Formation of matter-wave soliton trains by modulational instability

Abstract

Nonlinear systems can exhibit a rich set of dynamics that are inherently sensitive to their initial conditions. One such example is modulational instability, which is believed to be one of the most prevalent instabilities in nature. By exploiting a shallow zero-crossing of a Feshbach resonance, we characterize modulational instability and its role in the formation of matter-wave soliton trains from a Bose-Einstein condensate. We examine the universal scaling laws exhibited by the system and, through real-time imaging, address a long-standing question of whether the solitons in trains are created with effectively repulsive nearest-neighbor interactions or rather evolve into such a structure.

Three-Component Soliton States in Spinor F=1 Bose-Einstein Condensates

“…Among the various systems that support solitons, dilute-gas Bose-Einstein condensates (BECs) [2,3] provide a particularly versatile testbed for the investigation of solitonic structures [4][5][6]. In single-component BECs, solitons have been observed either as robust localized pulses (bright solitons) [7][8][9][10][11] or density dips in a background matter wave (dark solitons) [12][13][14][15][16][17][18][19][20][21], typically in BECs with attractive or repulsive interatomic interactions, respectively. Extending such studies to two-component BECs has led to rich additional dynamics.…”

One-dimensional Bose gas dynamics: Breather relaxation

“…In these systems, there is evidence of steady-states that do not have a Gibbs structure [15,16]. Attractive matter-wave solitons have also been experimentally observed [17][18][19][20][21][22].Here we show that the dynamical stability of higherorder matter-wave solitons prepared by quenching is experimentally testable. Fragmentation and damping of breathing oscillations [23,24] are predicted to persist even up to a mean particle number of N = 1000.…”

“…Known conserved quantities are replicated with high accuracy. This is a regime accessible to current BEC experiments [22,24,28]. We show that direct experimental tests of predictions for soliton fragmentation and centerof-mass dynamics are possible in an exponentially complex regime where exact calculation is extremely difficult.…”

“…In these systems, there is evidence of steady-states that do not have a Gibbs structure [15,16]. Attractive matter-wave solitons have also been experimentally observed [17][18][19][20][21][22].…”

“…The present protocol employs a localized non-interacting BEC as the initial state, following earlier proposals [29,30]. The timescales and numbers used are within the general parameter range achievable with current 7 Li [22] and 85 Rb [28] ultra-cold atomic physics experiments.…”