The PVLAS collaboration is presently assembling a new apparatus to detect vacuum magnetic birefringence. This property is related to the structure of the QED vacuum and is predicted by the Euler-Heisenberg-Weisskopf effective Lagrangian. It can be detected by measuring the ellipticity acquired by a linearly polarised light beam propagating through a strong magnetic field. Here we report results of a scaled-down test setup and briefly describe the new PVLAS apparatus. This latter one is in construction and is based on a high-sensitivity ellipsometer with a high-finesse Fabry-Perot cavity $(> 4\times10^5)$ and two 0.8 m long 2.5 T rotating permanent dipole magnets. Measurements with the test setup have improved by a factor 2 the previous upper bound on the parameter $A_e$, which determines the strength of the nonlinear terms in the QED Lagrangian: $A^{\rm (PVLAS)}_e < 3.3 \times10^{21}~{\rm T}^{-2}$ 95\% c.l.
The PVLAS experiment: detecting vacuum magnetic birefringence / G., Zavattini; DELLA VALLE, Federico; U., Gastaldi; G., Messineo; Milotti, Edoardo; R., Pengo; L., Piemontese; G., Ruoso. - In: JOURNAL OF PHYSICS. CONFERENCE SERIES. - ISSN 1742-6588. - STAMPA. - 442:(2013), pp. 012057.012057-1-012057.012057-14. [10.1088/1742-6596/442/1/012057]
The PVLAS experiment: detecting vacuum magnetic birefringence
DELLA VALLE, FEDERICO;MILOTTI, EDOARDO;
2013-01-01
Abstract
The PVLAS collaboration is presently assembling a new apparatus to detect vacuum magnetic birefringence. This property is related to the structure of the QED vacuum and is predicted by the Euler-Heisenberg-Weisskopf effective Lagrangian. It can be detected by measuring the ellipticity acquired by a linearly polarised light beam propagating through a strong magnetic field. Here we report results of a scaled-down test setup and briefly describe the new PVLAS apparatus. This latter one is in construction and is based on a high-sensitivity ellipsometer with a high-finesse Fabry-Perot cavity $(> 4\times10^5)$ and two 0.8 m long 2.5 T rotating permanent dipole magnets. Measurements with the test setup have improved by a factor 2 the previous upper bound on the parameter $A_e$, which determines the strength of the nonlinear terms in the QED Lagrangian: $A^{\rm (PVLAS)}_e < 3.3 \times10^{21}~{\rm T}^{-2}$ 95\% c.l.Pubblicazioni consigliate
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