2025/05/12 by Zhen‐Guo Liu, Liu, Z., Xiaozhang Zhu +17
Engineering · Physics and Astronomy · #Acoustic Wave Phenomena Research #Applied Physics (physics.app-ph) #FOS: Physical sciences #Quantum many-body systems #Topological Materials and Phenomena
paper · pdf · doi:10.48550/arxiv.2505.07160
openalex publication_date 2025/05/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Floquet time crystals, characterized by momentum gaps (k-gaps), have sparked intense interest across various branches of physics due to their intriguing dynamics and promising applications. Despite growing theoretical efforts, the realization and observation of phononic time crystals, especially for airborne sound, remain significant experimental challenges. In this work, we demonstrate a phononic time crystal by integrating discrete resonant meta-atoms into a one-dimensional acoustic waveguide, effectively creating a homogeneous, time-varying metamaterial. By dynamically modulating the effective compressibility, we experimentally observe exponential acoustic wave amplification, offering clear evidence of k-gap formation. Furthermore, we showcase the versatility of our platform by inducing momentum band folding and double k-gap phenomena via quasi-periodic temporal modulation. This flexible and reconfigurable approach not only enables the design of tailor-made resonant responses but also opens new avenues for realizing higher-dimensional phononic time crystals and exploring nontrivial topological dynamics in time-modulated media.