»ã±¨±êÌâ (Title)£ºPattern Formation and Exotic Order in Driven-Dissipative Bose-Hubbard Systems£¨ÔÚÇý¶¯-ºÄÉ¢µÄ²£É«-¹þ²®µÂϵͳÖеÄͼ°¸½á¹¹²úÉúºÍ±ðÖÂÐò£©

»ã±¨ÈË (Speaker)£º²Ì×Ó ×êÑÐÔ±£¨ÉϺ£½»Í¨´óѧ£©

»ã±¨¹¦·ò (Time)£º2021Äê10ÔÂ19ÈÕ(Öܶþ) 10:30-12:00

»ã±¨µØÖ· (Place)£ºÐ£±¾²¿G309

Ô¼ÇëÈË(Inviter)£ºÕÅÓÀƽ

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»ã±¨ÌáÒª£ºModern experimental platforms such as superconducting circuit arrays call for the exploration of bosonic tight-binding models in unconventional situations with no counterpart in real materials. Here we investigate one such situation in which excitations are driven and damped by pairs, leading to pattern formation and exotic bosonic states emerging from a nonequilibrium quantum many-body system. Focusing on a two-dimensional driven-dissipative Bose-Hubbard model, we find that its steady states are characterized by the condensation of bosons around momenta lying on a ¡°Bose surface,¡± a bosonic analog of the Fermi surface in solid-state systems. The interplay between instabilities generated by the driving, the nonlinear dissipative mode coupling, and the underlying lattice effect allows the system to equilibrate into an exotic superfluid state of bosons condensed on a closed ring in momentum space instead of discrete points. Such an unconventional state with a spatially uniform density distribution goes beyond the traditional scope of pattern formation and thus has no counterpart in the classical literature.