In four dimensions, the Minkowski metric leads to the 16-dimensional Clifford algebra C(1,3), Dirac's equation [1] is using four of these 16 matrices that form a basis of this algebra, a new operator is defined using all of these matrices and also generalized for a curved space. This new multilevel operator generalizes the Dirac's equation, the value of the generalized Dirac's operator is calculated in the Schwarzschild's metric. The torsion tensor is calculated taking into account the non-symmetric part of the metric tensor in the vanishing of its covariant derivative and applied to Kerr's metric generalizing the Clifford algebra.

*Gravitomagnetic Tensor; Gravitational Magnetic Field; Energymomentum1-Form; Clifford Algebra; Dirac Equation; Dirac Operator; Gravity and Quantum Mechanics Unification; Multilevel Operator; Schwarzschild's Metric; Torsion Tensor; Rearranged Kerr's Metric; Generalized Clifford Algebra*

Dirac's equation is the relativistic wave equation derived by physicist Paul Dirac in 1928. The wave functions in the Dirac theory are vectors of four complex components (known as bispinors), two of which resemble the Pauli wavefunction in the non-relativistic limit, in contrast to the Schrodinger equation which described wave functions of only one complex component [1, 2].

Dirac's operator is just the tip of the iceberg, the tip of a generalized operator that is obtained by operating on all members of the Clifford algebra basis and not just on four of them.

The Schwarzschild's metric is named in honour of Karl Schwarzschild, who found the exact solution in 1915 and published it in January 1916, a little more than a month after the publication of Einstein's theory of general relativity. It was the first exact solution of the Einstein field equations other than the trivial at space solution. Schwarzschild died shortly after his paper was published, as a result of a disease he developed while serving in the German army during World War I. Johannes Droste in 1916 independently produced the same solution as Schwarzschild.

Schwarzschild's metric is an exact solution to the Einstein's field equations that describes the gravitational field outside a spherical mass, on the assumption that the electric charge of the mass, angular momentum of the mass, and universal cosmological constant is all zero.

The new generalized Dirac's operator, the multilevel operator, is calculated in the Schwarzschild's metric, torsion tensor and new gravitomagnetic tensor appear in level 2, curvature tensor appears in levels 3 and 4.

The Kerr's metric is a generalization to a rotating body of the Schwarzschild's metric.

## Multilevel operator

We are using Pauli matrices σ, electromagnetic four-potential and charge e with

1

In four dimensions, Minkowski's metric *η*_{μν} = diag (+1,-1,-1,-1) leads to the Clifford algebra C(1,3)[2], Dirac matrices

2

Multilevel operator *D*^{n} acts on level n, n is the number of matrices in the product of the algebra members, for example, *D*^{3} acts on *γ*^{10}, γ^{11}, γ^{12}, and *γ*^{13}. Total multilevel operator = D^{0} +D^{1} +D^{2} +D^{3} +D^{4}, the action of on the spinor function vanishes ψ=0 3

4

5

6

7

8

9

Multilevel operator can be generalized for a curved space with four-potential P, field charge q and covariant derivative [3] instead of derivative in the definition of

10

11

12

13

with 14

15

16

17

For gravity is the new gravitomagnetic tensor. is the torsion tensor [4].

18

with the Riemann-Christoffel tensor [5]. 19

20

21

22

23

We are using with , this metric is defined by [6]

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

, from equations (16) and (17) 40

41

42

43

44

45

46

47

Energy-momentum form is a 1-form [7]

48

**dp** is a 2-form

49

50

51

52

Comparing equations (41-43) and (50-52) we can infer

53

is related to the scalar 0 -form is related to the Energy-momentum 1-form, is related to the Electromagnetic 2 -form, is related to

3-form [8].

54

is related to **L** 4-form [9].

55

is the proyector matrix, historically

56

## Torsion Tensor in a Rearranged Kerr's Metric

We are using M is the black hole's mass and a is the angular momentum per unit mass with G = c = 1. The invariance of the length of vectors under parallel transport means that the connection is compatible with the metric, it is a metric connection, the requirement of the preservation of the length by parallel transport may be stated as [10].

57

58

, with 59

60

61

62

Solving these equations, we get the torsion applying its definition [11].

63

Expanding the line element in powers of and examining the leading terms [12].

64

Rearranging the line elements

65

66

67

68

69

70

71

72

73

74

75

76

77

78

Generalizing Clifford algebra with , if and then 1, else 0

79

80

81

82

83

, from equations (16) and (17) 84

85

86

87

88

89

90

is the proyector matrix, historically , but

91

Multilevel operator has been generalized for a curved space with a general four-potential P. For gravity is the new gravitomagnetic tensor and torsion tensor appears in its definition.

In a at space and operators vanish. In a curved space the curvature tensor appears in levels 3 and 4.

The appearance of torsion tensor and curvature tensor in multilevel operator means that this operator is a fundamental operator in Quantum Field Theory.

, have been calculated for Schwarzschild's metric, then , the gravitomagnetic tensor has been obtained

Each, where n is the number of γ matrices in the product of the algebra members, is related to an n-form.

The invariance of the length of vectors under parallel transport requires the vanishing of the metric tensor covariant derivative, a new term appears in equation (59) with measuring the non-symmetric part of the metric tensor, solving these equations we get the torsion tensor.

Rearranging Kerr's metric we obtained , the non-symmetric part of the metric tensor, gravitomagnetic tensor has also been calculated generalizing the Clifford algebra.

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