Atomic manybody phase transitions and quantum criticality have recently attracted much attention in nonstandard optical lattices. Here we perform an experimental study of finite temperature superfluid transition of bosonic atoms confined in a three dimensional triangular lattice, whose structure can be continuously deformed to dimensional crossover regions including quasione and two dimensions. This nonstandard lattice system provides a versatile platform to investigate manybody correlated phases. For the three dimensional case, we find that the finite temperature superfluid transition agrees quantitatively with the Gutzwiller mean field theory prediction, whereas tuning towards reduced dimensional cases, both quantum and thermal fluctuation effects are more dramatic, and the experimental measurement for the critical point becomes strongly deviated from the mean field theory. We characterize the fluctuation effects in the whole dimension crossover process. Our experimental results imply strong manybody correlations in the system beyond mean field description, paving a way to study quantum criticality near Mottsuperfluid transition in finite temperature dimensioncrossover lattices.
 Award ID(s):
 1846109
 Publication Date:
 NSFPAR ID:
 10320816
 Journal Name:
 Nature Communications
 Volume:
 12
 Issue:
 1
 ISSN:
 20411723
 Sponsoring Org:
 National Science Foundation
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