Eur. Phys. J. C (2019) 79:668
https://doi.org/10.1140/epjc/s10052-019-7182-9
Regular Article - Theoretical Physics
Rotating charged AdS solutions in quadratic f (T ) gravity
A. M. Awad1,2,a , G. G. L. Nashed3,4,b , W. El Hanafy3,4,c
1 Department of Physics, School of Sciences and Engineering, American University in Cairo, P.O. Box 74, AUC Avenue New Cairo, Cairo, Egypt
2 Department of Physics, Faculty of Science, Ain Shams University, Cairo 11566, Egypt
3 Centre for Theoretical Physics, the British University in Egypt, El Sherouk City 11837, Egypt
4 Egyptian Relativity Group, Cairo University, Giza 12613, Egypt
Received: 8 April 2019 / Accepted: 31 July 2019 / Published online: 8 August 2019
© The Author(s) 2019
Abstract We present a class of asymptotically anti-de Sitter charged rotating black hole solutions in f (T ) gravity
in N -dimensions, where f (T ) = T + αT 2 . These solutions are nontrivial extensions of the solutions presented
in Lemos (Phys Lett B 353:46–51. arXiv:gr-qc/9404041,
1995) and Awad (Class Quantum Gravity 20:2827–2834.
arXiv:hep-th/0209238, 2003) in the context of general relativity. They are characterized by cylindrical, toroidal or
flat horizons, depending on global identifications. The static
charged black hole configurations obtained in Awad et al.
(JHEP 07:136. arXiv:1706.01773, 2017) are recovered as
special cases when the rotation parameters vanish. Similar to Awad et al. (JHEP 07:136. arXiv:1706.01773, 2017)
the static black holes solutions have two different electric
multipole terms in the potential with related moments. Furthermore, these solutions have milder singularities compared
to their general relativity counterparts. Using the conserved
charges expressions obtained in Ulhoa and Spaniol (Int J Mod
Phys D 22:1350069. arXiv:1303.3144, 2013) and Maluf and
Ulhoa (Gen Relativ Grav 41:1233–1247. arXiv:0810.1934,
2009) we calculate the total mass/energy and the angular
momentum of these solutions.
1 Introduction
In the last two decades there has been a growing interest in
gravitational solutions with cosmological constant in general relativity (GR) and its extensions. This interest has been
generated by seminal observational and theoretical breakthroughs, namely, the discovery of cosmic acceleration [6,7]
and the gauge/gravity dualities [8]. Black hole solutions play
a very important role in unraveling several classical and quana e-mail:
[email protected]
b e-mail:
[email protected]
tum mechanical aspects of the underlying gravitational theory. Therefore, it is viewed as an important tool to study various extensions of GR. Contrary to asymptotically flat black
holes, asymptotically de Sitter (dS) and anti-de Sitter (AdS)
black hole solutions possess more than one type of horizon
topology. They could have spherical, hyperbolic, or flat horizons. dS and AdS black hole solutions have been obtained
and studied in GR extensively, as well as teleparallel gravities, please see [1,2,9–19], for diverse black hole solutions.
Since the confirmation of the above cosmological observations there have been several proposed extensions of GR
which are based on Riemannian as well as other types
of geometries. Gravitational theories based on Riemannian
geometry have been extended through f (R) gravitational
theory which was proposed in [20,21]. In such a theory,
the Ricci scalar R is replaced by an arbitrary function
f (R) in Einstein-Hilbert action. Other extensions consider
a Lagrangian density on the form of f (R, T ) where T the
trace of the energy-momentum tensor of the matter component [22], or some f (R, G) where G is Gauss-Bonnet scalar
[23–27]. Different approach, however, has been developed
within Weitzenböck geometry by introducing the teleparallel torsion scalar, T , as the Lagrangian density instead of the
Ricci scalar, that is the teleparallel equivalent of general relativity (TEGR) theory. Motivated by the f (R) gravity extension, TEGR has been generalized to f (T ) gravity by replacing T by an arbitrary function f (T ) [28]. The f (T ) gravity is
considered to be one of the simplest extensions of GR, since
its field equations are still second order [29–31] in spite of
having arbitrary torsion scalar terms. Although there is an
equivalence between GR and TEGR on the field equations
level, their generalizations f (R) and f (T ) are not equivalent.
In general, finding an exact nontrivial black hole solution
in the above extensions, including f (T ) gravity, is not an easy
task [3,32–38]. In this work, we present a rotating black hole
in all dimensions within Maxwell- f (T ) theory with a nega-
c e-mail:
[email protected]
123
668 Page 2 of 8
tive cosmological constant, where f (T ) = T + αT 2 . These
asymptotically AdS black holes are characterized by cylindrical, toroidal or flat horizons depending on the global identifications of some coordinates. These solutions can be constructed from coordinate transformations which are allowed
locally on a manifold but not globally [39]. They are the f (T )
analogue of the solutions found in GR by Lemos [1] and their
generalizations in higher dimensions that were introduced by
one of us in [2]. The charged static configurations obtained
in [3] are recovered in the limit of vanishing rotation parameters. These interesting black hole solutions have two different
electric multipole terms in the electric potential with related
multipole moments. In addition, they have milder singularities at r = 0, similar to that of the static solutions obtained
in [3], compared to Reissner Nordström solutions in GR.
