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Updated: Jun 23, 2026
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Published on: April 8, 2020
Quantum Monte Carlo method for the Bose-Hubbard model with harmonic confining potential
Yasuyuki Kato1, Naoki Kawashima
1Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwa-no-ha, Kashiwa, Chiba 277-8581, Japan.
Summary
We simulated large Bose-Hubbard systems, observing superfluid coherence between two spheres. This work models cold atomic Bose gases in optical lattices, advancing quantum simulation capabilities.
Area of Science:
- Quantum simulation
- Condensed matter physics
- Cold atom physics
Background:
- The Bose-Hubbard model describes interacting bosons in a lattice.
- Cold atomic Bose gases in optical lattices are key quantum simulators.
- Simulating large systems is computationally challenging.
Purpose of the Study:
- To study the Bose-Hubbard model with an external harmonic field.
- To develop efficient simulation methods for large quantum systems.
- To investigate coherence phenomena in novel quantum gas structures.
Main Methods:
- Modification of the directed-loop algorithm for efficient large-scale simulations.
- Simulation of a Bose-Hubbard system with 1.8 x 10^5 particles on a 64^3 lattice.
- Analysis of coherence between superfluid regions separated by insulating barriers.
Main Results:
- Demonstration of efficient simulation of large Bose-Hubbard systems.
- Observation of quantum coherence between two distinct superfluid spheres.
- Characterization of a "wedding-cake" structure with superfluid and Mott insulator regions.
Conclusions:
- The modified directed-loop algorithm enables efficient simulation of large quantum systems.
- Coherence between separated superfluid regions is achievable and observable.
- This research provides insights into quantum phase transitions and superfluidity in engineered atomic gases.
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