Longitudinal electromechanical pulses and their interactions near phase transitions

• Applicant: Professor Dr. Matthias F. Schneider
• Subject Area: Statistical Physics, Nonlinear Dynamics, Complex Systems, Soft and Fluid Matter, Biological Physics
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 539638202

The superposition principle for waves fails when a system is driven close to a phase transition. This was recently demonstrated by us upon measuring pulse annihilation of colliding pulses in lipid monolayers. This evidence suggests that novel nonlinear properties of sound, such as pulse-pulse interactions as well as a new class of (nonlinear) Chladni figures, may emerge close to the phase transition. Our goal is to study the phenomenology of these interactions with various techniques experimentally and extract the underlying physical mechanisms theoretically. To this end, experiments on pulse propagation in monomolecular films (lipid monolayers) as well as solid-supported lipid bilayers driven by surface acoustic waves near phase transitions will be performed and combined with theoretical models integrating the physico-chemical properties of such films or membranes, respectively. To achieve this goal we will investigate the role of phase transitions on the propagation and interaction of nonlinear longitudinal pulses from different angles: (1) How do colliding longitudinal pulses interact near phase transitions? (2) How do pulses propagate in a phase separated system? and (3) How does a phase transition impact standing waves? Our theoretical models combine hydrodynamics, electrical and chemical couplings and (experimentally accessible) phenomenological constitutive expressions in an attempt to get closer to a universal physical description of sound in 2D near phase transitions.

• DFG Programme: Research Grants
• International Connection: Israel
• International Co-Applicant: Professor Dr. Matan Mussel