TY - JOUR AU - Raul Aguero-Santacruz AU - David Bermudez TI - Negative frequencies and negative norms in analogue Hawking radiation systems JO - Comptes Rendus. Physique PY - 2024 PB - Académie des sciences, Paris N1 - Online first DO - 10.5802/crphys.177 LA - en ID - CRPHYS_2024__25_S2_A2_0 ER -