Articles written in Pramana – Journal of Physics

    • Robustness of coherence for multipartite quantum states


      More Details Abstract Fulltext PDF

      In this brief report, we prove that the robustness of coherence (ROC), in contrast with many popular quantitative measures of quantum coherence derived from the resource-theoretic framework of coherence, may be a subadditive for a specific class of multipartite quantum states. We investigate how the subadditivity is affected by admixture with other classes of states for which ROC is superadditive. We show that pairs of quantum states may have different orderings with respect to relative entropy of coherence, $l_{1}$-norm of coherence and ROC and numerically study the difference in ordering for the chosen pairwise coherence measures.

    • Broadcasting of NPT entanglement in two qutrit systems


      More Details Abstract Fulltext PDF

      It is known that beyond $2\otimes 2$ and $2\otimes 3$ dimensional quantum systems, Peres–Hordecki criterion is no longer sufficient as an entanglement detection criterion as there are entangled states with both positive and negative partial transpose (PPT and NPT). Further, it is also true that all PPT entangled states are bound entangled states. However, in the class of NPT states, there exist bound entangled states as well as free entangled states. All free/useful/distillable entanglements are part of the class of NPT entangled states. In this article, we ask the question that given an NPT entangled state in $3\otimes3$ dimensional system as a resource, how much entanglement can we broadcast so that resource still remains NPT. We have chosen $3\otimes3$ system as a first step to understand broadcasting of NPT states in higher dimensional systems. In particular, we find out the range of broadcasting of NPT entanglement for two-parameter class of states (TPCS) and isotropic states (IS). Interestingly, as a derivative of this process we are also able to locate the existence of absolute PPT (ABPPT) states in $3 \otimes 3$ dimensional system. Here we implement the strategy of broadcasting through approximate cloning operations.

  • Pramana – Journal of Physics | News

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2021-2022 Indian Academy of Sciences, Bengaluru.