| 翻訳と辞書 |
PVLAS
PVLAS (Polarizzazione del Vuoto con LASer, "polarization of the vacuum with laser") is an experiment for the detection of dark matter at the Legnaro National Laboratory of the National Institute of Nuclear Physics near Padova, Italy. It searches for vacuum polarization causing nonlinear optical behavior in magnetic fields, indicating effects from unseen particles such as axions. Experiments began in 2001 and continue today with new equipment.
== Background ==
As dark matter does not emit or reflect any electromagnetic radiation which may be directly detected, PVLAS searches for nonlinear effects on light in the vacuum, predicted by the Euler-Heisenberg Lagrangian in 1936. In the presence of a massive dark matter candidate that interacts with the photon, like the axion, virtual dark matter particles will be preferentially created by photons with polarization parallel to the external field. These virtual particles travel slower than light, so the effective speed of the photons with a parallel polarization is reduced. Thus the vacuum is birefringent, its index of refraction depends on polarization. PVLAS looks for the flattening of a linearly polarised laser beam after it passes through a vacuum with an intense magnetic field.〔(''The PVLAS experiment'' )〕 This flattening is characteristic of light in a birefringent medium. The birefrigence of the vacuum in quantum electrodynamics by an external field is generally credited to Stephen L. Adler, who presented the first general derivation in (Photon splitting and photon dispersion in a strong magnetic field ) in 1971.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「PVLAS」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|