У оквиру семинара Центра за изучавање комплексних система Института за физику у Београду, у четвртак, 28. октобра 2021. године у 14 часова путем Zoom платформе, Милан Крстајић (Лабораторија Кларендон, Универзитет у Оксфорду), одржаће предавање:
Experimental platform for a box-trapped dipolar quantum gas
Dipolar quantum gases make up an increasingly popular branch within an already thriving field of ultracold quantum gases. The interest in such systems lies in a multitude of quantum phenomena that stem from dipole-dipole interactions, particularly from their long-range and anisotropic nature. This talk describes the design and building of an experimental platform for investigating many-body physics in homogeneous dipolar quantum gases of erbium. We will present results on the progress towards reaching the goal of an erbium Bose-Einstein condensate in an optical box potential, including the performance of laser cooling methods and the optical systems for optical trapping and transport. At present, the experiment is capable of producing clouds with 100 million atoms at the temperature of 15 microkelvin in the magneto-optical trap, which translates into about 15 million atoms at 50 microkelvin following transfer into an optical dipole trap. We will discuss details on the remaining steps to complete the platform and present an overview of the research topics our platform will make accessible, including roton physics and supersolidity, out-of-equilibrium many-body phenomena and dynamics of phase transitions in systems with long-range interactions. We will also briefly touch upon the subject of expanding the apparatus to a dual-species experiment with potassium, which will enable investigating systems with impurities. Finally, we will extend the discussion to results from numerical simulations on the stability of a purely dipolar quantum gas against collapse in a general power-law trap (of which the optical box is an example), showing that intermediate power-law traps lead to maximally homogeneous density distributions for near-critical interaction strengths.