Abstract
The results of a study of the Dirac Hamiltonian for a point electron in the zero-gravity Kerr–Newman spacetime are reported; here, “zero-gravity” means G → 0, where G is Newton’s constant of universal gravitation, and the limit is effected in the Boyer–Lindquist coordinate chart of the maximal analytically extended, topologically nontrivial, Kerr–Newman spacetime. In a nutshell, the results are: the essential self-adjointness of the Dirac Hamiltonian; the reflection symmetry about zero of its spectrum; the location of the essential spectrum, exhibiting a gap about zero; and (under two smallness assumptions on some parameters) the existence of a point spectrum in this gap, corresponding to bound states of Dirac’s point electron in the electromagnetic field of the zero-G Kerr–Newman ring singularity. The symmetry result of the spectrum extends to the Dirac Hamiltonian for a point electron in a generalization of the zero-G Kerr–Newman spacetime with different ratio of electric-monopole to magnetic-dipole moment. The results are discussed in the context of the general-relativistic hydrogen problem. Also, some interesting projects for further inquiry are listed in the lastsection.
Mathematics Subject Classification (2010). 81, 83, 35.
This is an expanded version of the talk titled “The Dirac equation and the Kerr-Newman spacetime,” given by the first author at the Quantum Mathematical Physics conference.
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Notes
- 1.
We are not suggesting that experimental physicists should not worry about this academic problem. For the empirically relevant problem to estimate the influence of, say, Earth’s gravitational field on the spectrum of hydrogen in the lab, see Papapetrou [40].
- 2.
We follow the notation of Lieb and Loss [34]; thus \(C_{c}^{\infty }(\mathbb{R}^{3}\setminus \{\boldsymbol{0}\})\) denotes functions which are compactly supported away from the origin in \(\mathbb{R}^{3}\).
- 3.
For a modern semi-classical approach that produces these quantum numbers, see [30].
- 4.
The additive constant mc 2 drops out in the calculation of Rydberg’s empirical formula for the frequencies of the emitted/absorbed radiation, which are proportional to the differences of the discrete energy eigenvalues.
- 5.
This well-known naked singularity is usually not considered to be a counterexample of the (weak) cosmic censorship hypothesis, based on the following reasoning: paraphrasing Freeman Dyson, general relativity is a classical physical theory which applies only to physics in the large (e.g. astrophysical and cosmic scales), not to atomic physics; and so, since cosmic bodies of mass m and charge q must have a ratio G m 2∕q 2 ≫ 1, the Reissner–Nordström spacetime of such a body (assumed spherical), when collapsed, exhibits a black hole, not a naked singularity. While we agree that cosmic bodies (in mechanical virial-equilibrium) must have a ratio G m 2∕q 2 ≫ 1, we don’t see why the successful applications of general relativity theory at astrophysical and cosmic scales would imply that general relativity cannot be successfully applied at atomic, or even sub-atomic scales, where typically G m 2∕e 2 ≪ 1.
- 6.
Interestingly enough, though, Belgiorno–Martellini–Baldicchi [8] proved the existence of bound states of a Dirac point electron equipped with an anomalous magnetic moment in the Reissner–Nordström spacetime with naked singularity, provided the anomalous magnetic moment is large enough; in that case, the Dirac Hamiltonian is essentially self-adjoint.
- 7.
The addition of a positive cosmological constant [6] has not lead to bound states either.
- 8.
For integrable yet infinitely extended astrophysical Kerr–Newman disc sources, see [33].
