Phase engineering of chirped rogue waves in Bose–Einstein condensates with a variable scattering length in an expulsive potential

• Published in: Communications in nonlinear science & numerical simulation Vol. 103; p. 105983
• Main Authors: Kengne, Emmanuel, Malomed, Boris A., Liu, WuMing
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.12.2021; Elsevier Science Ltd
• Subjects: Bose-Einstein condensate; Bose-Einstein condensates; Chairman of the board; Chirp; Chirp rogue wave; Coefficients; Frequency shift; Gross-Pitaevskii equation; Kundu-Eckhaus equation; Matter waves; Modulation; Nonlinear equations; Nonlinear Schrödinger equation; Nonlinearity; Propagation; Scattering; Surface waves; Time dependence; Wave scattering; Chirp rogue wave; Kundu-Eckhaus equation; Nonlinear Schrödinger equation; Bose-Einstein condensate; Gross-Pitaevskii equation
• ISSN: 1007-5704; 1878-7274
• DOI: 10.1016/j.cnsns.2021.105983

We consider a cubic Gross-Pitaevskii (GP) equation governing the dynamics of Bose-Einstein condensates (BECs) with time-dependent coefficients in front of the cubic term and inverted parabolic potential. Under a special condition imposed on the coefficients, a combination of phase-imprint and modified lens-type transformations converts the GP equation into the integrable Kundu-Eckhaus (KE) one with constant coefficients, which contains the quintic nonlinearity and the Raman-like term producing the self-frequency shift. The condition for the baseband modulational instability of CW states is derived, providing the possibility of generation of chirped rogue waves (RWs) in the underlying matter-wave (BEC) model. Using known RW solutions of the KE equation, we present explicit first- and second-order chirped RW states. The chirp of the first- and second-order RWs is independent of the phase imprint. Detailed solutions are presented for the following configurations: (i) the nonlinearity exponentially varying in time; (ii) time-periodic modulation of the nonlinearity; (iii) a stepwise time modulation of the strength of the expulsive potential. Singularities of the local chirp coincide with valleys of the corresponding RWs. The results demonstrate that the temporal modulation of the s-wave scattering length and strength of the inverted parabolic potential can be used to manipulate the evolution of rogue matter waves in BEC.