We calculate the energy and the angular momentum of the
black hole using the conserved quantities in the framework
of teleparallel gravity.
This work is arranged as follow: In Sect. 2, a brief account
of f (T ) gravitational theories are provided in addition to
the previous solutions derived in [3] within the framework
of f (T ) gravitational theory. In Sect. 3, charged rotating N
dimensional exact solutions are derived. These solutions have
monopoles and quadrupole moments which are not independent, in addition of being asymptotically AdS. In Sect. 4,
we calculate the energy and angular momentum of these
solutions. In the final section we comment on some physical aspects of these black hole solutions.
2 Maxwell- f (T ) gravity
2.1 Teleparallel geometry
A Vielbein space can be defined as a pair (M, ea ), where
M is an N -dimensional differentiable manifold and the set
{ea } contains N independent vector fields defined globally
on M, this set at point p is the basis of its tangent space
T p M. Because of the independence of ea , the determinant
e ≡ det(ea μ ) is nonzero. The vielbein vector fields satμ
isfy ea μ ea ν = δν and ea μ eb μ = δab , where δ is the Kronecker tensor. Thus, we can construct an associated (pseudoRiemannian) metric and its inverse, respectively, for any
set of basis gμν ≡ ηab ea μ eb ν , g μν = ηab ea μ eb ν , where
ηi j = (−, +, +, +, · · · ) is the metric of N -dimensions
√
Minkowski spacetime. Also, it can be shown that e = −g,
where g ≡ det(g). Thus, we go further to define the symmetric Levi-Civita connection. In this sense, the vielbein
space is a pseudo-Riemannian as well. However, if we decide
not to use curvature as the basic description of gravity, we
may begin with the vielbein vector fields as the fundamental field variables. Then, we define the nonsymmetric linear (Weitzenböck) connection [40] W α μν ≡ ea α ∂ν ea μ =
123
Eur. Phys. J. C (2019) 79:668
−ea μ ∂ν ea α . This connection is characterized by the property that ∇ν ea μ ≡ ∂ν ea μ + W μ λν ea λ ≡ 0, where the covariant derivative ∇ν is associated to the Weitzenböck connection. This nonsymmetric connection uniquely determines the
teleparallel geometry, since the vielbein vector fields are parallel with respect to it. Indeed, the Weitzenböck connection is curvature free, but it has a non vanishing torsion
T α μν = W α νμ − W α μν = ei α [∂μ ei ν − ∂ν ei μ ]. Now we
can go directly to construct the teleparallel torsion scalar
T = T α μν Sα μν ,
(1)
Sα μν
where
tensor
:=
μν the superpotential
is defined as
μ βν
1
ν T βμ
K
and
the
Contortion
tensor
+
δ
T
−
δ
α
β
β
α
α
2
is K αμν = 21 Tναμ + Tαμν − Tμαν .
2.2 The theory
We take the action of the f (T )-Maxwell theory in N dimensional for asymptotically (Anti)-de-Sitter spacetimes
as
1
Sg + Sem =
d N x |e| ( f (T ) − 2 )
2κ
1
−
(2)
d N x |e|F ∧ F,
2κ
−2)
is the N -dimensional cosmologwhere = − (N −1)(N
2l 2
ical constant in N dimensions, l is the length scale of AdS
spacetime, κ is a dimensional constant which can be related to
the Newton constant G N by κ = 2(N − 3) N −2 G N , where
2π (N −1)/2
N −2 = ([N −1]/2) is the volume of (N − 2)-dimensional
unit sphere and function being the argument that depends
on the dimension of the spacetime.1,2 Also, in the Maxwell
action, F = dA, with A = Aμ d x μ being the gauge potential
1-form [3,37].
Varying the action (2) with respect to the vielbein and the
vector potential Aμ , one gets, respectively, the field equations
[29]
Iν μ = Sμ ρν ∂ρ T f T T
+ e−1 ea μ ∂ρ eea α Sα ρν − T α λμ Sα νλ f T
δμν
κ em
(N − 1)(N − 2)
+ T ν μ,
f +
−
2
4
l
2
√
∂ν
−g F μν = 0,
(3)
em
)
∂ f (T )
ν
where f := f (T ), f T := ∂ f∂(T
T , f T T := ∂ T 2 and T μ
is the energy momentum tensor of the electromagnetic field
which is given by [37]
2
1 For N = 4, one can recover 2(N − 3)
N −2 = 8π G 4 .
