c, dcd c, scs c)
J/ψ-meson (cc¯c \bar c)
bottom heavy mesons:
B-meson (qbq b)
ϒ-meson (bb¯b \bar b)
baryonsnucleons:
proton (uud)(u u d)
neutron (udd)(u d d)

(also: antiparticles)

effective particles

hadrons (bound states of the above quarks)

solitons

in grand unified theory

minimally extended supersymmetric standard model

superpartners

bosinos:

sfermions:

dark matter candidates

Exotica

auxiliary fields

Contents

Idea

There is a sensible theory of supergravity in a total of 12 spacetime dimensions. Even though this requires an exotic non-Lorentzian signature of (10,2)(10,2) (hence with a “2-dimensional time”) it has been argued that this is a better starting point for obtaining low-dimensional supergravity theory by KK-compactification, since it yields some lower-dimensional theories that are missed when starting with 11-dimensional supergravity, notably type IIB supergravity in 10 dimensions, hence relates to F-theory as 11-dimensional supergravity relates to M-theory (e.g. Nishino 97b, Hewson 97). (A theory in (9,3)(9,3) signature has also been proposed in (Kriz 05).)

It is an oft-repeated folklore that the highest number of spacetime dimensions for supergravity to make sense is 11, realized by 11-dimensional supergravity. However, there are some assumptions that go into this conclusion. First of all, the argument goes that after KK-compactification to 4-dimensions there must not appear supermultiplets with mass-less fields of spin >2\gt 2, since another folklore argument states that quantum field theory in 3+13+1 dimensions with fields of spin larger than 2 is inconsistent.

(This in turn needs further qualification: Consistent quantum field theory with an infinite tower of higher spin fields is consistent, this is called higher spin gauge theory arising as the vanishing string tension-limit of string field theory. Ever since this discovery, the modified folklore is that field theories with a finite number of higher spin fields is inconsistent.)

Since acting with a supersymmetry generator on elements of a supermultiplet increases spin by 1/2, this argument requires that there are at most (2(2))×2=8(2 - (-2)) \times 2 = 8 super charges in (3+1)d, hence corresponding to N=8 d=4 supergravity.

This, in turn, requires, by the rules of KK-compactification, that

  1. there be only a single supercharge in dimension 10+110+1, since the irreducible real spin representation of Spin(10,1)Spin(10,1) has real dimension 32, which branches as 3284\mathbf{32} \mapsto 8 \cdot \mathbf{4} under Spin(3,1)Spin(10,1)Spin(3,1) \hookrightarrow Spin(10,1);

  2. there cannot be any supercharge in dimension 11+111+1, since the irreducible real spin representation of Spin(11,1)Spin(11,1) has real dimension 64, which branches as 64164\mathbf{64} \mapsto 16 \cdot \mathbf{4} under Spin(3,1)Spin(11,1)Spin(3,1) \hookrightarrow Spin(11,1).

However, the second conclusion here is evaded by a change of spacetime signature: The irreducible real spin representation of Spin(10,2) still happens to be of dimension 32 and still branches as 3284\mathbf{32} \mapsto 8 \cdot \mathbf{4}.

Properties

The 2+12+1-brane in 10+210+2 dimensions

There is supposed to be a consistent fundamental super p-brane on 10+210+2-dimensional supergravity backgrounds, whose double dimensional reduction yields the M2-brane in 11-dimensional supergravity and further the superstrings not just of type IIA supergravity but also (?) of type IIB supergravity. The worldvolume of this p-brane has 4 spacetime dimensions with signature (2,2)(2,2). Therefore some authors refer to this as a “2+2”-brane, even though this does not mesh well with the naming convention of pp-branes in Lorentzian signature. Since Lorentzian pp-branes have (p+1)(p+1)-dimensional worldvolume, the systematic naming here would be “2+1”-brane.

See (Blencowe-Duff 88, section 7, Hewson-Perry 96, Nishino 97b)

References

General

On the 2+12+1-brane in 10+210+2 dimensions

On supergravity in 9+39 + 3 dimensions

In bosonic M-theory

On organizing all these variants inside bosonic M-theory and KK-reduction on Cayley planes to actual M-theory:

reviewed in:

Last revised on January 15, 2023 at 10:55:40. See the history of this page for a list of all contributions to it.