Scaling in activated escape of underdamped systems

Noise-induced escape from a metastable state of a dynamical system is studied close to a saddle-node bifurcation point, but in the region where the system remains underdamped. The activation energy of escape scales as a power of the distance to the bifurcation point. We find two types of scaling and the corresponding critical exponents.Comment: 9 page

Schiff moment of the Mercury nucleus and the proton dipole moment

We calculated the contribution of internal nucleon electric dipole moments to the Schiff moment of $^{199}$Hg. The contribution of the proton electric dipole moment was obtained via core polarization effects that were treated in the framework of random phase approximation with effective residual forces. We derived a new upper bound $|d_p|< 5.4\times 10^{-24} e\cdot$cm of the proton electric dipole moment.Comment: 4 pages, 2 figures, RevTex

Theory of microwave-induced oscillations in the magnetoconductivity of a 2D electron gas

We develop a theory of magnetooscillations in the photoconductivity of a two-dimensional electron gas observed in recent experiments. The effect is governed by a change of the electron distribution function induced by the microwave radiation. We analyze a nonlinearity with respect to both the dc field and the microwave power, as well as the temperature dependence determined by the inelastic relaxation rate.Comment: Extended version of cond-mat/0310668. 12 pages, 4 figures. V2: published version (minor changes, Fig. 4 corrected, references added

On relativistic approaches to the pion self-energy in nuclear matter

We argue that, in contrast to the non-relativistic approach, a relativistic evaluation of the nucleon--hole and delta-isobar--nucleon hole contributions to the pion self-energy incorporates the s-wave scattering, which requires a more accurate evaluation. Therefore relativistic approach containing only these diagrams does not describe appropriately the pion self-energy in isospin symmetric nuclear matter. We conclude that, a correct relativistic approach to the pion self-energy should involve a more sophisticated calculation in order to satisfy the known experimental results on the near-threshold behaviour of the pion-nucleon (forward) scattering amplitude.Comment: 7 pages,1 figur

P- and T-violating Schiff moment of the Mercury nucleus

The Schiff moment of the $^{199}$Hg nucleus was calculated using finite range P- and T-violating weak nucleon-nucleon interaction. Effects of the core polarization were considered in the framework of RPA with effective residual forces.Comment: 10 pages and 2 figures,to appear in Yad. Fi