661 research outputs found
Revivals and oscillations of the momentum of light in a planar multimode waveguide
The evolution of the transverse momentum of monochromatic light entering a multimode planar waveguide at large angle is investigated. We report on oscillations of the momentum caused by the beatings between the adjacent populated modes of the waveguide and their periodic collapses and revivals. A new type of an interferometer based on this effect with fringe spacing as small as 1/9 of a light wavelength is demonstrated experimentally and periods as small as 1/1000 of a light wavelength seem to be feasible
Heavy fermion and Kondo lattice behavior in the itinerant ferromagnet CeCrGe3
Physical properties of polycrystalline CeCrGe and LaCrGe have
been investigated by x-ray absorption spectroscopy, magnetic susceptibility
, isothermal magnetization M(H), electrical resistivity ,
specific heat C() and thermoelectric power S() measurements. These
compounds are found to crystallize in the hexagonal perovskite structure (space
group \textit{P6/mmc}), as previously reported. The ,
and C() data confirm the bulk ferromagnetic ordering of itinerant Cr moments
in LaCrGe and CeCrGe with = 90 K and 70 K respectively. In
addition a weak anomaly is also observed near 3 K in the C() data of
CeCrGe. The T dependences of and finite values of Sommerfeld
coefficient obtained from the specific heat measurements confirm that
both the compounds are of metallic character. Further, the dependence of
of CeCrGe reflects a Kondo lattice behavior. An enhanced
of 130 mJ/mol\,K together with the Kondo lattice behavior inferred from
the establish CeCrGe as a moderate heavy fermion compound with
a quasi-particle mass renormalization factor of 45.Comment: 7 pages, 7 figures. Accepted by Journal of Physics: Condensed Matte
Coupling a single electron to a Bose-Einstein condensate
The coupling of electrons to matter is at the heart of our understanding of
material properties such as electrical conductivity. One of the most intriguing
effects is that electron-phonon coupling can lead to the formation of a Cooper
pair out of two repelling electrons, the basis for BCS superconductivity. Here
we study the interaction of a single localized electron with a Bose-Einstein
condensate (BEC) and show that it can excite phonons and eventually set the
whole condensate into a collective oscillation. We find that the coupling is
surprisingly strong as compared to ionic impurities due to the more favorable
mass ratio. The electron is held in place by a single charged ionic core
forming a Rydberg bound state. This Rydberg electron is described by a
wavefunction extending to a size comparable to the dimensions of the BEC,
namely up to 8 micrometers. In such a state, corresponding to a principal
quantum number of n=202, the Rydberg electron is interacting with several tens
of thousands of condensed atoms contained within its orbit. We observe
surprisingly long lifetimes and finite size effects due to the electron
exploring the wings of the BEC. Based on our results we anticipate future
experiments on electron wavefunction imaging, investigation of phonon mediated
coupling of single electrons, and applications in quantum optics.Comment: 4 pages, 3 figures and supplementary informatio
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