https://doi.org/10.1140/epja/s10050-026-01853-0
Regular Article –Theoretical Physics
Entropy-driven entanglement forging
1
Departament de Física, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
2
Barcelona Supercomputing Center, 08034, Barcelona, Spain
3
Departament de Física Quàntica i Astrofísica, Universitat de Barcelona, 08028, Barcelona, Spain
4
Institut de Ciències del Cosmos, Universitat de Barcelona, 08028, Barcelona, Spain
5
Qilimanjaro Quantum Tech, 08007, Barcelona, Spain
a
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Received:
4
February
2026
Accepted:
4
April
2026
Published online:
5
May
2026
Abstract
Simulating physical systems with variational quantum algorithms is a well-studied approach, but it is challenging to implement in current devices due to demands in qubit number and circuit depth. However, limited knowledge of a system can reduce the cost of these algorithms. We demonstrate that the computational overhead in simulating many-body systems can be systematically decreased by leveraging the system’s symmetries, which guide the choice of iterative entanglement forging partitions aligned with the underlying entropy structure. To do so, we simulate a Fermi-Hubbard one-dimensional chain with a parametrized hopping term, as well as atomic nuclei 
Ne and 
Ti with the nuclear shell model. Within an adaptive variational quantum eigensolver setting, we propose an algorithm that employs partitions and subpartitions of the quantum circuit to reduce significantly the quantum resources compared to a fully-fledged simulation. Entropy-driven entanglement forging (EDEF) does not require access to the full statevector or exact entropies; in hardware it is implemented via standard EF expectation-reconstruction rules with crossed statistics, while statevector access is used here only as a classical simulation shortcut. We find that the maximum number of qubits can be reduced by up to a factor of four and we observe an order of magnitude decrease in the number of two-qubit gates compared to regular simulations. Our findings indicate that our method, entropy-driven entanglement forging, can be used to adjust quantum simulations to the limitations of noisy intermediate-scale quantum devices.
Communicated by D. Lacroix.
© The Author(s) 2026
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