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V. A. Piatrou

Publications and source records attributed to V. A. Piatrou.

7 recordsLinked to original sources
arXiv2011

Asymmetric double well system as effective model for the kicked one

Effective Hamiltonian for the kicked double well system was derived using the Campbell-Baker-Hausdorff expansion formula. Asymmetric model for the kicked system was constructed. Analytical description of the quasienergy levels splittings for the low laying doublets was given in the framework of the model. Numerical calculations confirm applicability of the proposed effective asymmetric approach for the double well system with the kick-type perturbation.

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arXiv2011

Chaotic instantons and enhancement of tunneling in double-well system with polychromatic perturbation

Chaotic instanton approach allows to describe analytically the influence of the polychromatic perturbation on quantum properties of nonlinear systems. Double well system with single, multiple and polychromatic kicked perturbation is considered in the paper to compare quantitative analytical predictions with the results of numerical calculations. Chaotic instantons are responsible for the enhancement of tunneling far away from the exact (avoided) level crossings in framework of the approach used. Time-independent averaged system is used for regular approximation of the chaotic instanton solution in order to take into account its contribution to the ground quasienergy doublet splitting. Formula for the ground quasienergy levels' splitting was derived averaging trajectory action in the stochastic layer in the framework of chaotic instanton approach. Results of quasienergy spectrum numerical calculations and simulations for tunneling dynamics are in good agreement with the obtained analytical predictions.

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arXiv2010

Chaotic instantons and enhancement of tunneling in kicked double-well system with time-reversal symmetry

Chaotic instanton approach is used to describe dynamical tunneling in kicked double well system. Effective Hamiltonian for the kicked system is obtained using matrix expansion formula for operator exponent and exploited to construct an approximation for chaotic instanton solution. This approximation is used for derivation of the ground quasienergy splitting dependence on both the perturbation strength and frequency. Results of numerical calculations for corresponding ground quasienergy splitting dependencies based on Floquet theory are in good agreement with the derived analytical formula in a wide range of perturbation parameters.

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arXiv2008

Chaotic instantons in periodically perturbed double-well system

Kicked double-well system is investigated both analytically and numerically. Phenomenological formula for ground quasienergy splitting is obtained using resonances overlap criterion in the framework of chaotic instanton approach. Results of numerical calculations of quasienergy spectrum are in good agreement with the phenomenological formula.

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arXiv2007

Stability of Yang-Mills fields system in the homogeneous (anti-)self-dual background field

Stability of Yang-Mills fields system in the background field is investigated basing on Toda criterion, Poincare sections and the values of the maximal Lyapunov exponents. The existence of the region of regular motion at low densities of energy is demonstrated. Critical energy density of the order-chaos transition is analyzed for the different values of the model parameter.

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arXiv2003

The influence of quantum field fluctuations on chaotic dynamics of Yang--Mills system

On example of the model field system we demonstrate that quantum fluctuations of non-abelian gauge fields leading to radiative corrections to Higgs potential and spontaneous symmetry breaking can generate order region in phase space of inherently chaotic classical field system. We demonstrate on the example of another model field system that quantum fluctuations do not influence on the chaotic dynamics of non-abelian Yang--Mills fields if the ratio of bare coupling constants of Yang--Mills and Higgs fields is larger then some critical value. This critical value is estimated.

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