New variational perturbation theory based on $q-$deformed oscillator
  A new variational perturbation theory is developed based on the $q-$deformed oscillator. It is shown that the new variational perturbation method provides 200 or 10 times better accuracy for the ground state energy of anharmonic oscillator than the Gaussian and the improved Gaussian approximation, respectively. 
Hyeong-Chan Kim, Jae Hyung Yee, and Sang Pyo Kim