1,351 research outputs found
Orientation Sensitive Terahertz Resonances Observed in Protein Crystals
A method is presented for measuring anisotropic THz response for small
crystals, Crystal Anisotropy Terahertz Microscopy (CATM). Sucrose CATM
measurements find the expected anisotropic phonon resonances. CATM measurements
of protein crystals find the expected broadband water absorption is suppressed
and strong orientation and hydration dependent resonant features.Comment: 3 page
The Faraday effect revisited: General theory
This paper is the first in a series revisiting the Faraday effect, or more
generally, the theory of electronic quantum transport/optical response in bulk
media in the presence of a constant magnetic field. The independent electron
approximation is assumed. At zero temperature and zero frequency, if the Fermi
energy lies in a spectral gap, we rigorously prove the Widom-Streda formula.
For free electrons, the transverse conductivity can be explicitly computed and
coincides with the classical result. In the general case, using magnetic
perturbation theory, the conductivity tensor is expanded in powers of the
strength of the magnetic field . Then the linear term in of this
expansion is written down in terms of the zero magnetic field Green function
and the zero field current operator. In the periodic case, the linear term in
of the conductivity tensor is expressed in terms of zero magnetic field
Bloch functions and energies. No derivatives with respect to the quasi-momentum
appear and thereby all ambiguities are removed, in contrast to earlier work.Comment: Final version, accepted for publication in J. Math. Phy
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