Browsing by Author "Bamba, Kazuharu"

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Cosmological birefringence due to CPT-even Chern-Simons-like term with Kalb-Ramond and scalar fields
(2015-05-05)
Ho, Shih-Hao
;
Kao, W. F.
;
Bamba, Kazuharu
;
Geng, C. Q.
;
物理研究所
We study the CPT-even dimension-six Chern-Simons-like term by including dynamical Kalb-Ramond and scalar fields to examine the cosmological birefringence. We show that the combined effect of a neutrino current and a Kalb-Ramond field could induce a sizable rotation polarization angle in the cosmic microwave background radiation polarization.
Large-scale magnetic fields from inflation due to a CPT-even Chern-Simons-like term with Kalb-Ramond and scalar fields
(2012-04-01)
Bamba, Kazuharu
;
Geng, C. Q.
;
Ho, S. H.
;
Kao, W. F.
;
物理研究所
We investigate the generation of large-scale magnetic fields due to the breaking of the conformal invariance in the electromagnetic field through the CPT-even dimension-six Chern-Simons-like effective interaction with a fermion current by taking account of the dynamical Kalb-Ramond and scalar fields in inflationary cosmology. It is explicitly demonstrated that magnetic fields on 1 Mpc scale with the field strength of similar to 10(-9) G at the present time can be induced.