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About

About

I am Full Professor at the Department of Informatics at the University of Minho, and senior researcher at the High Assurance Software Laboratory (HASLab INESC TEC). Since October 2016, I am also serving as Deputy Head of UNU-EGOV, the United Nations University Operational Unit on Policy-driven Electronic Governance (egov.unu.edu).

My research interests are focused on program semantics and calculi applied to systems understanding and rigorous software construction. I am particularly interested in coalgebra theory and conductive reasoning, as well as on modal and hybrid logics.

In recent years I coordinated four research projects at the national level, bilateral partnerships with Brazil and China, and served as the Portuguese coordinator for the Language Engineering and Rigorous Software Development ALFA EU-Latin America network, a PhD training network funded by the European Union. I have published five book chapters, 25 journal papers and more than 60 international conference papers. Having served as invited lecturer in MSc and PhD programmes at the Universities of Bristol (United Kingdom), Tartu (Estonia), and Peking (China), I have supervised several PhD projects (six concluded; four on-going). One of my students, Alexandre Madeira, received the 2013 IBM Scientific Prize, the biggest award in Informatics in Portugal.

I integrated the founding team of the Joint Doctoral Programme in Computer Science of the Universities of Minho, Aveiro, and Porto (MAP-i), and served as its Director. I am a member of IFIP WG1.3 (Foundations of System Specification), and, since January 2019, chair of IFIP Tecnhical Committee TC1 on Foundations of Computer Science.

Currently, I am leading the Quantum Software Engineering Research Group at INL, the International Iberian Nanotechnology Laboratory.

Interest
Topics
Details

Details

  • Name

    Luís Soares Barbosa
  • Role

    Research Coordinator
  • Since

    01st November 2011
003
Publications

2025

Specification of paraconsistent transition systems, revisited

Authors
Cunha, J; Madeira, A; Barbosa, LS;

Publication
SCIENCE OF COMPUTER PROGRAMMING

Abstract
The need for more flexible and robust models to reason about systems in the presence of conflicting information is becoming more and more relevant in different contexts. This has prompted the introduction of paraconsistent transition systems, where transitions are characterized by two pairs of weights: one representing the evidence that the transition effectively occurs and the other its absence. Such a pair of weights can express scenarios of vagueness and inconsistency. . This paper establishes a foundation for a compositional and structured specification approach of paraconsistent transition systems, framed as paraconsistent institution. . The proposed methodology follows the stepwise implementation process outlined by Sannella and Tarlecki.

2024

On Quantum Natural Policy Gradients

Authors
Sequeira, A; Santos, LP; Barbosa, LS;

Publication
IEEE TRANSACTIONS ON QUANTUM ENGINEERING

Abstract
This article delves into the role of the quantum Fisher information matrix (FIM) in enhancing the performance of parameterized quantum circuit (PQC)-based reinforcement learning agents. While previous studies have highlighted the effectiveness of PQC-based policies preconditioned with the quantum FIM in contextual bandits, its impact in broader reinforcement learning contexts, such as Markov decision processes, is less clear. Through a detailed analysis of L & ouml;wner inequalities between quantum and classical FIMs, this study uncovers the nuanced distinctions and implications of using each type of FIM. Our results indicate that a PQC-based agent using the quantum FIM without additional insights typically incurs a larger approximation error and does not guarantee improved performance compared to the classical FIM. Empirical evaluations in classic control benchmarks suggest even though quantum FIM preconditioning outperforms standard gradient ascent, in general, it is not superior to classical FIM preconditioning.

2024

Digital quantum simulation of non-perturbative dynamics of open systems with orthogonal polynomials

Authors
Guimaraes, JD; Vasilevskiy, MI; Barbosa, LS;

Publication
QUANTUM

Abstract
Classical non-perturbative simulations of open quantum systems' dynamics face several scalability problems, namely, exponential scaling of the computational effort as a function of either the time length of the simulation or the size of the open system. In this work, we propose the use of the Time Evolving Density operator with Orthogonal Polynomials Algorithm (TEDOPA) on a quantum computer, which we term as Quantum TEDOPA (Q-TEDOPA), to simulate nonperturbative dynamics of open quantum systems linearly coupled to a bosonic environment (continuous phonon bath). By performing a change of basis of the Hamiltonian, the TEDOPA yields a chain of harmonic oscillators with only local nearestneighbour interactions, making this algorithm suitable for implementation on quantum devices with limited qubit connectivity such as superconducting quantum processors. We analyse in detail the implementation of the TEDOPA on a quantum device and show that exponential scalings of computational resources can potentially be avoided for time-evolution simulations of the systems considered in this work. We applied the proposed method to the simulation of the exciton transport between two light-harvesting molecules in the regime of moderate coupling strength to a non-Markovian harmonic oscillator environment on an IBMQ device. Applications of the Q-TEDOPA span problems which can not be solved by perturbation techniques belonging to different areas, such as the dynamics of quantum biological systems and strongly correlated condensed matter systems.

2024

Secure two-party computation via measurement-based quantum computing

Authors
Rahmani, Z; Pinto, AHMN; Barbosa, LMDCS;

Publication
QUANTUM INFORMATION PROCESSING

Abstract
Secure multiparty computation (SMC) provides collaboration among multiple parties, ensuring the confidentiality of their private information. However, classical SMC implementations encounter significant security and efficiency challenges. Resorting to the entangled Greenberger-Horne-Zeilinger (GHZ) state, we propose a quantum-based two-party protocol to compute binary Boolean functions, with the help of a third party. We exploit a technique in which a random Z-phase rotation on the GHZ state is performed to achieve higher security. The security and complexity analyses demonstrate the feasibility and improved security of our scheme compared to other SMC Boolean function computation methods. Additionally, we implemented the proposed protocol on the IBM QisKit and found consistent outcomes that validate the protocol's correctness.

2024

Quantum advantage in temporally flat measurement-based quantum computation

Authors
de Oliveira, M; Barbosa, LS; Galvao, EF;

Publication
QUANTUM

Abstract
Several classes of quantum circuits have been shown to provide a quantum computational advantage under certain assumptions. The study of ever more restricted classes of quantum circuits capable of quantum advantage is motivated by possible simplifications in experimental demonstrations. In this paper we study the efficiency of measurement-based quantum computation with a completely flat temporal ordering of measurements. We propose new constructions for the deterministic computation of arbitrary Boolean functions, drawing on correlations present in multi-qubit Greenberger, Horne, and Zeilinger (GHZ) states. We characterize the necessary measurement complexity using the Clifford hierarchy, and also generally decrease the number of qubits needed with respect to previous constructions. In particular, we identify a family of Boolean functions for which deterministic evaluation using non-adaptive MBQC is possible, featuring quantum advantage in width and number of gates with respect to classical circuits.

Supervised
thesis

2023

Timing Constraints in Quantum Programming Languages

Author
Vítor Emanuel Gonçalves Fernandes

Institution
UM

2023

Time-structure in measurement-based quantum computation

Author
Michael de Oliveira

Institution
UM

2023

Continuous-time Quantum Walks

Author
Jaime Pereira Santos

Institution
UM

2022

Quantum Reinforcement Learning: Foundations, algorithms, applications

Author
André Manuel Resende Sequeira

Institution
UM

2022

Quantum Bayesian Reinforcement Learning

Author
Gilberto Rui Nogueira Cunha

Institution
UM