Gravitational Waves and Extra Dimensions: A Short Review**Supported by the National Natural Science Foundation of China under Grant Nos. 11875151 and 11522541; the Fundamental Research Funds for the Central Universities under Grant No. lzujbky-2018-k11; and the scholarship granted by the Chinese Scholarship Council

Abstract

We give a brief review on the recent development of gravitational waves in extra-dimensional theories of gravity. Studying extra-dimensional theories with gravitational waves provides a new way to constrain extra dimensions. After a flash look at the history of gravitational waves and a brief introduction to several major extra-dimensional theories, we focus on the sources and spectra of gravitational waves in extra-dimensional theories. It is shown that one can impose limits on the size of extra dimensions and the curvature of the universe by researching the propagations of gravitational waves and the corresponding electromagnetic waves. Since gravitational waves can propagate throughout the bulk, how the amplitude of gravitational waves decreases determines the number of extra dimensions for some models. In addition, we also briefly present some other characteristics of gravitational waves in extra-dimensional theories.