In a recent paper it is claimed that vacuum birefringence has been experimentally observed for the first time by measuring the degree of polarization of visible light from a magnetar candidate, a neutron star with a magnetic field presumably as large as 10^13 G. The role of such a strong magnetic field is twofold. First, the surface of the star emits, at each point, polarized light with linear polarization correlated with the orientation of the magnetic field. Depending on the relative orientation of the magnetic axis of the star with the direction to the distant observer, a certain degree of polarization should be visible. Second, the strong magnetic field in the vacuum surrounding the star could enhance the effective degree of polarization observed: vacuum birefringence. We compare experimental data and theoretical expectations concluding that the conditions to support a claim of strong evidence of vacuum birefringence effects are not met.

A note on polarized light from magnetars / Capparelli, L. M.; Damiano, A.; Maiani, L.; Polosa, A. D.. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - ELETTRONICO. - 77:11(2017), p. 754. [10.1140/epjc/s10052-017-5342-3]

A note on polarized light from magnetars

Capparelli, L. M.;Damiano, A.;Maiani, L.;Polosa, A. D.
2017

Abstract

In a recent paper it is claimed that vacuum birefringence has been experimentally observed for the first time by measuring the degree of polarization of visible light from a magnetar candidate, a neutron star with a magnetic field presumably as large as 10^13 G. The role of such a strong magnetic field is twofold. First, the surface of the star emits, at each point, polarized light with linear polarization correlated with the orientation of the magnetic field. Depending on the relative orientation of the magnetic axis of the star with the direction to the distant observer, a certain degree of polarization should be visible. Second, the strong magnetic field in the vacuum surrounding the star could enhance the effective degree of polarization observed: vacuum birefringence. We compare experimental data and theoretical expectations concluding that the conditions to support a claim of strong evidence of vacuum birefringence effects are not met.
2017
euler-heisenberg; magnetar; isolated; neutron; star; vacuum; birefringence; bayesian
01 Pubblicazione su rivista::01a Articolo in rivista
A note on polarized light from magnetars / Capparelli, L. M.; Damiano, A.; Maiani, L.; Polosa, A. D.. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - ELETTRONICO. - 77:11(2017), p. 754. [10.1140/epjc/s10052-017-5342-3]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1018166
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