COMPLEMENTARITY OF ENTANGLEMENT AND INTERFERENCE

A complementarity relation is shown between the visibility of interference and bipartite entanglement in a two qubit interferometric system when the parameters of the quantum operation change for a given input state. The entanglement measure is a decreasing function of the visibility of interference. The implications for quantum computation are briefly discussed.

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Optimal two-particle entanglement by universal quantum processes

Quantum Information and Computation ◽

10.26421/qic1.3-3 ◽

2001 ◽

Vol 1 (3) ◽

pp. 33-51

Author(s):

G Alber ◽

A Delgado ◽

I Jex

Keyword(s):

Hilbert Spaces ◽

Parameter Family ◽

Entanglement Measure ◽

Input State ◽

Quantum Processes ◽

Single Exception ◽

Universal Quantum

Within the class of all possible universal (covariant) two-particle quantum processes in arbitrary dimensional Hilbert spaces those universal quantum processes are determined whose output states optimize the recently proposed entanglement measure of Vidal and Werner. It is demonstrated that these optimal entanglement processes belong to a one-parameter family of universal entanglement processes whose output states do not contain any separable components. It is shown that these optimal universal entanglement processes generate antisymmetric output states and, with the single exception of qubit systems, they preserve information about the initial input state.

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Bipartite entanglement measure based on covariance

Physical Review A ◽

10.1103/physreva.75.062317 ◽

2007 ◽

Vol 75 (6) ◽

Cited By ~ 8

Author(s):

Isabel Sainz Abascal ◽

Gunnar Björk

Keyword(s):

Entanglement Measure ◽

Bipartite Entanglement

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Continuous variable controlled quantum dialogue and secure multiparty quantum computation

International Journal of Quantum Information ◽

10.1142/s0219749920500094 ◽

2020 ◽

Vol 18 (04) ◽

pp. 2050009 ◽

Cited By ~ 2

Author(s):

Ashwin Saxena ◽

Kishore Thapliyal ◽

Anirban Pathak

Keyword(s):

Quantum Computation ◽

Information Leakage ◽

Continuous Variable ◽

Quantum Dialogue ◽

Multiparty Computation ◽

Quantum Private Comparison ◽

Discrete Variable ◽

Bipartite Entanglement ◽

Present Scheme ◽

Private Comparison

A continuous variable (CV) controlled quantum dialogue (QD) scheme is proposed. The scheme is further modified to obtain two other protocols of (CV) secure multiparty computation. The first one of these protocols provides a solution of two-party socialist millionaire problem, while the second protocol provides a solution for a special type of multi-party socialist millionaire problem which can be viewed as a protocol for multiparty quantum private comparison. It is shown that the proposed scheme of (CV) controlled (QD) can be performed using bipartite entanglement and can be reduced to obtain several other two- and three-party cryptographic schemes in the limiting cases. The security of the proposed scheme and its advantage over corresponding discrete variable (DV) counterpart are also discussed. Specifically, the ignorance of an eavesdropper, i.e., information encoded by Alice/Bob, in the proposed scheme is shown to be more than that in the corresponding (DV) scheme, and thus the present scheme is less prone to information leakage inherent with the (DV) (QD) based schemes. It is further established that the proposed scheme can be viewed as a (CV) counterpart of quantum cryptographic switch which allows a supervisor to control the information transferred between the two legitimate parties to a continuously varying degree.

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Unified Monogamy Relations of Multipartite Entanglement

Scientific Reports ◽

10.1038/s41598-019-52817-y ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Awais Khan ◽

Junaid ur Rehman ◽

Kehao Wang ◽

Hyundong Shin

Keyword(s):

Analytic Formula ◽

Entangled States ◽

Multipartite Entanglement ◽

Entanglement Measure ◽

Mixed States ◽

Bipartite Entanglement ◽

Entanglement Of Formation ◽

Special Cases ◽

Qubit States ◽

Monogamy Relations

Abstract Unified-(q, s) entanglement $$({{\mathscr{U}}}_{q,s})$$ ( U q , s ) is a generalized bipartite entanglement measure, which encompasses Tsallis-q entanglement, Rényi-q entanglement, and entanglement of formation as its special cases. We first provide the extended (q; s) region of the generalized analytic formula of $${{\mathscr{U}}}_{q,s}$$ U q , s . Then, the monogamy relation based on the squared $${{\mathscr{U}}}_{q,s}$$ U q , s for arbitrary multiqubit mixed states is proved. The monogamy relation proved in this paper enables us to construct an entanglement indicator that can be utilized to identify all genuine multiqubit entangled states even the cases where three tangle of concurrence loses its efficiency. It is shown that this monogamy relation also holds true for the generalized W-class state. The αth power $${{\mathscr{U}}}_{q,s}$$ U q , s based general monogamy and polygamy inequalities are established for tripartite qubit states.

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Trade-off relations for operation entropy of complementary quantum channels

International Journal of Quantum Information ◽

10.1142/s0219749919500461 ◽

2019 ◽

Vol 17 (05) ◽

pp. 1950046

Author(s):

Jakub Czartowski ◽

Daniel Braun ◽

Karol Życzkowski

Keyword(s):

Quantum Channel ◽

Lower Boundary ◽

Von Neumann Entropy ◽

Input State ◽

Quantum Channels ◽

Quantum Operation ◽

Trade Off ◽

Von Neumann ◽

State Of The Environment ◽

Complementary Channel

The entropy of a quantum operation, defined as the von Neumann entropy of the corresponding Choi–Jamiołkowski state, characterizes the coupling of the principal system with the environment. For any quantum channel acting on a state of a given size, one defines the complementary channel, which sends the input state into the state of the environment after the operation. Making use of subadditivity of entropy, we show that for any dimension the sum of both entropies is bounded from below. This result characterizes the trade-off between the information on the initial quantum state accessible to the principal system and the information leaking to the environment. For one qubit maps we describe the interpolating family of depolarizing maps, for which the sum of both entropies gives the lower boundary of the region allowed in the space spanned by both entropies.

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