2 The spacetime indices are given by μ, ν · · · and the SO(3,1) indices
are given by a, b, · · · in which all of them run from 0
to 3. The
Latin indices i, j, · · · are denote to the SO(3,1) spatial components.
Eur. Phys. J. C (2019) 79:668
em
ν
T μ = Fμα F
να
Page 3 of 8 668
where = d
dr . The general N-dimensional solutions with
flat horizons of the Maxwell- f (T ) theory, where f (T ) =
T + αT 2 of the above differential equations takes the form
[3]
1
− δμ ν Fαβ F αβ .
4
2.3 AdS charged black holes with flat horizons
In a previous work [3] we have introduced the following
diagonal vielbein which describes a static configuration in
N -dimensions with the coordinates (t, r , φ1 , φ2 , . . ., φn , z 1 ,
z 2 , . . ., z k , k = 1, 2, . . ., N − n − 2)
1
i
, r, r, r · · · ,
(4)
eμ =
A(r ), √
B(r )
where 0 ≤ r < ∞, −∞ < t < ∞, 0 ≤ φn < 2π
and −∞ < z k < ∞. The functions A(r ) and B(r ) are
two unknown functions of the radial coordinate r . Thus, the
spacetime which can be generated by (4) is
ds 2 = −A(r )dt 2 +
1
dr 2
B(r )
N −n−2
n
+r
dφi2 +
2
i=1
k=1
dz k2
l2
.
(5)
Substituting from Eq. (4) into Eq. (1), we evaluate the torsion
scalar as3
B
A B
+ (N − 2)(N − 3) 2 .
(6)
rA
r
Using the N-dimensional spacetime of Eq. (4) with Eq. (6)
and the vector potential A = (r )dt, we obtain the following
Eq. (3):
T = 2(N − 2)
2(N − 2)B f T T T
r
(N − 2) f T [2(N − 3)AB + r B A + r AB ]
+
r2 A
22 (r )B
= 0,
− f +2 +
A
I r r = 2T f T + 2 − f
22 (r )B
= 0,
+
A
I φ1 φ1 = Iφ2 φ2 = · · · Iφn φn = Iz 1 z 1
Itt =
= Iz 2 z 2 · · · = Iz k z k =
fT
+ 2 2 2r 2 AB A
2r A
f T T [r 2 T + (N − 2)(N − 3)B]T
(N − 2)r
− r 2 B A2 + 4(N − 3)2 A2 B
+ 2(2N − 5)r AB A + r 2 A A B + 2(N − 3)r A2 B
− f +2
−
22 (r )B
= 0,
A
3 For abbreviation we will write A(r ) ≡
d A
d2 A
d2 B
dB
dr ,A ≡ dr 2 ,B ≡ dr 2 and B ≡ dr .
B(r ) ≡ B,
ef f −
m
+
N −3
(8)
1
where e f f = 6(N −1)(N
−2)|α| , m is the mass parameter, q is
the charge parameter and (r ) is the electric potential which
defines the vector potential A = (r )dt. As it is clear from
Eq. (8), that the potential (r ) depends on a monopole and
quadrupole moments. By setting q = 0 both momenta vanish
and we get a non-charged solution. It is worth mentioning that
the solution (8) has been derived for the quadratic polynomial
1
.
f (T ) theory in the presence of the constraint
= 24α
Consequently, one expects the model parameter to be α < 0,
since the cosmological constant is negative. The reason of the
1
is as follows: If one chooses an ansatz for
constraint = 24α
the charged solution in which the functions A(r ) and B(r ) are
equal then one gets constant potential, i.e., a trivial potential
for a charged solution! In order to avoid this trivial potential,
we choose A(r ) = C(r )B(r ). In this case the potential will
not be trivial, but A(r ) and B(r ) are neither unique nor in
closed form. For example, for the 5-dimensional uncharged
solution, (r ) = 0, we have C(r ) = const. and
√
c1
[1 ± 1 − 24α ]r 2
+ 2
A(r ) =
72α
r
which shows that A(r ) is not unique. An extra complication is
obtained when the potential is not constant, in this case, A(r )
and B(r ) can not be expressed in a closed form. Choosing
1
leave the solution unique and in a closed form.
= 24α
Before closing this section, we note that the black hole
solution at hand cannot be considered as a special case of
the cubic polynomial f (T ) gravity which has been studied
in [41]. In the later, the solution has been obtained under
a specific constraint whereas the coefficient of cubic term
cannot be made to vanish.
