In the presence of indefinite causal order, two identical copies of a completely depolarizing channel can transmit non-zero information. This arises due to quantum superposition of two alternative orders of quantum channels. Here, we address the question: Can we transmit perfect classical information with superposition...

Quantum mechanics ensures that the information stored in a quantum state is secure and the ability to send private information through a quantum channel is at least as great as the coherent information. We derive trade- off relations between quantum privacy, information gain by Eve and the disturbance caused by Eve to the quantum state that is being sent through a noisy channel. For tripartite quantum states, we show that monogamy of privacy exists in the case of a single sender and multiple receivers. When Alice prepares a tripartite...

We study an important measure of correlation i.e., quantum discord, that uses the Von Neumann Entropy to determine the correlation analytically for general states. A quantum state can possess the classical as well as quantum correlation where the difference of it results in quantumness of correlation. We do a detailed study of quantum discord, a difference in two classically equivalent forms of mutual information, introduced by Ollivier and Zurek. We furthermore....