Observing complementary Lucas sequences using non-Hermitian zero modes

The Lucas sequences are integers defined by a homogeneous recurrence relation. They include the well-known Fibonacci numbers, which appear abundantly in nature. The complementary Lucas numbers, defined by the same recurrence relation, are less well-known. In this work, we show that a special case of such complementary Lucas sequences can be observed on the same physical platform. It consists of a gain-and-loss-modulated non-Hermitian reservoir bridging two mirror-symmetric systems, which manifests the Lucas sequences in linearly localized edge states and a constant-intensity mode, respectively.