References
P. Appell, Quelques remarques sur la théorie des potentiels multiforms. Math. Ann. 30, 155–156 (1887)
D. Batic, H. Schmid, The Dirac propagator in the Kerr–Newman metric. Prog. Theor. Phys. 116, 517–544 (2006)
D. Batic, H. Schmid, Chandrasekhar Ansatz and the generalized total angular momentum operator for the Dirac equation in the Kerr–Newman metric. Rev. Colomb. Mat. 42, 183–207 (2008)
D. Batic, H. Schmid, M. Winklmeier, On the eigenvalues of the Chandrasekhar-Page angular equation. J. Math. Phys. 46, 012504 (35) (2005)
F. Belgiorno, Massive Dirac fields in naked and in black hole Reissner–Nordström manifolds. Phys. Rev. D 58, 084017 (8) (1998)
F. Belgiorno, S.L. Cacciatori, The Dirac equation in Kerr–Newman–AdS black hole background. J. Math. Phys. 51, 033517 (32) (2010)
F. Belgiorno, M. Martellini, Quantum properties of the electron field in Kerr-Newman black hole manifolds. Phys. Lett. B 453, 17–22 (1999)
F. Belgiorno, M. Martellini, M. Baldicchi, Naked Reissner-Nordström singularities and the anomalous magnetic moment of the electron field. Phys. Rev. D 62, 084014 (2000)
H.A. Bethe, E.E. Salpeter, Quantum Mechanics of One- and Two-Electron Atoms (Plenum Press, New York, 1977)
D.R. Brill, J.M. Cohen, Cartan frames and the general relativistic Dirac equation. J. Math. Phys. 7, 238–243 (1966)
B. Carter, Global structure of the Kerr family of gravitational fields. Phys. Rev. 174, 1559–1571 (1968)
A. Cáceres, C. Doran, Minimax determination of the energy spectrum of the Dirac equation in a Schwarzschild background. Phys. Rev. A 72, 022103 (7) (2005)
B. Carter, R.G. McLenaghan, Generalized master equations for wave equation separation in a Kerr or Kerr-Newman black hole background, in Proceedings of the 2nd Marcel Grossmann meeting on general relativity, ed. by R. Ruffini (North-Holland, Amsterdam, 1982), pp. 575–585
S. Chandrasekhar, The solution of Dirac’s equation in Kerr geometry. Proc. R. Soc. Lond. Ser. A 349, 571–575 (1976)
S. Chandrasekhar, Errata: the solution of Dirac’s equation in Kerr geometry. Proc. R. Soc. Lond. Ser. A 350, 565 (1976)
J.M. Cohen, R.T. Powers, The general relativistic hydrogen atom. Commun. Math. Phys. 86, 69–86 (1982)
G.C. Evans, Lectures on Multiple-Valued Harmonic Functions in Space (University of California Press, Berkeley/Los Angeles, 1951)
R.P. Feynman, Theory of positrons. Phys. Rev. 76, 749–759 (1949)
F. Finster, J. Smoller, S.-T. Yau, Nonexistence of time-periodic solutions of the Dirac equation in Reissner–Nordström black hole background. J. Math. Phys. 41, 2173–2194 (2000)
F. Finster, N. Kamran, J. Smoller, S.-T. Yau, Nonexistence of time-periodic solutions of the Dirac equation in an axisymmetric black hole geometry. Commun. Pure Appl. Math. 53, 902–929 (2000)
F. Finster, N. Kamran, J. Smoller, S.-T. Yau, Erratum: nonexistence of time-periodic solutions of the Dirac equation in an axisymmetric black hole geometry. Commun. Pure Appl. Math. 53, 1201 (2000)
F. Finster, N. Kamran, J. Smoller, S.-T. Yau, Decay rates and probability estimates for massive Dirac particles in the Kerr–Newman black hole geometry. Commun. Math. Phys. 230, 201–244 (2002)
F. Finster, N. Kamran, J. Smoller, S.-T. Yau, The long-time dynamics of Dirac particles in the Kerr–Newman black hole geometry. Adv. Theor. Math. Phys. 7, 25–52 (2003)
J. Gair, An Investigation of Bound States in the Kerr–Newman Potential. Prize Essay (Cambridge University, 2001)
R. Geroch, Limits of spacetimes. Commun. Math. Phys. 13, 180–193 (1969)
W. Greiner, B. Müller, J. Rafelski, Quantum Electrodynamics of Strong Fields (Springer, Berlin/New York, 1985)
C. Heinecke, F.W. Hehl, Schwarzschild and Kerr solutions to Einstein’s field equations: an introduction. Int. J. Mod. Phys. D (2015, in press)
W. Israel, Source of the Kerr metric. Phys. Rev. D 2, 641–646 (1970)
G. Kaiser, Distributional sources for Newman’s holomorphic Coulomb field. J. Phys. A 37, 8735–8745 (2004)