3 AdS charged rotating black holes with flat horizons
(7)
A,
3(N − 3)q 2
r
(N − 2)r 2(N −3)
√
2 6 |α|(N − 3)3 q 3
+
,
(2N − 5)(N − 2)r 3N −8
√
−2
(N − 3)q 6 |α|
,
B(r ) = A(r ) 1 +
r N −2
√
q
(N − 3)2 q 2 6 |α|
(r ) = N −3 +
,
r
(2N − 5)r 2N −5
A(r ) = r 2
A ≡
One way to add an angular momentum for the above solution
in four dimensions4
4 It is well known, even in GR, that the addition of cosmological con-
stant might produce different types of rotating black holes among them
123
668 Page 4 of 8
ds 2 = −A(r )dt 2 +
Eur. Phys. J. C (2019) 79:668
1
dz 2
dr 2 + r 2 dφ 2 + 2 .
B(r )
l
(9)
We follow the procedure developed in [1,2], applying the
transformations
ω
φ̄ = − φ + 2 t,
t¯ = t − ω φ.
(10)
l
We note that these transformations are allowed locally but
not globally on a manifold as will be clarified below. Thus
the spacetime (9) reads
2
dr 2
ds 2 = −A(r ) d t¯ − ωd φ̄ +
B(r )
2 r 2
r2
+ 4 ωd t¯ − l 2 d φ̄ + 2 dz 2 ,
l
l
where
ω2
:= 1 + 2 .
l
¯ ) = −(r ) ωi d φ̄i − d t¯ .
(r
j=1
Footnote 4 continued
is the class under consideration here, please see [13] for a discussion
on these types of rotating black holes.
123
2
n
ds = −A(r ) d t¯ −
ωi d φ̄
2
i=1
dr 2
r2
+
+ 4
B(r )
l
r2
− 2
l
n
n
i=1
2 r 2
ωi d t¯ − l 2 d φ̄i + 2 d 2
l
2
ωi d φ̄ j − ω j d φ̄i ,
(14)
i< j
where 0 ≤ r < ∞, −∞ < t < ∞, 0 ≤ φi < 2π ,
i = 1, 2, . . . , n and −∞ < z k < ∞, d 2 = dz k dz k
is the Euclidean metric on (N − n − 2)-dimensions and
k = 1, 2, . . . , N −3. We note that the static configuration (9)
can be recovered as a special case when the rotation parameters ω j are chosen to be vanished. These charged rotating
solutions do not correspond to any known solutions in GR
or TEGR since by sending α → 0 we do not get a well
defined tetrad or metric. Notice that upon setting the mass
√
√
√
⎛ √
⎞
A(r ) 0 −ω1 A(r ) −ω2 A(r ) · · · −ωn A(r ) 0 0 · · · 0
⎜
√1
0
0···
0
0 0 ··· 0⎟
0
⎜
⎟
B(r )
⎜ ω1 r
⎟
0
−r
0
·
·
·
0
0
0
·
·
·
0
⎜
⎟
2
⎜ ωl2 r
⎟
0
0
−r
·
·
·
0
0
0
·
·
·
0
⎜
⎟
2
l
⎜
⎟
.
.
.
.
.
.
.
.
⎜
=⎜
..
..
..
..
..
.. .. · · · .. ⎟
⎟,
⎜ ωn r
⎟
⎜
0
0
0···
−r
0 0 ··· 0⎟
⎜
⎟
l2
⎜
0
0
0
0···
0
r 0 ··· 0⎟
⎜
⎟
⎝
0
0
0
0···
0
0 r ··· 0⎠
0
0
0
0···
0
0 0 ··· r
where n = (N − 1)/2 is the number of rotation parameters
with y is the integer part of y, ω j are the rotation parameters
and is defined as
n
ωj2
.
:= 1 +
l2
(13)
We note that Eqs. (8) and (13) are also solutions of the stationary configuration (12). Since transformation (10) mixes compact and noncompact coordinates, it leaves the local properties of spacetime the same. However, it does change the
spacetime properties globally, c.f. [1]. On other words, the
vielbein (4) and (12) can be locally mapped into each other
but not globally [1,2]. One can show that the spacetime which
is generated by the vielbein (12) takes the form
(11)
According to Stachel [39] if the first Betti number of the
manifold is non-vanishing, which is the case for the equivalent Riemannian manifold of these solutions, there are no
global diffeomorphisms that can map one of these metrics
to the other, leaving the new manifold with an additional
parameter “ω”. Since in N dimensions we have more than
one rotation parameter, the construction of the rotating tetrad
or metric is not as obvious as the one rotation parameter case
as was shown in [2]. It requires the addition of other terms
which are not obtained by the above coordinate transformations. In the higher dimensional case the proposed form of
the tetrad for more than one rotation parameter is given by
ei μ
Also, the functions A(r ) and B(r ) are given by (8). In addition, the gauge potential takes the form
(12)
parameter m = 0 and the charge q = 0, the line-element
(14) reduces to the N -dimensional AdS metric in an unusual
coordinate system. One can easily check that the resulting boundary metric is indeed Minkowski through checking
the vanishing of its torsion components. Furthermore, this
shows that the whole metric in this limit (i.e., line-element
with m = 0 and the charge q = 0) is the AdS metric. In
the next section, we are going to study the main feature of
solution (12).
