The entanglement measure induced by Tsallis relative $$\alpha $$ entropy

Anna Vershynina

Several ways have been proposed in the literature to define a coherence measure based on Tsallis relative entropy. One of them is defined as a distance between a state and a set of incoherent states with Tsallis relative entropy taken as a distance measure. Unfortunately, this measure does not satisfy the required strong monotonicity, but a modification of this coherence has been proposed that does. We introduce three new Tsallis coherence measures coming from a more general definition that also satisfy the strong monotonicity, and compare all five definitions between each other. Using three coherence measures that we discuss, one can also define a discord. Two of these have been used in the literature, and another one is new. We also discuss two correlation measures based on Tsallis relative entropy. We provide explicit expressions for all three discord and two correlation measure on pure states. Lastly, we provide tight upper and lower bounds on two discord and correlations measures on any quantum state, with the condition for equality.

Mahboobeh Moslehi, Hamid Reza Baghshahi, Sayyed Yahya Mirafzali

Xue Yang, Yanhan Yang, Zhao Li-ming +1 more

Muthuganesan, R.

This article introduces a new variant of a family of measurement-induced nonlocality (MIN) measures using Tsallis α−relative entropy (TαE). We show that the proposed MIN measure satisfies all the axioms of a faithful measure of quantum correlation and resolves the local ancilla issue of Hilbert–Schmidt MIN. Analytically, we evaluate the MIN for an arbitrary pure state and 2×n-dimensional mixed state. We also establish the simple relations between Tsallis MIN and the other MINs available in the literature. Extending the notion of the Tsallis entropy–based MIN, we characterize the nonbilocal correlation in a bilocal scenario and identify the closer connection between the nonlocal and nonbilocal correlation measures.

Chanyong Park B

Anna Vershynina

Relative entropy of coherence can be written as an entropy difference of the original state and the incoherent state closest to it when measured by relative entropy. The natural question is, if we generalize this situation to Tsallis or Rényi entropies, would it define good coherence measures? In other words, we define a difference between Tsallis entropies of the original state and the incoherent state closest to it when measured by Tsallis relative entropy. Taking Rényi entropy instead of the Tsallis entropy, leads to the well-known distance-based Rényi coherence, which means this expression defined a good coherence measure. Interestingly, we show that Tsallis entropy does not generate even a genuine coherence monotone, unless it is under a very restrictive class of operations. Additionally, we provide continuity estimates for both Tsallis and Rényi coherence expressions. Furthermore, we present two coherence measures based on the closest incoherent state when measures by Tsallis or Rényi relative entropy.