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References - Bogoliubov Laboratory of Theoretical Physics - JINR

References - Bogoliubov Laboratory of Theoretical Physics - JINR

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Schwinger gauge. Probably for the first time introduced independently by Schwinger<br />

[5] and Dirac [6] (and widely used in many works, including [7] and our current study),<br />

this choice demands that the tetrad matrix e α i and its inverse ei α satisfy e�0 b =0,e 0 � b =0.<br />

Landau-Lifshitz gauge (see, e.g., Ref. [8]) fixes the tetrad so that e �a 0 =0,ea �0 =0.<br />

Symmetric gauge. Using the Minkowski flat metric gαβ =diag(c 2 , −1, −1, −1), we<br />

. Now assume that the<br />

can move the anholonomic index down and define eαi := gαβe β<br />

i<br />

resulting matrix is invariant under the transposition operation that can be symbolically<br />

written as eαi = eiα. Such a tetrad was used by Pomeransky and Khriplovich [9] and<br />

Dvornikov [10].<br />

We choose the Schwinger gauge by specifying the c<strong>of</strong>rame as (5). The other tetrads<br />

are obtained from our e α i with the help <strong>of</strong> the Lorentz transformation e′α i =Λα βe β<br />

i ,where<br />

Λ α β =<br />

� λ λqb/c<br />

λcq a<br />

δ a b +(λ − 1)qa qb/q 2<br />

�<br />

, q a = ξ WKa<br />

, λ =<br />

V<br />

1<br />

� . (10)<br />

1 − q2 The constant ξ conveniently parametrizes different choices <strong>of</strong> tetrads. Namely, for ξ =1/2<br />

the Lorentz matrix (10) transforms our tetrad to that <strong>of</strong> Pomeransky and Khriplovich,<br />

and for ξ = 1 we obtain the tetrad <strong>of</strong> Landau and Lifshitz.<br />

The spin precession in the gravitational field <strong>of</strong> rotating object is given by<br />

where we denote<br />

ρ =<br />

2γ +1<br />

γ +1<br />

GM γ<br />

r +<br />

r3 γ +1<br />

Ω = G<br />

c 2 r 3<br />

�<br />

3r(r · J)<br />

r2 �<br />

− J + ρ × v<br />

c2 , (11)<br />

3G<br />

c2r3 �<br />

r<br />

2ξ<br />

· v)<br />

(r · (J × v)) − J × v +(2ξ− 1)(r<br />

r2 3 r2 �<br />

J × r .<br />

(12)<br />

Putting ξ = 0, thus specifying to the Schwinger tetrad, we find that the classical formula<br />

(11) perfectly reproduces the quantum result (9). If we choose another tetrad by putting<br />

ξ =1/2 in (12), the equation (11) yields the result by Pomeransky and Khriplovich [9]<br />

and Dvornikov [10] which differs from Eq. (9).<br />

For particles in a rotating frame, the angular velocity <strong>of</strong> spin precession is given by<br />

Ω = −ω + ξγ v × (v × ω)<br />

γ +1 c2 . (13)<br />

The correct result for the Schwinger gauge (ξ = 0) was first obtained in [11]. An<br />

explanation <strong>of</strong> the dependence <strong>of</strong> the angular velocity <strong>of</strong> the spin precession on the gauge<br />

<strong>of</strong> a tetrad was presented recently [12] on the basis <strong>of</strong> the Thomas precession.<br />

The Lense-Thirring effect or frame dragging is one <strong>of</strong> the most impressive predictions<br />

<strong>of</strong> the general relativity. This effect is currently analyzed in the Gravity Probe B experiment<br />

[13]. However, relativistic corrections to the LT effect are not observable in this<br />

experiment as well as in other experiments inside the solar system [14]. Nevertheless,<br />

it is necessary to take the relativistic corrections to the LT precession into account for<br />

the investigation <strong>of</strong> physical phenomena in the binary stars such as pulsar systems. In<br />

this case, both components <strong>of</strong> a system undergo a mutual LT precession about the total<br />

angular momentum J. Since the spin precession effects are well observable [15], the use <strong>of</strong><br />

457

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