title: Dynamical Majorana edge modes in a broad class of topological mechanical systems.
abstract: Mechanical systems can display topological characteristics similar to that of topological insulators. Here we report a large class of topological mechanical systems related to the BDI symmetry class. These are self-assembled chains of rigid bodies with an inversion centre and no reflection planes. The particle-hole symmetry characteristic to the BDI symmetry class stems from the distinct behaviour of the translational and rotational degrees of freedom under inversion. This and other generic properties led us to the remarkable conclusion that, by adjusting the gyration radius of the bodies, one can always simultaneously open a gap in the phonon spectrum, lock-in all the characteristic symmetries and generate a non-trivial topological invariant. The particle-hole symmetry occurs around a finite frequency, and hence we can witness a dynamical topological Majorana edge mode. Contrasting a floppy mode occurring at zero frequency, a dynamical edge mode can absorb and store mechanical energy, potentially opening new applications of topological mechanics.
authors.affiliation: Department of Physics, Yeshiva University, New York, New York 10016, USA.
authors.forename: Emil
authors.initials: E
authors.lastname: Prodan
authors.affiliation: Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102, USA.
authors.forename: Kyle
authors.initials: K
authors.lastname: Dobiszewski
authors.affiliation: Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102, USA.
authors.forename: Alokik
authors.initials: A
authors.lastname: Kanwal
authors.affiliation: Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, New Jersey 07102, USA.
authors.forename: John
authors.initials: J
authors.lastname: Palmieri
authors.affiliation: Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102, USA.
authors.forename: Camelia
authors.initials: C
authors.lastname: Prodan