Eur. Phys. J. C (2019) 79:668
Page 5 of 8 668
4 Conserved charges
AdS spacetime from that of the solution. Therefore Eqs. (19)
and (28) take the form
d N −1 x |e|t 0a
,
(20)
Pa =
4.1 Four-momentum
Before we calculate the energy or total mass of these
black holes, let us follow [4] deriving the conserved fourmomentum for f (T ) gravity in few lines. Variation of the
action (2) with respect to the vielbein gives the field equations in the form
Sμ ρν ∂ρ T f T T
+ e−1 ea μ ∂ρ eea α Sα ρν − T α λμ Sα νλ f T
δμν
κ
(N − 1)(N − 2)
= − Tν μ ,
f +
−
4
l2
2
(15)
κ
∂ρ eS aνρ f T = |e| t aν + T aν ,
2
t aν =
2
κ
f T S bcν Tbc a −
δμν
4
f +
(16)
(N − 1)(N − 2)
l2
r eg
where the subscript “reg” stands for the regularized value of
the physical quantity.
Let us now calculate the energy related to the rotating
charged black holes given by Eq. (12). Using Eq. (19), it is
possible to derive the components that are necessary for the
calculations of energy in the form5 :
(N − 2)B
.
(21)
2r
(N − 2)[m − e f f r (N −1) ]
1
+ ...,
+
P0 = E =
3(N − 3)G N
r
(22)
S (0)(0)1 =
where Tν μ is the energy-momentum of the matter. Equation
(15) can be rewritten as
where
V
.
(17)
Taking the derivative of Eq. (16) with respect to x ν , we get
∂ν ∂ρ eS aνρ f T = 0 which leads to
κ
|e| t aν + T aν = 0.
∂ν
(18)
2
Equations (18) give the conserved N -momentum of f (T )
gravitational theory in the form
a
P =
d N −1 x|e|t 0a .
(19)
where n ≥ 1. expression of Eq. (19) takes the form of a
surface integral
2
Praeg :=
d N −2 x eS a0μ n μ f T
κ ∂V
2
−
d N −2 x eS a0μ n μ f T
,
(23)
Ad S
κ ∂V
where n μ is the normal vector to the surface ∂ V and AdS
means evaluating the second expression of Eq. (19) for pure
Anti-de-Sitter space. Using (23) in solution (12), we get
Er eg =
2(N − 2) M
,
3 (N − 3)
(24)
where the mass parameter is taken to be m = 2 G N M. As
expected, the black hole energy is fully characterized by its
mass.
4.2 Angular momentum
V
Equation (19) which defines the N -momentum of f (T ) gravity was derived before in [4]. This has been used, mostly,
to calculate energy for asymptotically flat spacetime background. However, the solutions (12) are asymptotically AdS.
Here we adopt the point of view of the authors in [42–45] to
calculate conserved quantities of a gravitational solution in
reference to a specific background spacetime. These backgrounds are naturally chosen as Minkowski spacetime for
asymptotically flat solutions and AdS or dS for asymptotically AdS or dS solutions. Furthermore, infinities due to the
asymptotic regions are canceled out in this subtraction prescription leaving the physical quantities finite. For example,
the total energy of an AdS black hole, measured by a stationary observer at very large radial distance, is considered to
be the difference in energy between the AdS black hole and
the AdS space itself. Therefore, in calculating the conserved
quantities, it is natural to subtract the contribution due to pure
Although there is a hamiltonian formulation in teleparallel equivalent of general relativity (i.e., f (T ) = T ) which
produces some known expressions for the conserved fourmomenta and angular momentum [5], there is no known
expression for angular momentum in f (T ) gravity. But since
the angular momentum is independent of the charge q, by
sending q → 0 we obtain a solution with constant torsion
scale T , since the scalar torsion is given by,
√
2q 6
−1
+ √ 3.
(25)
T =
6α
3 αr
A solution in f (T ) gravity with constant torsion scalars,
T = Tc , is equivalent to a solution in TEGR with constant
torsion, where T = f (Tc ). Therefore, one can use Maluf’s
5 The square parentheses in the quantities S (0)(0)1 refer to the tangent
components, i.e., S (0)(0)1 = e0 μ e0 ν S μν1 .
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668 Page 6 of 8
Eur. Phys. J. C (2019) 79:668
expression in [5] to calculate the angular momentum of our
solution in this limit. Following [5], the angular momentum
tensor can be written in terms of the superpotential S abc in
the following form
M aμc ≡ |e|eb μ S abc − S cab = |e| S aμc − S caμ
1
= − ∂ν {|e| [eaν ecμ − eaμ ecν ] }.
2
From Eq. (26) one can easily show that
∂μ M aμc = 0.
