Beyond-mean-field phases of rotating dipolar condensates

Abstract

Rotating dipolar Bose-Einstein condensates exhibit rich physics due to the interplay of long-range interactions and rotation, leading to unconventional vortex structures and strongly correlated phases. While most studies rely on mean-field approaches, these fail to capture quantum correlations that become significant at high rotation speeds and strong interactions. In this study, we go beyond the mean-field description by employing a numerically exact multiconfigurational approach to study finite-sized dipolar condensates. We reveal novel vortex structures, rotating cluster states, and strong fragmentation effects, demonstrating that beyond-mean-field correlations remain prominent even in larger systems. By quantifying deviations from mean-field theory, we provide a predictive framework for analyzing experiments and exploring emergent quantum phases, with implications for both the fundamental theory of ultracold gases and the quantum simulation of correlated superfluid systems like in neutron stars.

Figures (16)

• Figure 1: The different phases obtained from the simulation of $N=50$ dipolar-interacting bosons in a rotating potential as a function of interaction strength $g_d$ and rotation speed $\Omega$ (on a logarithmic scale). The different panels show results obtained for different number of orbitals: (a) $M=1$ orbitals, (b) $M=2$ orbitals, (c) $M=5$ orbitals. The red letters in the phase diagram refer to the points in parameter space where the density distributions of Fig. \ref{['fig:density-N-50']} were probed.
• Figure 2: The different states appearing for $N=50$ dipolar bosons in a rotating trap: (a) superfluid, (b) fragmented superfluid with angular roton profile, (c) superfluid with a single vortex core, (d) fragmented superfluid with a single vortex core, (e) Abrikosov lattice of vortices, (f) coexistence of deformed vortex lattice with central clusters. The circles in the upper-right corners have the same color code used in the phase diagram \ref{['fig:PD-N-50']} and indicate which states the density represents.
• Figure 3: The difference in ground state energy between different $N=50$ calculations with increasing orbital number: (a) $\delta E = \frac{E_{M=1} - E_{M=2}}{E_{M=1}}$, (b) $\delta E = \frac{E_{M=2} - E_{M=5}}{E_{M=2}}$. The red lines indicate the $\delta E = 0$ contours.
• Figure 4: The IPR in parameter space for $N=50$ calculations with (a) $M=2$ and (b) $M=5$ orbitals.
• Figure 5: The different phases obtained from the simulation of $N=20$ dipolar-interacting bosons in a rotating potential as a function of interaction strength $g_d$ and rotation speed $\Omega$ (on a logarithmic scale). The different panels show results obtained for different number of orbitals: (a) $M=1$ orbitals, (b) $M=2$ orbitals, (c) $M=5$ orbitals. The red letters in the phase diagram refer to the points in parameter space where the density distributions of Fig. \ref{['fig:density-N-20']} were probed.