Year: 2025
Type: article
Abstract: This work provides a physical explanation for the existence of a ``ghost'' plasmon in bilayer superconductors. The authors show that one of the two Josephson plasmons is connected to counterflowing current fluctuations polarized perpendicularly to the planes. This effect makes it a transverse mode at small out-of-plane momenta, explaining why it is hidden in the density response. This work offers a new perspective on the understanding of collective excitations in systems with multiple intertwined degrees of freedom.
Authors: Niccolò Sellati, Lara Benfatto
Institution: Sapienza University of Rome
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: Sapienza Università di Roma
OpenAlex ID: W4408505274