Programme

O.38 -- Oral, VCTP-51

Date: Thursday, 6 August 2026

Time: 14:40 - 15:00

VARIATIONAL QUANTUM SIMULATION OF THE BOSE-HUBBARD MODEL

HO XUAN NHAT (1), TRAN MINH DUC(1), PHAM VAN ANH(1), HO KHAC HIEU(1), NGUYEN QUANG SAN(2), DUNG VAN LU(1)

(1) Faculty of Physics and Chemistry, The University of Danang - University of Science and Education, Da Nang City; (2) School of Engineering and Technology - Hue University, Hue City.

The Bose–Hubbard model serves as a fundamental quantum model for studying strongly interacting bosonic systems, quantum phase transitions, and many-body correlation phenomena. However, the efficient encoding and representation of bosonic quantum states on quantum hardware remain significant challenges due to differences in quantum architectures and encoding strategies. In this work, the Bose–Hubbard model is investigated using the Variational Quantum Eigensolver (VQE) algorithm on two quantum computing architectures based on qubits and qumodes. In terms of computational resources, qubit encoding requires a number of qubits proportional to $n$ (with $n=[\text{log}_2 ⁡D]$), whereas qumode encoding requires a number of modes equal to the number of lattice sites. The findings highlight the trade-off between the Hilbert-space compression capability of qubit-based encoding and the natural Fock-space representation offered by qumode-based encoding. These results provide useful guidance for selecting appropriate quantum architectures for the simulation of many-body bosonic systems.

Presenter: Dụng-Văn Lữ