2. LIV Corrections to the Temperature and Entropy of a Charged Rotating Accelerated Black Hole
A charged rotating accelerated black hole is described by the C-metric as [
10,
11,
12]
In this C-metric,
M represents the mass scale of the black hole,
A denotes the acceleration, and
K represents the conical deficit of the spacetime. The parameter
ℓ corresponds to the negative cosmological constant, given by
, and
represents the parameter responsible for the rescaling of
t. Equation (
1) contains
The non-zero components of the electromagnetic potential
generated by the charge
q of this black hole at the event horizon
are respectively:
Based on Equations (
1) and (
2), the corresponding determinant of the metric
can be calculated as:
From Equations (
1), (
2) and (
4), the contravariant metric tensor can be calculated as:
where,
Equation (
6) described non-zero components of
. The event horizon of this black hole is determined by the following null hypersurface equation.
Substituting Equation (
6) into Equation (
7) gives the equation that the event horizon
of this black hole satisfies:
From this equation, it is clear that the event horizon
of this black hole is related to
. The curved spacetime described by Equation (
1) possesses a Killing vector
. Since
is related to
, the two-dimensional line element
at the north pole (
) and the south pole (
) on the event horizon are not the same. This difference is what makes this accelerated black hole unique. To explain the acceleration mechanism of this black hole, it is necessary to clarify the cause of its accelerated motion. Physically speaking, the energy-momentum tensor of physical entities that can interact with the event horizon of this black hole satisfies the condition
in the local region. The physical entity that satisfies this condition is a cosmic string. The energy-momentum of the cosmic string is dominated by its mass per unit length, and the string’s tension is numerically equal to this energy [
13]. The gravitational effect of a cosmic string does not generate long-range curvature in spacetime but induces a global conical defect on the spatial section perpendicular to the string. Therefore, we can consider the cosmic string as essentially a localized conical deficit in spacetime. It is this conical deficit that drives the accelerated motion of this black hole. This is the fundamental reason for the accelerated motion of the black hole, with the acceleration parameter denoted by
A. From Equation (
2), it can be seen that
A affects
, and this effect manifests as an influence on the cosmological constant. The effect of
A on
primarily reflects the range of values for
. Therefore, we can impose the condition
, which better reflects the variation in
. According to Equations (
1) and (
2), the regularity of the metric at a pole requires that
be as follows:
If
is fixed with
along the two-pole axis, given by [
7,
9,
14]
The deficit angle of the conical defect is interpreted as being due to the cosmic string. We can consider the tensions of the strings along each axis as
, that is
Here, the + sign corresponds to the north pole, and the − sign corresponds to the south pole.
is interpreted as a cosmic string emerging from the black hole, causing it to accelerate. Knowing the reason for the accelerated motion of this black hole and the basic characteristics of the curved spacetime, we can study the thermodynamic evolution of this charged, rotating, accelerated black hole.
In the spacetime of this charged, rotating, accelerated black hole, the equation for spin-
fermions is the Dirac equation, which is given by:
where,
where
is the spin connection in the curved spacetime. It is given by
. In the spacetime of the charged, rotating, accelerated black hole described by Equations (
1) and (
2), and considering LIV corrections, we propose modifying Equation (
12) as [
15]:
The term
in Equation (
14) represents the LIV correction written according to the contraction rules for differential and tensor free indices in general relativity. The coupling constant
. In fact, Keuglov considered LIV corrections in flat spacetime and introduced a correction term
, which modified the Dirac equation [
15]. When extending this to curved spacetime, the LIV correction term we choose must be as shown in Equation (
14).
in Equation (
14) is the mass of the Dirac particle.
is the wave function of the spin-
fermions.
