Dr. Sk Sazim, Harish Chandra Research Institute, Allahabad gave  Journal Club talk on Coherence Makes Quantum Systems ‘Magical’ on 5 April.

What makes quantum technologies more powerful than their classical counterparts? We argue that the linear superposition principle, implying the existence of quantum coherence, can be intuitively thought of as the driving agent behind any quantum advantage.

Two primary facets of quantum technological advancement that holds great promise are quantum communication and quantum computation. For quantum communication, the canonical resource is entanglement. For quantum gate implementation, the resource is ‘magic’ in an auxiliary system. It has already been shown that quantum coherence is the fundamental resource for the creation of entanglement. We argue on the similar spirit that quantum coherence is the fundamental resource when it comes to the creation of magic. This unifies the two strands of modern development in quantum technology under the common underpinning of the existence of quantum superposition, quantified by the coherence in quantum theory. We also attempt to obtain magic monotones inspired by coherence monotones and vice versa. We further study the interplay between quantum coherence and magic in a qutrit system, and that between quantum entanglement and magic in a qutrit-qubit setting.

Dr. Sk Sazim is currently a postdoctoral fellow in Harish Chandra Research Institute, HRI Allahabad. He obtained his Ph.D in quantum information science from the Institute of Physics, Bhubaneswar in 2016. His current research interests are  Resource theory, Communication protocols and Uncertainty and duality relations.