Symmetric ordering effect on Casimir energy in $\kappa-$Minkowski   spacetime
  We present the Casimir energy of spherical shell, for the symmetrically deformed scalar field in $\kappa$-Minkowski space-time, satisfying Dirichlet boundary condition. The Casimir energy shows the particle anti-particle symmetry contrary to the asymmetrically deformed case. In addition, the deformation effect starts from $O(1/\kappa)$ term unlike in the parallel plates. 
Hyeong-Chan Kim, Chaiho Rim, and Jae Hyung Yee