Crystallization, Fermionization, and Cavity-Induced Phase Transitions of Bose-Einstein Condensates

Bose-Einstein condensates (BECs) are one of the cornerstones in the exploration of the quantum many-body physics of interacting indistinguishable particles. Here, we study them using the MultiConfigurational Time-Dependent Hartree for Bosons (MCTDHB) method implemented in the MCTDHB and MCTDH-X software packages using the Cray XC40 system Hazel Hen. In this year we investigated the physics of (i) fermionization and crystallization of ultracold strongly interacting bosons, (ii) correlations of bosons with strong dipolar interactions, (iii) cavity-induced phase transitions of ultracold bosons in high-finesse cavities, (iv) the dimensionality of the variance of BECs in annular confinements, (v) the dynamics of BECs with long-ranged interactions in a bosonic Josephson junction, (vi) the dynamics of BECs in an asymmetric bosonic Josephson junction, (vii) the variance of BECs in anharmonic traps. All these results are novel and intriguing findings that demonstrate the versatility of the MCTDHB method, its implementations in the MCTDHB and MCTDH-X software packages, and how extremely fruitful the computational resources at the HLRS system Hazel Hen were for the MCTDHB project there. For the sake of brevity, we restrict the present report to the results (i)–(iii). We conclude with an outline for possible future avenues in the development revolving around MCTDHB and MCTDH-X.