6,158 research outputs found
Renormalization programme for effective theories
We summarize our latest developments in perturbative treating the effective
theories of strong interactions. We discuss the principles of constructing the
mathematically correct expressions for the S-matrix elements at a given loop
order and briefly review the renormalization procedure. This talk shall provide
the philosophical basement as well as serve as an introduction for the material
presented at this conference by A. Vereshagin and K. Semenov-Tian-Shansky.Comment: 6 pages, talk given at HSQCD 2004, Russia, May 2004, to be published
in Proceeding
Bootstrap and the Parameters of Pion-Nucleon Resonances
In this talk we demonstrate the results of application of the perturbative
effective theory formalism developed in recent papers to the calculation of
elastic scattering amplitude. Restrictions on the contributing
resonance parameters are obtained and the low energy coefficients are
calculated.Comment: 6 pages, talk given at the X. International Conference On Hadron
Spectroscopy (HADRON'03), August 31 - September 6, 2003, Aschaffenburg,
Germany; to appear in Proceeding
Localizable Effective Theories, Bootstrap and the Parameters of Hadron Resonances
We discuss the basic principles of constructing a meaningful perturbative
scheme for effective theory. The main goal of this talk is to explain the
approach and to present recent results obtained with the help of the method of
Cauchy forms in several complex variables.Comment: 6 pages, Talk given at the X. International Conference On Hadron
spectroscopy (HADRON'03), August 31 - September 6, 2003, Aschaffenburg,
Germany; to appear in Proceeding
Thermal budget of superconducting digital circuits at sub-kelvin temperatures
Superconducting single-flux-quantum (SFQ) circuits have so far been developed
and optimized for operation at or above helium temperatures. The SFQ approach,
however, should also provide potentially viable and scalable control and
read-out circuits for Josephson-junction qubits and other applications with
much lower, milli-kelvin, operating temperatures. This paper analyzes the
overheating problem which becomes important in this new temperature range. We
suggest a thermal model of the SFQ circuits at sub-kelvin temperatures and
present experimental results on overheating of electrons and silicon substrate
which support this model. The model establishes quantitative limitations on the
dissipated power both for "local" electron overheating in resistors and
"global" overheating due to ballistic phonon propagation along the substrate.
Possible changes in the thermal design of SFQ circuits in view of the
overheating problem are also discussed.Comment: 10 pages, 8 figures, submitted to J. Appl. Phy
Rate of steady-state reconnection in an incompressible plasma
The reconnection rate is obtained for the simplest case of 2D symmetric
reconnection in an incompressible plasma. In the short note (Erkaev et al.,
Phys. Rev. Lett.,84, 1455 (2000)), the reconnection rate is found by matching
the outer Petschek solution and the inner diffusion region solution. Here the
details of the numerical simulation of the diffusion region are presented and
the asymptotic procedure which is used for deriving the reconnection rate is
described. The reconnection rate is obtained as a decreasing function of the
diffusion region length. For a sufficiently large diffusion region scale, the
reconnection rate becomes close to that obtained in the Sweet-Parker solution
with the inverse square root dependence on the magnetic Reynolds number,
determined for the global size of the current sheet. On the other hand, for a
small diffusion region length scale, the reconnection rate turns out to be very
similar to that obtained in the Petschek model with a logarithmic dependence on
the magnetic Reynolds number. This means that the Petschek regime seems to be
possible only in the case of a strongly localized conductivity corresponding to
a small scale of the diffusion region.Comment: 11 pages, 3 figure
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