12,603 research outputs found
Equilibrium magnetization in the vicinity of the first order phase transition in the mixed state of high-Tc superconductors
We present the results of a scaling analysis of isothermal magnetization M(H)
curves measured in the mixed state of high-Tc superconductors in the vicinity
of the established first order phase transition. The most surprising result of
our analysis is that the difference between the magnetization above and below
the transition may have either sign, depending on the particular chosen sample.
We argue that this observation, based on M(H) data available in the literature,
is inconsistent with the interpretation that the well known first order phase
transition in the mixed state of high-Tc superconductors always represents the
melting transition in the vortex system.Comment: 4 pages, 5 figure
Excitation of atomic hydrogen to the metasable 2 2S1/2 state by electron impact
Atomic hydrogen excitation to metastable 2 /2/ S sub 1/2 state by electron impac
Polarization of Lyman alpha radiation emitted by H/2S/ atoms in weak electric fields
Polarization prediction in modulated beam of ground state hydrogen atoms crossed by dc electron bea
Optical evidence for a spin-filter effect in the charge transport of
We have measured the optical reflectivity of
as a function of temperature between 1.5 and 300
and in external magnetic fields up to 7 . The slope at the onset of the
plasma edge feature in increases with decreasing temperature and
increasing field but the plasma edge itself does not exhibit the remarkable
blue shift that is observed in the binary compound . The analysis of
the magnetic field dependence of the low temperature optical conductivity
spectrum confirms the previously observed exponential decrease of the
electrical resistivity upon increasing, field-induced bulk magnetization at
constant temperature. In addition, the individual exponential magnetization
dependences of the plasma frequency and scattering rate are extracted from the
optical data.Comment: submitted to Phys. Rev. Let
Continuous-wave spatial quantum correlations of light induced by multiple scattering
We present theoretical and experimental results on spatial quantum
correlations induced by multiple scattering of nonclassical light. A continuous
mode quantum theory is derived that enables determining the spatial quantum
correlation function from the fluctuations of the total transmittance and
reflectance. Utilizing frequency-resolved quantum noise measurements, we
observe that the strength of the spatial quantum correlation function can be
controlled by changing the quantum state of an incident bright squeezed-light
source. Our results are found to be in excellent agreement with the developed
theory and form a basis for future research on, e.g., quantum interference of
multiple quantum states in a multiple scattering medium.Comment: 8 pages, 6 figure
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