(26)
(27)
Using Eqs. (26) and (27) the conserved angular momentum
is given by
ab
d N −1 M a0b
L =
V
1
=−
d N −1 x∂ν {|e| [eaν eb0 − ea0 ebν ] }
κ V
1
d N −2 x n ρ |e| [eaρ eb0 − ea0 ebρ ],
(28)
=−
κ ∂V
where n ρ is the outward unit normal vector.
Now we are going to calculate the angular momentum
of solution (12) in the limit q → 0. For this aim we are
going to list the necessary components needed for these calculations. The non-vanishing components of the torsion tensor, T abc = ea μ eb ν ec ρ T μνρ , and the superpotential tensor,
S abc = ea μ eb ν ec ρ S μνρ , are
√
A B
(29)
,
2A
√
!n
ωa 2 δi j + ωi ω j
B
l 2 2 − a=1
T(N −i)(N − j)(1) =
, (30)
l 2 2 r
√
B
T N −n−!(N −n−2) k N −n−!(N −n−2) k (1) =
(31)
,
r
k=1
k=1
(N − 2)B
S(0)(0)1 =
(32)
,
2r
S(N −i)(1)(N − j)
√
!n
B l 2 2 − a=1
ωa 2 δi j + ωi ω j 2(N − 3)A + r A
=
,
4 Al 2 2 r
T(0)(1)(0) =
(33)
S N −n−!(N −n−2) k (1) N −n−!(N −n−2) k
k=1
k=1
√
B 2(N − 3)A + r A
.
=
4 Ar
(34)
Similar to the energy calculations, we are going to use the
background subtraction prescription to calculate the angular momentum of the black hole relative to the AdS space
background.
1
d N −1 xei μ e j ν |e|[(S μ0ν − S ν0μ )]r eg .
(35)
Li j = −
κ V
123
Using the above equation one gets
Ji |r eg =
ωi M
,
2 (N − 3)
(36)
where
Ji = i jk L jk .
(37)
As clear from the above equations that the angular momentum vanishes when the rotation parameters ωi vanish. In conclusion, under the constraint q → 0, Eqs. (24) and (36) show
that the black holes are characterized by their masses and
angular momenta.
5 Conclusions
In this work, we present a new class of charged rotating solutions in f (T ) theories in N dimensions. These solutions are
obtained for f (T ) = T + αT 2 , where the parameter α < 0.
It is worth to mention that these solutions cannot be considered as special cases of the solutions of the cubic polynomial
f (T ) gravity which have been recently studied in [41]. This is
because the later are obtained whereas the cubic contribution
is parameterized by an extra parameter which cannot be made
to vanish. One of the attractive features of the solutions at
hand is that their electric potential has related monopole and
quadrupole moments. The relation between these moments
is a result of demanding an asymptotically AdS solution. It is
intriguing to note that all these black holes have a singularity
at r = 0, which is milder than that of their corresponding solutions in TEGR or GR. The asymptotic behavior of
the Kretschmann invariant, the Ricci tensor squared, and the
Ricci scalar have the same form of the charged ones presented in [3], i.e. K = Rμν R μν ∼ r −2(N −2) , R ∼ r −(N −2) .
This is in contrast with their corresponding known solutions
in Einstein-Maxwell theory in both GR and TEGR. Also it is
important to mention that, in spite that the charged rotating
black hole has different components for gtt and grr , their
Killing and event horizons coincide.
To understand these solutions more, we calculate their
total energy and angular momentum. For this aim we have
used the mass/energy expression in the framework of f (T )
obtained by [4]. For the angular momentum we have used
the expression in [5]. We have used the form of the energymomentum tensor to calculate the total energy of the rotating
charged black holes and have shown that the resulting form
depends on the mass of the black hole which is consistent
with the derived form in [3].
For calculating the angular momentum of the solutions
one notices that, although there is a hamiltonian formulation for TEGR, which produces a known expression for the
angular momentum, there is no known expression for angular
momentum in f (T ) gravity. We argue that since the angular
Eur. Phys. J. C (2019) 79:668
momentum in our solution is independent of the charge q,
by sending q → 0 we obtain a solution with constant torsion scaler T , therefore, one can use the angular momentum
expression for TEGR following [5]. As a results we have used
the expressions obtained in [4] and [5] to calculate the mass
and angular momentum of these solutions together with the
subtraction technique used for asymptotically de-Sitter and
Anti-de-Sitter solutions. One of the interesting features that
we would like to check in future works is that if these milder
curvature singularities are weak enough to make these singularities “Tipler weak” according to Tipler’s criteria [46].
If it is weak enough, this might leads to possible extensions of the manifold as was shown in the same theory (i.e.,
f (T ) = T + αT 2 ) for some cosmological solutions in [47].
Acknowledgements This work is partially supported by the Egyptian
Ministry of Scientific Research under project No. 24-2-12.
Data Availability Statement This manuscript has no associated data
or the data will not be deposited. [Authors’ comment: No observational
datasets have been used.]
