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6.7 Type IIA Supergravity in D = 10

253

6.7.2Field Equations of Type IIA Supergravity in the String Frame

As usual the rheonomic parameterizations of the supercurvatures imply, via Bianchi identities, a certain number of constraints on the inner components of the same curvatures which can be recognized as the field equations of type IIA supergravity. In [29] the authors derived the bosonic part of these field equations in two steps: first they performed the Einstein frame dimensional reduction on a circle of the field equations of D = 11 supergravity. Then they applied the Weyl transformation which relates the Einstein frame to the string frame:

V(E)a = V(S)a eϕ/4

(6.7.38)

Obviously they could have obtained the same result directly from the Bianchi identities in the string frame, yet this would have been much more laborious.

In any case the result is the following one. There is an Einstein equation of the following form:

 

 

 

 

Rab = T7ab(f ) + T7ab(G2) + T7ab(H ) + T7ab(G4)

(6.7.39)

where the stress-energy tensor on the right hand side are defined as

 

 

Tab(f )

 

 

Da Dbϕ

 

 

9 Da ϕDbϕ

 

ηab

6

ϕ

 

 

9 D m

ϕDmϕ

(6.7.40)

 

 

= −

 

 

 

 

+

8

 

 

 

1

 

 

+

5

 

 

 

 

 

 

7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

T

(G )

 

exp 2ϕ

 

G

 

Gby ηab

 

 

 

 

 

 

 

 

 

 

 

 

(6.7.41)

7ab

2

=

 

[

]1 ax

 

9

 

 

 

 

 

 

1

ηabHxyzH xyz

(6.7.42)

Tab(H )

= −

exp

3 ϕ 8 Haxy Hbwt ηxw ηyt

8

7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Tab(G4)

 

exp 2ϕ 6Gax1x2x3 Gby1y2y3 ηx1y1 ηx2y2 ηx3y3

 

2

ηabGx1...x4 G x1...x4

 

 

=

 

[

]

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

 

 

7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(6.7.43)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Next we have the equations for the dilaton and the Ramond 1-form:

 

 

 

 

3

 

 

 

 

 

0

= ϕ 2fa f a +

 

exp[2ϕ]G x1x2 Gx1x2

 

 

2

3

ϕ H x1x2x3 Hx1x2x3 (6.7.44)

 

+

2 exp[2ϕ]G x1x2x3x4 Gx1x2x3x4 +

4 exp

 

 

3

 

 

 

 

 

 

3

 

4

 

0

= DmG ma

5

f mGma + 3G ax1x2x3 Hx1x2x3

 

(6.7.45)

 

 

 

3

 

and the equations for the NS 2-form and for the RR 3-form:

0 = DmH mab

2

f mHmab

 

 

 

 

 

 

 

 

 

3

 

 

 

 

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