178,006 research outputs found
Non-Loudon-Fleury Raman scattering in spin-orbit coupled Mott insulators
No full textWe revisit the theory of magnetic Raman scattering in Mott insulators with strong spin-orbit coupling,
with a major focus on Kitaev materials. We show that Kitaev materials with bond-anisotropic interactions are
generally expected to show both one- and two-magnon responses. It is further shown that, in order to obtain
the correct leading contributions to the Raman vertex operator R, one must take into account the precise,
photon-assisted microscopic hopping processes of the electrons and that, in systems with multiple hopping
paths, R contains terms beyond those appearing in the traditional Loudon-Fleury theory. Most saliently, a
numerical implementation of the revised formalism to the case of the three-dimensional hyperhoneycomb Kitaev
material β-Li2IrO3 reveals that the non-Loudon-Fleury scattering terms actually dominate the Raman intensity.
In addition, they induce a qualitative modification of the polarization dependence, including, e.g., the emergence
of a sharp one-magnon peak at low energies, which is not expected in the traditional Loudon-Fleury theory. This
peak is shown to arise from microscopic photon-assisted tunneling processes that are of similar type with the
ones leading to the symmetric off-diagonal interaction (known to be present in many Kitaev materials), but
take the form of a bond-directional magnetic dipole term in the Raman vertex. These results are expected to apply
across all Kitaev materials and mark a drastic change of paradigm for the understanding of Raman scattering in
materials with strong spin-orbit coupling and multiple exchange paths
Non-Loudon-Fleury Raman scattering in spin-orbit coupled Mott insulators
No full textWe revisit the theory of magnetic Raman scattering in Mott insulators with strong spin-orbit coupling,
with a major focus on Kitaev materials. We show that Kitaev materials with bond-anisotropic interactions are
generally expected to show both one- and two-magnon responses. It is further shown that, in order to obtain
the correct leading contributions to the Raman vertex operator R, one must take into account the precise,
photon-assisted microscopic hopping processes of the electrons and that, in systems with multiple hopping
paths, R contains terms beyond those appearing in the traditional Loudon-Fleury theory. Most saliently, a
numerical implementation of the revised formalism to the case of the three-dimensional hyperhoneycomb Kitaev
material β-Li2IrO3 reveals that the non-Loudon-Fleury scattering terms actually dominate the Raman intensity.
In addition, they induce a qualitative modification of the polarization dependence, including, e.g., the emergence
of a sharp one-magnon peak at low energies, which is not expected in the traditional Loudon-Fleury theory. This
peak is shown to arise from microscopic photon-assisted tunneling processes that are of similar type with the
ones leading to the symmetric off-diagonal interaction (known to be present in many Kitaev materials), but
take the form of a bond-directional magnetic dipole term in the Raman vertex. These results are expected to apply
across all Kitaev materials and mark a drastic change of paradigm for the understanding of Raman scattering in
materials with strong spin-orbit coupling and multiple exchange paths
Michael Loudon
No full textMichael Loudon retires after 30 years of service. (l-r) President Perry, Michael Loudon, Provost Lordhttps://thekeep.eiu.edu/retirements_2014/1013/thumbnail.jp
Propagation of nonclassical light through an absorbing and dispersive slab
No full textWe calculate the effects of perpendicular propagation through a dispersive and absorbing dielectric slab at arbitrary temperatures on specific nonclassical properties of an incident light field. The transmitted signal is assumed to be measured by a detector that receives radiation only from the direction normal to thr slab surfaces. Squeezing and nonclassical counting statistics of the transmitted light are evaluated for continuous-wave squeezed states incident on both sides of the slab. The degree of second-order coherence is instead evaluated for an N-photon incident pulse, and the effects of transmission through the slab on its antibunching are calculated. [S1050-2947(99)06701-3]
Loudon Wainwright III and Franklin Ajaye poster
No full textColor poster for Loudon Wainwright III and Franklin Ajaye perfomance at Liberty Hall. In the top left of the poster is a photo of Loudon Wainwright III. Next to the photo the text reads: "IN CONCERTTO LOUDON WAINWRIGHT III "DEAD SKUNK IN THE M.O.R." RADIO BROADCAST HOST K P F T STEREO 90 FM". In the middle left of the poster is a photo of Franklin Ajaye. Next to the photo the text reads: "COMEDIANTE & COMICO FRANKLIN AJAYE A and M RECORDS Put A Smile On Your Week Let Your Jaws Drop . . . . . TICKETS AT:-PAISLEY CO, STAFF OF LIFE, U of H BOX OFFICE, EVOLUTION TAOES and RECORDS and LIBERTY HALL BOX OFFICE LIBERTY HALL 1610 CHENEVERT - 225-6250 NOV. 8th 9th 10th 11th 1973 Shows Thurs. & Sun. 8 p. m. Friday and Saturday 8 p. m. & 11 p. m. ADVANCE 3.50".The Houston music venue, Liberty Hall, was open between 1971 and 1978
Electromagnetic field quantization in amplifying dielectrics
No full textThe electromagnetic field is quantized for normal transmission of incident waves through a parallel-sided dielectric slab. The dielectric material is dispersive and it acts as a linear amplifier over limited ranges of the frequency and as a linear attenuator at the remaining frequencies. The field operators derived for the three spatial regions within and on either side of the slab are shown to satisfy the canonical commutation relations. The noise fluxes emitted by the slab are evaluated and shown to satisfy the general requirements for the minimum noise associated with linear amplifiers and attenuators. The behavior of the amplifier gain profile on the approach to the lasing threshold of the slab is determined, but the results are restricted to the below-threshold state of the system. The spectra of the electric-field fluctuations are evaluated for the three spatial regions and for amplifying and attenuating frequencies
Canonical quantum theory of light propagation in amplifying media
No full textWe introduce a quantum theory for the propagation of light through a dielectric slab which acts as a linear amplifier. We show that the theory is canonical, and that self-consistency imposes a natural constraint on the round-trip gain provided by the medium
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