김정산 교수

We propose replacing concurrence by convex-roof extended negativity (CREN) for studying monogamy of entanglement (MOE). We show that all proven MOE relations using concurrence can be rephrased in terms of CREN. Furthermore, we show that higher-dimensional (qudit) extensions of MOE in terms of CREN are not disproven by any of the counterexamples used to disprove qudit extensions of MOE in terms of concurrence. We further test the CREN version of MOE for qudits by considering fully or partially co

We show that the restricted shareability and distribution of multiqubit entanglement can be characterized by Tsallis-$q$ entropy. We first provide a class of bipartite entanglement measures named Tsallis-$q$ entanglement, and provide its analytic formula in two-qubit systems for $1\ensuremath{\leqslant}q\ensuremath{\leqslant}4$. For $2\ensuremath{\leqslant}q\ensuremath{\leqslant}3$, we show a monogamy inequality of multiqubit entanglement in terms of Tsallis-$q$ entanglement, and we also provide

We show that restricted shareability of multi-qubit entanglement can be fully characterized by unified-$(q,s)$ entropy. We provide a two-parameter class of bipartite entanglement measures, namely unified-$(q,s)$ entanglement with its analytic formula in two-qubit systems for $q\geq 1$, $0\leq s \leq1$ and $qs\leq3$. Using unified-$(q,s)$ entanglement, we establish a broad class of the monogamy inequalities of multi-qubit entanglement for $q\geq2$, $0\leq s \leq1$ and $qs\leq3$.

Abstract. We generalize the W class of states from n qubits to n qudits and prove that their entanglement is fully characterized by their partial entanglements even for the case of the mixture that consists of a W-class state and a product state |0 〉 ⊗n. PACS numbers: 03.67.-a, 03.65.Ud, Generalized W-Class State and its Monogamy Relation 2 1.

We provide a characterization of multiqubit entanglement constraints in terms of negativity. By using the square of convex-roof extended negativity (SCREN) and the Hamming weight of the binary vector related with the distribution of subsystems, we show that the $\ensuremath{\alpha}\mathrm{th}$ power of SCREN provides a class of monogamy inequalities of multiqubit entanglement in a tight way for $\ensuremath{\alpha}\ensuremath{\ge}1$. We further show that the $\ensuremath{\beta}\mathrm{th}$ power

We establish a unified view of the polygamy of multiparty quantum entanglement in arbitrary dimensions. Using quantum Tsallis-$q$ entropy, we provide a one-parameter class of polygamy inequalities of multiparty quantum entanglement. This class of polygamy inequalities reduces to the known polygamy inequalities based on tangle and entanglement of assistance for a selective choice of the parameter $q$. We further provide one-parameter generalizations of various quantum correlations based on Tsalli

Using entanglement of assistance, we establish a general polygamy inequality of multiparty entanglement in arbitrary-dimensional quantum systems. For multiparty closed quantum systems, we relate our result with the monogamy of entanglement, and clarify that the entropy of entanglement bounds both monogamy and polygamy of multiparty quantum entanglement.

We provide a generalization for the polygamy constraint of multiparty entanglement in arbitrary-dimensional quantum systems. By using the $\ensuremath{\beta}\mathrm{th}$ power of entanglement of assistance for $0\ensuremath{\le}\ensuremath{\beta}\ensuremath{\le}1$ and the Hamming weight of the binary vector related with the distribution of subsystems, we establish a class of weighted polygamy inequalities of multiparty entanglement in arbitrary-dimensional quantum systems. We further show that o

We establish a characterization of multi-qubit entanglement constraints in terms of non-negative power of entanglement measures based on unified-(q, s) entropy. Using the Hamming weight of the binary vector related with the distribution of subsystems, we establish a class of tight monogamy inequalities of multi-qubit entanglement based on the αth-power of unified-(q, s) entanglement for α ≥ 1. For 0 ≤ β ≤ 1, we establish a class of tight polygamy inequalities of multi-qubit entanglement in terms

I establish a unified view of polygamy of multiqubit entanglement. I first introduce a two-parameter generalization of the entanglement of assistance, namely, the unified entanglement of assistance for bipartite quantum states, and provide an analytic lower bound in two-qubit systems. I show a broad class of polygamy inequalities of multiqubit entanglement in terms of the unified entanglement of assistance that encapsulates all known multiqubit polygamy inequalities as special cases. I further s

We provide evidence for the validity of strong monogamy inequality of multiparty quantum entanglement using the square of convex-roof extended negativity (SCREN). We first consider a large class of multiqudit mixed states that are in a partially coherent superposition of a generalized $W$-class state and the vacuum, and provide some useful properties about this class of states. We show that monogamy inequality of multiqudit entanglement in terms of SCREN holds for this class of states. We furthe

We provide strong evidence for the strong monogamy inequality of multiqubit entanglement recently proposed [B. Regula et al., Phys. Rev. Lett. 113, 110501 (2014)]. We consider a large class of multiqubit generalized $W$-class states and analytically show that the strong monogamy inequality of multiqubit entanglement is saturated by this class of states.

We show that bipartite entanglement distribution (or entanglement of assistance) in multipartite quantum systems is by nature polygamous. We first provide an analytical upper bound for the concurrence of assistance in bipartite quantum systems and derive a polygamy inequality of multipartite entanglement in arbitrary-dimensional quantum systems.

Nonlocality without entanglement(NLWE) is a nonlocal phenomenon that occurs in quantum state discrimination of multipartite separable states. In the discrimination of orthogonal separable states, the term NLWE is used when the quantum states cannot be discriminated perfectly by local operations and classical communication. In this case, the occurrence of NLWE is independent of nonzero prior probabilities of quantum states being prepared. Recently, it has been found that the occurrence of NLWE ca