Article Dans Une Revue Astronomy & Astrophysics - A&A Année : 2024

PT and anti-PT symmetries for astrophysical waves

Résumé

Context: Discrete symmetries have found numerous applications in photonics and quantum mechanics, but remain little studied in fluid mechanics, particularly in astrophysics. Aims: We aim to show how PT and anti-PT symmetries determine the behaviour of linear perturbations in a wide class of astrophysical problems. They set the location of Exceptional Points in the parameter space and the associated transitions to instability, and are associated to the conservation of quadratic quantities that can be determined explicitly. Methods: We study several classical local problems: the gravitational instability of isothermal spheres and thin discs, the Schwarzschild instability, the Rayleigh-Bénard instability and acoustic waves in dust-gas mixtures. We calculate the locations and the order of the Exceptional Points with a method of resultant, as well as the conserved quantities in the different regions of the parameter space using Krein theory. Results: All problems studied here exhibit discrete symmetries, even though Hermiticity is broken by different physical processes (self-gravity, buoyancy, diffusion, drag). This analysis provides genuine explanations for certain instabilities, and for the existence of regions in the parameter space where waves do not propagate. Those correspond to breaking of PT and anti-PT symmetries respectively. Not all instabilities are associated to symmetry breaking (e.g. the Rayleigh-Benard instability).

Fichier principal
Vignette du fichier
aa48710-23.pdf (652.64 Ko) Télécharger le fichier
Origine Fichiers éditeurs autorisés sur une archive ouverte
Licence

Dates et versions

hal-04617008 , version 1 (17-01-2025)

Licence

Identifiants

Citer

Armand Leclerc, Guillaume Laibe, Nicolas Perez. PT and anti-PT symmetries for astrophysical waves. Astronomy & Astrophysics - A&A, 2024, 689, pp.A237. ⟨10.1051/0004-6361/202348710⟩. ⟨hal-04617008⟩
96 Consultations
55 Téléchargements

Altmetric

Partager

  • More