Quantization of bending waves in a living nematic

Living nematic is a realization of an active matter combining a nematic liquid crystal with swimming bacteria. Self-organized bending waves emerge from the initial uniform alignment with a characteristic length controlled by a balance between bacteria activity and anisotropic viscoelasticity of liquid crystal. In this work, we study living nematic confined in a circular track. The wavelengths of the observed waves depend on both bacterial activity and confinement size. In contrast to quasi-infinite systems, in which the wavelength of periodic director instability is a continuous function of bacteria activity, in this work, we only observed instabilities with quantized wavelengths. Transitions between different states associated with different wavelengths are triggered by changes in bacterial activity.