1,129 research outputs found
Interpretation of experimental data near lambda-transition point in liquid helium
The recently published experimental data for specific heat C_p of liquid
helium in zero gravity conditions very close to the lambda-transition have been
discussed. We have shown that these data allow different interpretations. They
can be well interpreted within the perturbative RG approach and within our
recently developed theory, as well. Allowing the logarithmic correction, the
corresponding fits lie almost on top of each other over the whole range of the
reduced temperatures t (for bin averaged data) 6.3 x 10^{-10} < t < 8.8 x
10^{-3}. However, the plot of the effective exponent alpha_eff(t) suggests that
the behaviour of C_p, probably, changes very close to the lambda-transition
temperature. To clarify this question, we need more accurate data for
t<10^{-7}. In addition, we show that the experimental data for superfluid
fraction of liquid helium close to the critical point within 3 x 10^{-7} < t <
10^{-4} can be better fit by our exponents nu=9/13, Delta=5/13 than by the RG
exponents (nu approximately 0.6705 and Delta about 0.5). The latter ones are
preferable to fit the whole measured range 3 x 10^{-7} < t < 10^{-2} where,
however, remarkable systematic deviations appear. Our estimated value 0.694 +/-
0.017 of the asymptotic exponent nu well agrees with the theoretical prediction
nu=9/13.Comment: 9 pages, 4 figures. The first version was a preliminary one. Now it
is substentially extended and coincides with the published pape
Research on applied bioelectrochemistry First quarterly progress report, 14 Mar. - 30 Jun. 1963
Optimum use of human waste as electrochemical fuels by urea bacterial organism conversion
Narrow Optical and Spin Linewidths in Rare-earth Doped Micro- and Nano-structures
This invited presentation was given at the 47th conference on the Physics of Quantum Electronics, which took place in Snowbird, USA from January 8 to 13, 2017. It gives an overview of the current developments on rare earth doped nanoparticles and transparent ceramics spectroscopy at Chimie ParisTech
Boundary effects on the scaling of the superfluid density
We study numerically the influence of the substrate (boundary conditions) on
the finite--size scaling properties of the superfluid density in
superfluid films of thickness within the XY model employing the Monte Carlo
method. Our results suggest that the jump at the
Kosterlitz--Thouless transition temperature depends on the boundary
conditions.Comment: 2 pages, 1 Latex file, 1 postscript figure, 2 style file
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