Universality of miscible–immiscible phase separation dynamics in two-component Bose–Einstein condensates

Abstract

We investigate the non-equilibrium dynamics across the miscible-immiscible phase separation in a binary mixture of Bose-Einstein condensates. The excitation spectra reveal that the Landau critical velocity vanishes at the critical point, where the superfluidity spontaneously breaks down. We analytically extract the dynamical critical exponent z=2 and static correlation length critical exponent v=1/2 from the Landau critical velocity. Moreover, by simulating the real-time dynamics across the critical point, we find the average domain number and the average bifurcation delay show universal scaling laws with respect to the quench time. We then numerically extract the static correlation length critical exponent v=1/2 and the dynamical critical exponent z=2 according to Kibble-Zurek mechanism. The scaling exponents (v=1/2, z=2) in the phase separation driven by quenching the atom-atom interaction are different from the ones (v=1/2, z=1) in the phase separation driven by quenching the Rabi coupling strength (2009 Phys. Rev. Lett. 102 070401; 2011 Phys. Rev. Lett. 107 230402). Our study explores the connections between the spontaneous superfluidity breakdown and the spontaneous defect formation in the phase separation dynamics.

Density probabilities of a Bose-Fermi mixture in 1D double well potential

“…We considerer that the initial state of our system is configured, with two spinless soft core bosons and two one half spin fermions in the right side of the double well potential. This configuration is mainly due to the fact that we want to explore the conditions for which is generated the transmutation of bosons into fermions and vice versa, for which the two species are had under the same initial configuration and we varied the boson-boson λ BB , fermion-fermion λ FF and boson-fermion λ BF repulsive contact interaction terms The immiscible and miscible phases for our system is found by means of the probability of finding each species at a point x, at time t. Therefore, an overlap of the probability density of each species indicates that both wave functions occupy the same spatial regions [80].…”

Universal dynamics of superradiant phase transition in the anisotropic quantum Rabi model

“…Due to the gapless excitations at the critical point, the adiabaticity breaks down when a system goes through a continuous phase transition. As a consequence, nontrivial excitations such as domains [4][5][6][7][8][9][10][11][12][13][14], vortices [15][16][17] and solitons [18][19][20] appear spontaneously and obey the wellkonwn Kibble-Zurek mechanism (KZM) [3,4,[21][22][23][24][25]. The KZM has been extensively studied in various systems, from the early universe [3,4], condensed matter systems [26][27][28], trapped ions [29][30][31][32][33], to ultracold atomic gases [5-15, 18-20, 34-37].…”

Kármán vortex street in a two-component Bose–Einstein condensate

“…In the two-component BEC, a variety of dynamical properties have been observed and reported [24][25][26][27][28][29], and the tunable inter-component interaction has been realized experimentally by using the Feshbach resonance technology [30,31]. Especially, the quantized vortices have been created and studied [32][33][34][35][36][37][38][39].…”