The q-Deformed Harmonic Oscillator, Coherent States, and the Uncertainty   Relation
  For a q-deformed harmonic oscillator, we find explicit coordinate representations of the creation and annihilation operators, eigenfunctions, and coherent states (the last being defined as eigenstates of the annihilation operator). We calculate the product of the coordinate momentum uncertainties in qoscillator eigenstates and in coherent states. For the oscillator, this product is minimum in the ground state and equals 1/2, as in the standard quantum mechanics. For coherent states, the $q$-deformation results in a violation of the standard uncertainty relation; the product of the coordinate- and momentumoperator uncertainties is always less than 1/2. States with the minimum uncertainty, which tends to zero, correspond to the values of $\lambda$ near the convergence radius of the $q$-exponential. 
V.V Eremin, A.A. Meldianov