S. Keppeler, Spinning Particles—Semiclassics and Spectral Statistics (Springer, Berlin, 2003)
M.K.-H. Kiessling, A.S. Tahvildar-Zadeh, A novel quantum-mechanical interpretation of the Dirac equation. eprint arXiv:1411.2296 (2014)
M.K.-H. Kiessling, A.S. Tahvildar-Zadeh, The Dirac point electron in zero-gravity Kerr–Newman spacetime. J. Math. Phys. 56, 042303 (43) (2015)
T. Ledvinka, M. Žofka, J. Bičák, Relativistic disks as sources of Kerr–Newman fields, in Proceedings of the 8th Marcel Grossmann meeting on general relativity, Jerusalem (1997), ed. by R. Ruffini (World Scientific, Singapore, 1998)
E.H. Lieb, M. Loss, Analysis, 2nd edn. (American Mathematical Society, Providence, 2010)
D. Lynden-Bell, Electromagnetic magic: the relativistically rotating disk. Phys. Rev. D 70, 105017 (10) (2004)
G.C. McVittie, Dirac’s equation in general relativity. Mon. Not. R. Astron. Soc. 92, 868–877 (1932)
F. Melnyk, Wave operators for the massive charged linear Dirac field on the Reissner–Nordström metric. Class. Quantum Gravity 17, 2281–2296 (2000)
E.T. Newman, E. Couch, K. Chinnapared, A. Exton, A. Prakash, R. Torrence, Metric of a rotating, charged mass. J. Math. Phys. 6, 918–919 (1965)
D. Page, Dirac equation around a charged, rotating black hole. Phys. Rev. D 14, 1509–1510 (1976)
A. Papapetrou, Rotverschiebung und Bewegungsgleichungen. Ann. Phys. 452, 214–224 (1956)
C.L. Pekeris, The nucleus as a source in Kerr–Newman geometry. Phys. Rev. A 35, 14–17 (1987)
E. Schrödinger, Diracsches Elektron im Schwerefeld. I. Sitzber. Preuss. Akad. Wiss. 11–12, 105–128 (1932)
A. Sommerfeld, Über verzweigte Potentiale im Raum. Proc. Lond. Math. Soc. s1-28, 395–429 (1896)
E.C.G. Stückelberg, La mécanique du point matériel en théorie de relativité et en théorie des quanta. Helv. Phys. Acta 15, 23–37 (1942)
K.G. Suffern, E.D. Fackerell, C.M. Cosgrove, Eigenvalues of the Chandrasekhar–Page angular functions. J. Math. Phys. 24, 1350–1358 (1983)
A.S. Tahvildar-Zadeh, On the static spacetime of a single point charge. Rev. Math. Phys. 23, 309–346 (2011)
A.S. Tahvildar-Zadeh, On a zero-gravity limit of the Kerr–Newman spacetime and its electromagnetic fields. J. Math. Phys. 56, 042501 (19pp) (2015)
B. Thaller, Potential scattering of Dirac particles. J. Phys. A: Math. Gen. 14, 3067–3083 (1981)
B. Thaller, The Dirac Equation (Springer, Berlin, 1992)
J. Weidmann, Absolut stetiges Spektrum bei Sturm-Liouville-Operatoren und Dirac-Systemen. Math. Z. 180, 423–427 (1982)
M. Winklmeier, O. Yamada, Spectral analysis of radial Dirac operators in the Kerr-Newman metric and its applications to time-periodic solutions. J. Math. Phys. 47, 102503 (17) (2006)
M. Winklmeier, O. Yamada, A spectral approach to the Dirac equation in the non-extreme Kerr–Newman metric. J. Phys. A 42, 295204 (15) (2009)
A. Zecca, Dirac equation in Schwarzschild geometry. Nuovo Cim. B 113, 1309–1315 (1998)
D.M. Zipoy, Topology of some spheroidal metrics. J. Math. Phys. 7, 1137–1143 (1966)
Acknowledgements
Many thanks go to Felix Finster, Jürgen Tolksdorf, and Eberhard Zeidler for their kind invitation to present these results at their superbly organized conference, and for the financial support and the impeccable hospitality offered by the organizers and their staff. We also thank Donald Lynden-Bell and Jonathan Gair for the permission to reproduce their field line drawings (Fig. 1). Finally, we thank the referee for a very careful reading of our paper, and for constructive criticisms.
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Kiessling, M.KH., Tahvildar-Zadeh, A.S. (2016). Dirac’s Point Electron in the Zero-Gravity Kerr–Newman World. In: Finster, F., Kleiner, J., Röken, C., Tolksdorf, J. (eds) Quantum Mathematical Physics. Birkhäuser, Cham. https://doi.org/10.1007/978-3-319-26902-3_19
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