Bonn 2025 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 26: Poster – Precision Measurement, Metrology, and Quantum Effects

Q 26.1: Poster

Dienstag, 11. März 2025, 14:00–16:00, Tent

Real-Space Dynamical Mean-Field Theory Analysis of the Disordered Bose-Hubbard Model — •Bastian Schindler, Renan da Silva Souza, and Walter Hofstetter — Goethe-Universität, Institut für Theoretische Physik, 60438 Frankfurt am Main, Germany

We numerically investigate the two-dimensional Bose-Hubbard model with local onsite disorder, where the competition between disorder and short-range interactions leads to the emergence of a Bose Glass (BG) phase between the Mott Insulator (MI) and superfluid (SF) phases [1]. In order to solve the inhomogeneous system we employ real-space bosonic dynamical mean-field theory [2] and include the stochastic nature of the system via an ensemble average over disorder realizations. To distinguish the MI from the BG phase we compare the Edwards-Anderson order parameter and the compressibility with the energy gap condition [3]. To find the insulator to SF transition we apply a percolation analysis to the condensate order parameter. In accordance with the theorem of inclusions [3] we always find an intermediate BG phase between the SF and MI. Analyzing the spectral function in the strong coupling regime reveals evidence for analytically predicted damped localized modes in the dispersion relation [4].

[1] M. P. A. Fisher et al., Physical Review B 40, 546 (1989)

[2] M. Snoek and W. Hofstetter, Quantum Gases (2013)

    https://doi.org/10.1142/9781848168121_0023

[3] V. Gurarie et al., Phys. Rev. B 80, 214519 (2009)

[4] R. S. Souza et al., New J. Phys. 25, 063015 (2013)

Keywords: Bose-Hubbard Model; Disordered Systems; Bose Glass; Dynamical Mean Field Theory