Departamento de Óptica

Jan 22, 2024 | link.aps.org | Departamento de Óptica |Facultad de Física |Universidad Complutense

Majorana stars, the 2S spin coherent states that are orthogonal to a spin-S state, offer an elegant method to visualize quantum states, disclosing their intrinsic symmetries. These states are naturally described by the corresponding multipoles. These quantities can be experimentally determined and allow for an SU(2)-invariant analysis. We investigate the relationship between Majorana constellations and state multipoles, thus providing insights into the underlying symmetries of the system.

Jul 18, 2023 | link.aps.org | Nicolas Fabre |Departamento de Óptica |Eloi Descamps

Abstract We study the role of the electromagnetic field’s frequency on the precision limits of time measurements from a quantum perspective, using single photons as a paradigmatic system. We demonstrate that a quantum enhancement of precision is possible only when combining both intensity and spectral resources and, in particular, that spectral correlations enable a quadratic scaling of precision with the number of probes.

Jul 12, 2023 | link.aps.org | Nicolas Fabre |Departamento de Óptica |Facultad de Física |Universidad Complutense

Abstract Majorana stellar representation, which visualizes a quantum spin as points on the Bloch sphere, allows quantum mechanics to accommodate the concept of trajectory, the hallmark of classical physics. We extend this notion to the discrete cylinder, which is the phase space of the canonical pair angle and orbital angular momentum. We demonstrate that the geometrical properties of the ensuing constellations aptly encapsulate the quantumness of the state.