is the gamma matrix in the curved spacetime described by Equation (
1). The
matrices are required to satisfy the following commutation relation:
The
matrices that satisfy Equations (
1) and (
15) are given as follows:
The Pauli matrices
are expressed as follows:
According to the WKB semiclassical approximation theory, we can express the wave function
in Equation (
14) in terms of the particle action
S as follows:
Substituting Equation (
18) into Equation (
14), we can obtain:
In Equation (
19),
is a 4 × 4 matrix, and
A and
B must be 2-dimensional spinors. In the above equation,
is a Hermitian matrix. The solution of the matrix equation can only be guaranteed to have physical significance if the matrix is Hermitian. In Equation (
19), there is a term that contains the imaginary unit
i, and another term related to
. In order to solve for the particle action
S, we need to correctly choose a transformation related to
and
based on the characteristics of the stationary spacetime. Therefore, we need to introduce a matrix transformation based on the characteristics of the stationary, axisymmetric black hole spacetime as follows:
From this, it can be concluded that:
Substituting Equation (
22) into Equation (
19), we obtain the spin-
fermion equation in the spacetime of the charged, rotating, accelerated black hole as:
This is a matrix equation, and in fact, it is an eigenmatrix equation. The
in Equation (
23) is related to
. From this equation, we see that the
is a 4 × 1 matrix and both A and B are 2-component spinors. The wave function
represented by the semiclassical WKB approximation theory is meaningful. The four terms inside the left-hand bracket of Equation (
23) that are independent of
are all related to scalars. In the matrix equation Equation (
23),
can actually be expressed as
, where
is a 2 × 2 identity matrix, and the other three terms can be expressed in a similar way. The first term inside the left-hand bracket of the equation no longer has free indices because the upper index
and the lower index
have already been contracted. Therefore, this term can also be expressed as a term involving a 4 × 4 identity matrix. We denote the term inside the left-hand bracket of Equation (
23) as
G, we have
That is
This matrix equation is an eigenmatrix equation. For this equation to have a non-trivial solution, we must require that the determinant of the matrix
is zero, that is,
From this equation, it can be concluded that
So, we obtain the following equation:
The first term on the left-hand side of Equation (
28) contains the imaginary unit
i. To solve this equation, we use the relationship between
and
, as shown in Equation (
20). By multiplying both sides of Equation (
28) by
and utilizing the relation between
and
given in Equation (
15), we obtain:
From Equation (
28) to Equation (
29),
is neglected, and we set
,
, where
is the correction parameter. It should be noted that in Equations (
19), (
23), (
28) and (
29), the free indices
and
take values 0, 1, 2, 3. When the upper index
(or
) is contracted with the lower index
(or
), it results in a scalar term (with no free indices). Therefore, each term on the left-hand side of Equations (
19), (
23), (
28) and (
29) is a scalar. Equation (
29) is the semiclassical modified form of the dynamical equation for spin-
fermions in the spacetime of a charged, rotating, accelerated black hole, expressed in terms of the particle action, including LIV corrections. The equation without the LIV correction term is the Hamilton-Jacobi equation. Therefore, Equation (
29) is an equation that can be used to study the characteristics of stationary black hole quantum tunneling radiation. Substituting Equation (
6) into Equation (
29) gives:
In the curved spacetime described by Equations (
1) and (
2), with the basic characteristics of a stationary spacetime and a Killing vector
, the particle action
S in Equation (
30) can be separated into the following form:
Substituting Equation (
31) into Equation (
30) and performing variable separation, let the constant introduced during the separation process be denoted as
. We can then obtain the equation satisfied by the radial action
for the spin-
fermion in the curved spacetime described by Equation (
1) as:
As
, we have
. Therefore, from Equation (
32), we obtain:
where,
By applying the residue theorem and integrating both sides of Equation (
33), we obtain the radial action
as:
where,
According to the theory of black hole quantum tunneling radiation, the quantum tunneling rate for spin-
fermions at the event horizon
of this charged, rotating, accelerated black hole is given by [
16,
17]:
where
is the Hawking temperature of the event horizon of this black hole, given by:
where the higher-order small quantity
is neglected. Obviously, LIV has an impact on
.
is independent of
. According to the zeroth law of black hole thermodynamics, the surface gravity
of a stationary black hole is a constant, and
, where
is constant. According to the first law of black hole thermodynamics, there is an inherent connection between the black hole temperature and entropy. The first law of thermodynamics for accelerated black holes with conical deficits has been studied in [
7,
8,
18,
19,
20]. Reference [
21] investigates the modified Bekenstein–Hawking entropy for a charged, non-rotating accelerated black hole. In contrast to these studies, this paper focuses on the modified Bekenstein–Hawking entropy for charged, rotating, accelerated black holes and its associated physical significance. We denote the tensions of the strings along each axis as
and the thermodynamic length associated with the string tensions as
, and use
to represent the Bekenstein–Hawking entropy of this black hole. Include the conical deficit as a change and introduce the conjugate chemical potential, use tools from holographic renormalization to properly calculate the various charges of the slowly accelerating black hole spacetime the mathematical expression for the first law of thermodynamics related to this black hole is as follows [
8,
18]:
In Equation (
39), the mass of the black hole is determined as
. The accelerating black hole also obeys a Smarr relation
. The value of
, satisfying the first law and the Smarr relation, is given by
[
8,
10,
18]. Where
V is the thermodynamic volume of this black hole.
,
. From Equation (
39), it follows that
where
is the Bekenstein–Hawking entropy of this black hole without LIV corrections. To calculate
, we first consider the 2-dimensional line element obtained from Equation (
1) as follows:
From Equation (
41), the area of the event horizon of this black hole is given by:
Therefore,
. The entropy
in Equation (
40) can be expressed as:
Here, the higher-order small quantity
is neglected. Where
K is as shown in Equation (
9). From Equation (
43), it can be seen that LIV introduces a correction to the entropy of this black hole.
