Physics

Reciprocity (cultural anthropology)

Dispersion relation

Rectification

Band gap

Psychology

Power (physics)

Acoustic metamaterials

Acoustics

Condensed matter physics

Lattice (music)

Quantum mechanics

Diode

Social psychology

Physical Review Letters

Acoustic waves in a linear time-invariant medium are generally reciprocal; however, reciprocity can break down in a time-variant system. In this Letter, we report on an experimental demonstration of nonreciprocity in a dynamic one-dimensional phononic crystal, where the local elastic properties are dependent on time. The system consists of an array of repelling magnets, and the on-site elastic potentials of the constitutive elements are modulated by an array of electromagnets. The modulation in time breaks time-reversal symmetry and opens a directional band gap in the dispersion relation. As shown by experimental and numerical results, nonreciprocal mechanical systems like the one presented here offer opportunities to create phononic diodes that can serve for rectification applications.

Observation of Nonreciprocal Wave Propagation in a Dynamic Phononic Lattice