5,492 research outputs found
Periods of activity cycles in late-type stars
The mean magnetic field dynamo theory is utilized to obtain the qualitative dependence of the period of activity on the angular velocity of rotation for stars with sufficiently extensive convective shells. The dependence of the cycle period on the spectral class is also discussed
Pseudo-epsilon expansion and the two-dimensional Ising model
Starting from the five-loop renormalization-group expansions for the
two-dimensional Euclidean scalar \phi^4 field theory (field-theoretical version
of two-dimensional Ising model), pseudo-\epsilon expansions for the Wilson
fixed point coordinate g*, critical exponents, and the sextic effective
coupling constant g_6 are obtained. Pseudo-\epsilon expansions for g*, inverse
susceptibility exponent \gamma, and g_6 are found to possess a remarkable
property - higher-order terms in these expansions turn out to be so small that
accurate enough numerical estimates can be obtained using simple Pade
approximants, i. e. without addressing resummation procedures based upon the
Borel transformation.Comment: 4 pages, 4 tables, few misprints avoide
Phase Transitions in liquid Helium 3
The phase transitions of liquid Helium 3 are described by truncations of an
exact nonperturbative renormalization group equation. The location of the first
order transition lines and the jump in the order parameter are computed
quantitatively. At the triple point we find indications for partially universal
behaviour. We suggest experiments that could help to determine the effective
interactions between fermion pairs.Comment: 4 pages, 6 figures, LaTe
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