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  • Open Access

Time-optimal control of a GdW30 molecular spin qudit

Marc Alsina*

Ibério de P. R. Moreira†

Guillermo Albareda‡

Josep Maria Bofill§

  • Departament de Química Orgànica i Inorgànica, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain; Institut de Química Teòrica Computacional (IQTC UB), Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain; and IDEADED. S.L., Carrer de la Tecnologia, 35, 08840 Viladecans, Barcelona, Spain

  • Departament de Ciència de Materials i Química Física, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain and Institut de Química Teòrica Computacional (IQTC UB), Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain

  • IDEADED. S.L., Carrer de la Tecnologia, 35, 08840 Viladecans, Barcelona, Spain

  • *Contact author: marc.alsina@ideaded.com
  • †Contact author: i.moreira@ub.edu
  • ‡Contact author: Guillermo.Piquer@ideaded.com
  • §Contact author: jmbofill@ub.edu
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Phys. Rev. A 113, 062603 – Published 2 June, 2026

DOI: https://doi.org/10.1103/c7yr-jrs4

Abstract

Quantum systems with more than two levels, known as qudits, offer enhanced information density and potentially more efficient quantum operations compared with traditional qubits. Among the various physical platforms under investigation, single-molecule magnets (SMMs) stand out due to their intrinsic magnetic anisotropy, long spin-relaxation times, and the natural presence of multiple accessible spin states. In this work, we explore two distinct control strategies for implementing state-to-state transitions within the multilevel structure of SMMs, viz., a resonant magnetic-field manipulation (π-pulse control) and the so-called quantum Zermelo navigation approach, which provides the time-optimal Hamiltonian that transforms a given initial state to a given target state. We present a comparative analysis of these two methods, evaluating their operational efficiency and feasibility for experimental realization. Our results show that, while π-pulse control is limited by strict timing constraints, the Zermelo method faces significant challenges in terms of its physical implementation.

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Phys. Rev. A 113, 062603– Published 2 June, 2026
  • Received 21 November 2025
  • Accepted 31 March 2026
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