Duan Jinqiao, Fu X. C., Liu P. D., Manning A. On a Linear Chaotic Quantum Harmonic Oscillator (15K, LaTeX) ABSTRACT. We show that a linear quantum harmonic oscillator is chaotic in the sense of Li-Yorke. We also prove that the weighted backward shift map, used as an infinite dimensional linear chaos model, in a separable Hilbert space is chaotic in the sense of Li-Yorke, in addition to being chaotic in the sense of Devaney.