SAMOP 2023 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 26: Quantum Gases: Bosons III
Q 26.2: Vortrag
Mittwoch, 8. März 2023, 11:15–11:30, E214
Quantum Critical Behavior of Entanglement in Lattice Bosons with Cavity-Mediated Long-Range Interactions — •Simon B. Jäger1,2, Shraddha Sharma2,3, Rebecca Kraus2, Tommaso Roscilde4, and Giovanna Morigi2 — 1Physics Department, Technische Universität Kaiserslautern — 2Theoretische Physik, Saarland University — 3ICTP-The Abdus Salam International Center for Theoretical Physics — 4Univ. Lyon, Ens de Lyon, CNRS, Laboratoire de Physique
We analyze the ground-state entanglement entropy of the extended Bose-Hubbard model with infinite-range interactions. This model describes the low-energy dynamics of ultracold bosons tightly bound to an optical lattice and dispersively coupled to a cavity mode. The competition between on-site repulsion and global cavity-induced interactions leads to a rich phase diagram, which exhibits superfluid, supersolid, and insulating phases. We use a slave-boson treatment of harmonic quantum fluctuations around the mean-field solution and calculate the entanglement entropy across the phase transitions. At commensurate filling, the insulator-superfluid transition is signaled by a singularity in the area-law scaling coefficient of the entanglement entropy, which is similar to the one reported for the standard Bose-Hubbard model. Remarkably, at the continuous Z2 superfluid-to-supersolid transition we find a critical logarithmic term, regardless of the filling. This behavior originates from the appearance of a roton mode in the excitation and entanglement spectrum, becoming gapless at the critical point, and it is characteristic of collective models.