Open Access This article is distributed under the terms of the Creative
Commons Attribution 4.0 International License (http://creativecomm
ons.org/licenses/by/4.0/), which permits unrestricted use, distribution,
and reproduction in any medium, provided you give appropriate credit
to the original author(s) and the source, provide a link to the Creative
Commons license, and indicate if changes were made.
Funded by SCOAP3 .
References
1. J.P.S. Lemos, Cylindrical black hole in general relativity. Phys.
Lett. B 353, 46–51 (1995). arXiv:gr-qc/9404041
2. A.M. Awad, Higher dimensional charged rotating solutions in
(A)dS space-times. Class. Quantum Gravity 20, 2827–2834 (2003).
arXiv:hep-th/0209238
3. A.M. Awad, S. Capozziello, G.G.L. Nashed, D-dimensional
charged Anti-de-Sitter black holes in f (T ) gravity. JHEP 07, 136
(2017). arXiv:1706.01773
4. S.C. Ulhoa, E.P. Spaniol, On the gravitational energy-momentum
vector in f(T) Theories. Int. J. Mod. Phys. D 22, 1350069 (2013).
arXiv:1303.3144
5. J.W. Maluf, S.C. Ulhoa, On the gravitational angular momentum of rotating sources. Gen. Rel. Grav. 41, 1233–1247 (2009).
arXiv:0810.1934
6. Supernova Search Team collaboration, A.G. Riess et al., Observational evidence from supernovae for an accelerating universe
and a cosmological constant. Astron. J. 116, 1009–1038 (1998).
arXiv:astro-ph/9805201
7. Supernova Cosmology Project collaboration, S. Perlmutter et al.,
Measurements of omega and lambda from 42 high redshift supernovae. Astrophys. J. 517, 565–586 (1999). arXiv:astro-ph/9812133
8. J.M. Maldacena, The Large N limit of superconformal field theories and supergravity. Int. J. Theor. Phys. 38, 1113–1133 (1999).
arXiv:hep-th/9711200
9. S.W. Hawking, C.J. Hunter, M. Taylor, Rotation and the
AdS/CFT correspondence. Phys. Rev. D 59, 064005 (1999).
arXiv:hep-th/9811056
Page 7 of 8 668
10. A. Chamblin, R. Emparan, C.V. Johnson, R.C. Myers, Holography, thermodynamics and fluctuations of charged AdS black holes.
Phys. Rev. D 60, 104026 (1999). arXiv:hep-th/9904197
11. G.G.L. Nashed, Stability of the vacuum nonsingular black hole.
Chaos Solitons Fractals 15, 841 (2003). arXiv:gr-qc/0301008
12. W. El Hanafy, G.G.L. Nashed, Exact teleparallel gravity of binary
black holes. Astrophys. Sp. Sci. 361, 68 (2016). arXiv:1507.07377
13. D. Klemm, V. Moretti, L. Vanzo, Rotating topological black holes.
Phys. Rev. D 57, 6127–6137 (1998). arXiv:gr-qc/9710123
14. L. Iorio, E.N. Saridakis, Solar system constraints on f(T) gravity.
Mon. Not. R. Astron. Soc. 427, 1555 (2012). arXiv:1203.5781
15. G.L.N. Gamal, Spherically symmetric solutions on a non-trivial
frame in f(T) theories of gravity. Chin. Phys. Lett. 29, 050402
(2012). arXiv:1111.0003
16. Y. Xie, X.-M. Deng, f (T ) gravity: effects on astronomical observation and solar system experiments and upper-bounds. Mon. Not.
R. Astron. Soc. 433, 3584–3589 (2013). arXiv:1312.4103
17. A.M. Awad, Higher dimensional Taub-NUTS and Taub-Bolts in
Einstein-Maxwell gravity. Class. Quantum Gravity 23, 2849–2860
(2006). arXiv:hep-th/0508235
18. A.M. Awad, C.V. Johnson, Holographic stress tensors for
Kerr–AdS black holes. Phys. Rev. D 61, 084025 (2000).
arXiv:hep-th/9910040
19. A.M. Awad, C.V. Johnson, Scale versus conformal invariance in
the AdS/CFT correspondence. Phys. Rev. D 62, 125010 (2000).
arXiv:hep-th/0006037
20. S. Nojiri, S.D. Odintsov, Unifying inflation with lambda CDM
epoch in modified f(R) gravity consistent with solar system tests.
Phys. Lett. B 657, 238–245 (2007). arXiv:0707.1941
21. K. Bamba, S. Nojiri, S.D. Odintsov, The Universe future in modified gravity theories: approaching the finite-time future singularity.
