Strongly interacting bosons in a one-dimensional disordered lattice: Phase coherence of distorted Mott phases

Year: 2024

Authors: Chakrabarti B., Gammal A., Salasnich L.

Autors Affiliation: Presidency Univ, Dept Phys, 86-1 Coll St, Kolkata 700073, India; Univ Sao Paulo, Inst Fis, BR-05508090 Sao Paulo, SP, Brazil; Univ Padua, Dipartimento Fis Galileo Galilei, INFN Sezione Padova, Sez Padova, Padua, Italy; CNR INO Unita Sesto Fiorentino, Pisa, Italy.

Abstract: We explore the consequences of disorder on phase coherence in the Mott insulator phases in an optical lattice. Few bosons with contact interaction in small optical lattice can feature varieties of insulating phases-weakly interacting Mott in deep lattice, maximally fragmented and strongly interacting Mott in intermediate lattice, weak Mott with double filling and intrawell coherence, fermionized Mott with strong intrawell coherence. Utilization of the multiconfigurational time-dependent Hartree method for bosons to solve the many-boson Schr & ouml;dinger equation, facilitates to understand the microscopic effect of disorder on the different kinds of Mott phases in the primary lattice. The many-body properties are analyzed by distinct measures of the reduced one-body density in real and momentum space, fragmentation, order parameter, variance of spatial single-shot measurements, compressibility, and the Glauber normalized correlation functions. We find very complex competition of localization due to disorder and Mott correlation. We observe distinct response of four different Mott phases in the disordered lattice. When the weakly interacting Mott exhibits the Bose glass phase, the strongly correlated and fully fragmented Mott exhibits leakage, melting and central localization. In contrast, weak Mott with double filling which is a spatially separated dimer in each site, exhibits only some dissociation of intrawell coherence and assist in the development of interwell coherence in the presence of strong disorder. For the fermionized Mott, when the density in each well is fragmented, strong disorder interferes with the intrawell correlation and the characteristic dip in each site starts to disappear leading to simple Mott localization with a pair of bosons.

Journal/Review: PHYSICAL REVIEW B

Volume: 110 (18)      Pages from: 184202-1  to: 184202-14

More Information: B.C. acknowledges significant discussion of results with P. Molignini, Sk. Noor Nabi, S. Basu, and P. Sengupta. L.S. acknowledges the BIRD Project Ultracold atoms in curved geometries of the University of Padova. L.S. is partially supported by the European Union-NextGenerationEU within the National Center for HPC, Big Data and Quantum Computing (Project No. CN00000013, CN1 Spoke 10: Quantum Computing) and by the European Quantum Flagship Project PASQuanS 2. L.S. acknowle dges Iniziativa Specifica Quantum of Istituto Nazionale di Fisica Nucleare, the Project Frontiere Quantistiche within the 2023 funding programme Dipartimenti di Eccellenza of the Italian Ministry for Universities and Research, and the PRIN 2022 Project Quantum Atomic Mixtures: Droplets, Topological Structures, and Vortices. B.C. and A.G. thank Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) , Grant No. 2023/06550-4. A.G. also thanks the funding from Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) , Grant No. 306219/2022-0.
KeyWords: Anderson Localization; Insulator
DOI: 10.1103/PhysRevB.110.184202