In addition to the LIV corrections, we can also consider the effects of quantum corrections. For this, let
, and use
ℏ perturbation theory to express the energy and radial action of the spin-
fermion as follows:
Here,
represents the radial action in semiclassical theory, as shown in Equation (
35).
corresponds to
in Equations (
33), (
35) and (
37). From Equation (
45), we have
. Using Equations (
33), (
44) and (
45), we can obtain the equation associated with
as follows:
Similarly, one can write down the equation satisfied by
. Obviously, there exists a definite relationship between
and
. Let
, from Equations (
35) and (
45)–(
48), we obtain:
From this, we can derive the quantum tunneling rate for the spin-
fermion at the event horizon of this black hole as:
where,
After the
corrections, the Bekenstein–Hawking entropy can be expressed as:
where
. In
, the LIV correction term is represented by the coefficient
, while in
, the correction terms include both the LIV correction coefficient and the
correction terms. Equation (
52) represents the new expression for the modified Bekenstein–Hawking entropy of the charged, rotating, accelerated black hole, as described by Equations (
1) and (
2).
It should be further clarified that, according to the literature [
15], the Dirac equation for spin-1/2 particles in flat spacetime with LIV corrections is given by
, where
, and
. When considering
, we obtain
. When
, the well-known Lorentz dispersion relation is recovered. Both general relativity and quantum field theory are based on the Lorentz dispersion relation. The study of LIV has prompted research into modified forms of the fermion dynamics equations in both flat and curved spacetime, as well as related topics. The above research method is not suitable for studying the dynamics equations of bosons. In the next section, we will investigate the modifications to the boson dynamics equations in curved spacetime as described by Equations (
1)–(
3), along with the related topics.
3. Lorentz-Breaking and the Scalar Field Equation and Black Hole Entropy in the Spacetime of a Charged Rotating Accelerating Black Hole
The previous section discussed the LIV corrections to the dynamical equations of spinor field particles, and used the spin-
fermion as an example to study the modified entropy of a charged, rotating, accelerating black hole. Since the effects of LIV can be studied in curved spacetime, we can more generally express Lorentz violation as Lorentz-breaking. This allows us to introduce Lorentz-breaking correction terms into the particle action in different gravitational fields, and, based on this, apply the variational principle to obtain the modified particle dynamics equations. The following section will use a scalar particle with zero spin as an example to study the modification of the entropy of the charged, rotating, accelerating black hole. LIV indicates that Lorentz symmetry is broken under high-energy conditions. The Einstein-aether theory is a gravitational theory that incorporates Lorentz-breaking. By introducing an aether-like vector field
, the action of Einstein’s gravitational field is modified. Then, using the variational principle, the modified form of the scalar field equation is derived. Based on this, the modified dynamical equation for scalar particles (bosons) with spin zero is obtained using the WKB approximation theory, as follows [
21].
This is a semiclassical dynamical equation for spin-0 Bosons. The correction term
corresponds to the Lorentz-breaking correction term in the Einstein-aether gravity theory. For Bosons with other spins, a separate study is required to investigate the modified form of their dynamical equations. In Equation (
14),
is a coupling constant and
. The reference [
21] uses this equation to study the quantum tunneling radiation characteristics of a class of black holes, but the quantum tunneling radiation features in curved spacetime described by Equations (
1)–(
3) have not been studied yet. According to Equations (
1) and (
2), the chosen
must satisfy the condition
. The four components of
are selected as follows:
From this equation, we can see that
(constant). Therefore, the chosen
is correct. By substituting Equations (
6) and (
54) into Equation (
53), the dynamical equation for the spin-zero boson in the spacetime of the charged, rotating, accelerating black hole is given by:
Separate the variables in this equation. Isolate the equation involving
, let
is the constant introduced during the separation process. Consider that both
and
are related to
, and that
. Therefore, we examine the case where
. Substituting Equation (
31) into Equation (
55), we obtain
From this equation, we obtain:
where
is consistent with Equation (
33). Applying the residue theorem to solve Equation (
57), we obtain:
where
is as shown in Equation (
36). According to the quantum tunneling radiation theory for black holes, we obtain the quantum tunneling rate for the spin-zero boson at the event horizon of the charged, rotating, accelerating black hole as:
where,
Here, higher-order small quantities
are neglected. This is the result of introducing the aether-like vector field
according to the Einstein-aether gravitational theory and the correction to the Hawking temperature and quantum tunneling rate of this black hole. Clearly, the components
and
of
have an influence on the tunneling radiation of this black hole. Once the Lorentz-breaking effects are taken into account, the quantum tunneling radiation of this black hole will be significantly affected by the LIV corrections. Based on the corresponding expression of the first law of thermodynamics for this black hole (Equation (
39)), we can obtain the corrected Bekenstein–Hawking entropy of this black hole under the Einstein-aether theory as
According Equation (
42)
. The corrections to this black hole are related to
. The above results regarding the tunneling radiation of spin-zero bosons are derived within the semiclassical theory. To further investigate the quantum corrections, the perturbative theory involving
ℏ needs to be considered for further refinement. Using the same
ℏ-expansion method as in the previous section, we can derive the corrected result for the entropy of this black hole, which is logarithmically related, i.e.,
The
in Equation (
61) is related to the
in Equation (
52), as shown in Equation (
43).