JCAP 0810, 045 (2008). arXiv:0807.2575
22. T. Harko, F.S.N. Lobo, S. Nojiri, S.D. Odintsov, f (R, T ) gravity.
Phys. Rev. D 84, 024020 (2011). arXiv:1104.2669
23. G. Cognola, E. Elizalde, S. Nojiri, S.D. Odintsov, S. Zerbini,
Dark energy in modified Gauss-Bonnet gravity: late-time acceleration and the hierarchy problem. Phys. Rev. D 73, 084007 (2006).
arXiv:hep-th/0601008
24. K. Bamba, C.-Q. Geng, Thermodynamics of cosmological horizons
in f (T ) gravity. JCAP 1111, 008 (2011). arXiv:1109.1694
25. K. Bamba, C.-Q. Geng, C.-C. Lee, L.-W. Luo, Equation of
state for dark energy in f (T ) gravity. JCAP 1101, 021 (2011).
arXiv:1011.0508
26. K. Bamba, R. Myrzakulov, S. Nojiri, S.D. Odintsov, Reconstruction of f (T ) gravity: rip cosmology, finite-time future singularities and thermodynamics. Phys. Rev. D 85, 104036 (2012).
arXiv:1202.4057
27. R. Myrzakulov, Accelerating universe from F(T) gravity. Eur. Phys.
J. C 71, 1752 (2011). arXiv:1006.1120
28. M. De Laurentis, M. Paolella, S. Capozziello, Cosmological
inflation in F(R, G ) gravity. Phys. Rev. D 91, 083531 (2015).
arXiv:1503.04659
29. G.R. Bengochea, R. Ferraro, Dark torsion as the cosmic speed-up.
Phys. Rev. D 79, 124019 (2009). arXiv:0812.1205
30. E.V. Linder, Einstein’s other gravity and the acceleration of the
Universe. Phys. Rev. D 81, 127301 (2010). arXiv:1005.3039
31. Y.-F. Cai, S. Capozziello, M. De Laurentis, E.N. Saridakis, f(T)
teleparallel gravity and cosmology. Rep. Prog. Phys. 79, 106901
(2016). arXiv:1511.07586
32. B. Li, T.P. Sotiriou, J.D. Barrow, Large-scale structure in f(T) gravity. Phys. Rev. D 83, 104017 (2011). arXiv:1103.2786
33. B. Li, T.P. Sotiriou, J.D. Barrow, f (T ) gravity and local Lorentz
invariance. Phys. Rev. D 83, 064035 (2011). arXiv:1010.1041
34. G.L. Nashed, FRW in quadratic form of f (T ) gravitational theories. Gen. Relativ. Gravit. 47, 75 (2015). arXiv:1506.08695
123
668 Page 8 of 8
35. G.G.L. Nashed, Spherically symmetric charged-dS solution
in f (T ) gravity theories. Phys. Rev. D 88, 104034 (2013).
arXiv:1311.3131
36. G.G.L. Nashed, W. El Hanafy, Analytic rotating black hole solutions in N -dimensional f (T ) gravity. Eur. Phys. J. 90, (2017).
arXiv:1612.05106
37. S. Capozziello, P.A. Gonzalez, E.N. Saridakis, Y. Vasquez, Exact
charged black-hole solutions in D-dimensional f (T ) gravity: torsion vs curvature analysis. JHEP 02, 039 (2013). arXiv:1210.1098
38. G.G.L. Nashed, A special exact spherically symmetric solution in
f(T) gravity theories. Gen. Relativ. Grav. 45, 1887–1899 (2013).
arXiv:1502.05219
39. J. Stachel, Globally stationary but locally static space-times: a gravitational analog of the Aharonov-Bohm effect. Phys. Rev. 26, 1281–
1290 (1982)
40. R. Weitzenbök, Invarianten theorie (Noordhoff, Gröningen, 1923)
41. G.G.L. Nashed, E.N. Saridakis, Rotating AdS black holes in
Maxwell- f (T ) gravity. Class. Quantum Gravity 36, 135005
(2019). arXiv:1811.03658
123
Eur. Phys. J. C (2019) 79:668
42. G.W. Gibbons, S.W. Hawking, Action integrals and partition functions in quantum gravity. Phys. Rev. D 15, 2752–2756 (1977)
43. G.W. Gibbons, M.J. Perry, Black Holes and thermal green’s functions. Proc. R. Soc. Lond. A 358, 467–494 (1978)
44. G.W. Gibbons, S.W. Hawking, M.J. Perry, Path integrals and the
indefiniteness of the gravitational action. Nucl. Phys. B 138, 141–
150 (1978)
45. G.G.L. Nashed, Energy and momentum of a spherically symmetric
dilaton frame as regularized by teleparallel gravity. Ann. Phys. 523,
450–458 (2011). arXiv:1105.0328
46. F.J. Tipler, Singularities in conformally flat spacetimes. Phys. Lett.
A 64, 8–10 (1977)
47. A. Awad, G. Nashed, Generalized teleparallel cosmology and initial
singularity crossing. JCAP 1702, 046 (2017). arXiv:1701.06899