Laboratory of Information Technologies

Seminar of the Scientific Department of Computational Physics

Date and Time: Friday, 14 March 2025, at 11:00 AM

Venue: room 310, Meshcheryakov Laboratory of Information Technologies, online on Webinar

Link to join the seminar

Seminar topic: “Variational formalism for oscillons and breathers”

Speaker: Igor Barashenkov

Abstract:

Oscillons are long-lived localised pulsating states in the nonlinear Klein-Gordon equations. The authors formulate a multiscale variational method for the analysis of oscillons that is free from singularities that marred all previously proposed variational techniques. For the model with a symmetric vacuum, a single-harmonic variational Ansatz provides an excellent agreement with the numerical results. For a model with broken symmetry (the equation φ⁴), the numerical analysis reveals that the energy-frequency diagram of the standing wave is fragmented into disjoint segments with frequencies ω_n+1<ω<ω_n. In the interval (ω_n+1, ω_n), the wave develops small-amplitude wings consisting of the n-th harmonic radiation (n = 2, 3, …). The variational approximation involving the first, zeroth and second harmonic components provides an accurate description of the oscillon with the frequency in (ω₃, ω₂), but breaks down as ω falls out of that interval.