Motion (physics)

Symmetry breaking

Explicit symmetry breaking

Quantum mechanics

Theoretical physics

Engineering

Philosophy

Computer science

Classical mechanics

Mechanical engineering

Physics

Symmetry operation

Mathematics

Epistemology

Spontaneous symmetry breaking

Artificial intelligence

Geometry

Rotational symmetry

Combinatorics

Point (geometry)

Symmetry (geometry)

Topology (electrical circuits)

Mechanics

Hermitian matrix

Property (philosophy)

Mechanical system

Physical review. B./Physical review. B

We propose mechanical systems, described by Newton's equation of motion, as suited platforms for symmetry protection of non-Hermitian topological degeneracies. We point out that systems possess emergent symmetry, which is a unique properties of mechanical systems. Because of the emergent symmetry, in contrast to other systems, fine-tuning of parameters (e.g., gain and loss) is not required to preserve the symmetry protecting exceptional rings in two dimensions. The presence of symmetry-protected exceptional rings (SPERs) in two dimensions is numerically demonstrated for a mechanical graphene with friction. Furthermore, classification of symmetry-protected non-Hermitian degeneracies is addressed by taking into account the above special characteristics of mechanical systems.

Exceptional rings protected by emergent symmetry for mechanical systems