Fig. 1 (IMAGE) Science China Press Caption The wave steering applications based on topological states. (a) The negative refraction of sound wave based on topological surface state. (b) The acoustic interferometer based on topological hinge states. Credit ©Science China Press Usage Restrictions Use with credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.