2019/02/05 by Petkov, Vesselin, Tzvetkov, Nikolay
#35L15 (Secondary) #35L71 (Primary) #Analysis of PDEs (math.AP) #FOS: Mathematics #FOS: Physical sciences #Mathematical Physics (math-ph)
paper · doi:10.48550/arxiv.1902.01680
We consider the Cauchy problem for the nonlinear wave equation utt - Δx u +q(t, x) u + u3 = 0 with smooth potential q(t, x) ≥ 0 having compact support with respect to x. The linear equation without the nonlinear term u3 and potential periodic in t may have solutions with exponentially increasing as t → ∞ norm H1(\mathbb R3x). In [2] it was established that adding the nonlinear term u3 the H1(\mathbb R3x) norm of the solution is polynomially bounded for every choice of q. In this paper we show that Hk(\mathbb R3x) norm of this global solution is also polynomially bounded. To prove this we apply a different argument based on the analysis of a sequence \Yk(nτk)\n = 0∞ with suitably defined energy norm Yk(t) and 0 < τk <1.