arXiv subjects

Bruno Oziel Fernandez

Publications and source records attributed to Bruno Oziel Fernandez.

4 recordsLinked to original sources

arXiv2026

Molecular Docking with Quantum Circuit Evolution

Molecular docking is an important step in drug discovery, enabling the evaluation of receptor-ligand affinity while reducing experimental costs and increasing the number of possible tests. However, the high computational cost associated with molecular docking remains a limiting factor that can restrict both the experimental precision and the scale of the problems being addressed. To improve the future applicability of molecular docking, recent works have proposed the use of quantum algorithms based on Gaussian Boson Sampling quantum computers and also gate-based quantum computers. In this work, we propose the use of Quantum Circuit Evolution (QCE) for solving the molecular docking problem, a gate based and gradient-free quantum evolutionary method whose evolution is driven by the random application of unitary operations to a quantum circuit. The proposed algorithm demonstrated the ability to find the best solution to the problem in fewer steps than the methods presented in previous studies, exhibiting fast and stable convergence.

quant-ph↗

arXiv2025

Quantum circuit evolutionary framework applied on set partitioning problem

Quantum algorithms are of great interest for their possible use in optimization problems. In particular, variational algorithms that use classical counterparts to optimize parameters hold promise for use in currently existing devices. However, convergence stagnation phenomena pose a challenge for such algorithms. Seeking to avoid such difficulties, we present a framework based on circuits with variable topology with two approaches, one based on ansatz-free evolutionary method known from literature and the other using an introduction of an ansatz with circuital structure inspired by the physics of the Hamiltonian related to the problem, considering a, named here, pseudo-counterdiabatic evolutionary term. The efficiency of the proposed framework was tested on several instances of the set partitioning problem. The two approaches were compared with the Variational Quantum Eigensolver in noisy and non-noisy scenarios. The results demonstrated that optimization using circuits with variable topology presented very encouraging results. Notably, the strategy employing a pseudo-counterdiabatic evolutionary term exhibited remarkable performance, avoiding convergence stagnation in most instances considered. This framework circumvents the need for classical optimizers, and, as a consequence, this procedure based on circuits with variable topology indicates an interesting path in the search for algorithms to solve integer optimization problems targeting efficient applications in larger-scale scenarios.

quant-ph↗

arXiv2025

Avoiding convergence stagnation in a quantum circuit evolutionary framework through an adaptive cost function

Binary optimization problems are emerging as potential candidates for useful applications of quantum computing. Among quantum algorithms, the quantum approximate optimization algorithm (QAOA) is currently considered the most promising method to obtain a quantum advantage for such problems. The QAOA method uses a classical counterpart to perform optimization in a hybrid approach. In this paper, we show that the recently introduced method called quantum circuit evolutionary (QCE) also has potential for applications in binary optimization problems. This methodology is classical optimizer-free, but, for some scenarios, may have convergence stagnation as a consequence of smooth circuit modifications at each generation. To avoid this drawback and accelerate the convergence capabilities of QCE, we introduce a framework using an adaptive cost function (ACF), which varies dynamically with the circuit evolution. This procedure accelerates the convergence of the method. Applying this new approach to instances of the set partitioning problem, we show that QCE-ACF achieves convergence performance identical to QAOA but with a shorter execution time. Finally, experiments in the presence of induced noise show that this framework is quite suitable for the noisy intermediate-scale quantum era.

quant-ph↗

arXiv2024

Exploiting the Variational Quantum Eigensolver for Determining Ground State Energy of Protocatechuic Acid

The Variational Quantum Eigensolver (VQE) is a promising hybrid algorithm, utilizing both quantum and classical computers to obtain the ground state energy of molecules. In this context, this study applies VQE to investigate the ground state of protocatechuic acid, analyzing its performance with various Ansätze and active spaces. Subsequently, all VQE results were compared to those obtained with the Hartree-Fock (HF) method. The results demonstrate that Ansätze, like unitary coupled-cluster singles and doubles (UCCSD) and variations of Hardware-Efficient, generally achieve accuracy close to that of HF. Furthermore, the increase in active space has led to the models becoming more difficult to converge to values with a greater distance from the correct energy. In summary, the findings of this study reinforce the use of VQE as a powerful tool for analyzing molecular ground state energies. Finally, the results underscore the critical importance of Ansatz selection and active space size in VQE performance, providing valuable insights into its potential and limitations.

physics.chem-ph↗