Generating a perfect quantum optical vortex
  In this article we introduce a novel quantum state, the perfect quantum optical vortex state which exhibits a highly localised distribution along a ring in the quadrature space. We examine its nonclassical properties using the Wigner function and the negativity volume. Such a quantum state can be a useful resource for quantum information processing and communication. 
Anindya Banerji, Ravindra Pratap Singh, Dhruba Banerjee and Abir   Bandyopadhyay
quant-ph physics.optics