40,797 research outputs found
Multiparty Quantum Secret Sharing
Based on a quantum secure direct communication (QSDC) protocol [Phys. Rev.
A69(04)052319], we propose a -threshold scheme of multiparty quantum
secret sharing of classical messages (QSSCM) using only single photons. We take
advantage of this multiparty QSSCM scheme to establish a scheme of multiparty
secret sharing of quantum information (SSQI), in which only all quantum
information receivers collaborate can the original qubit be reconstructed. A
general idea is also proposed for constructing multiparty SSQI schemes from any
QSSCM scheme
All Multiparty Quantum States Can Be Made Monogamous
Monogamy of quantum correlation measures puts restrictions on the sharability
of quantum correlations in multiparty quantum states. Multiparty quantum states
can satisfy or violate monogamy relations with respect to given quantum
correlations. We show that all multiparty quantum states can be made monogamous
with respect to all measures. More precisely, given any quantum correlation
measure that is non-monogamic for a multiparty quantum state, it is always
possible to find a monotonically increasing function of the measure that is
monogamous for the same state. The statement holds for all quantum states,
whether pure or mixed, in all finite dimensions and for an arbitrary number of
parties. The monotonically increasing function of the quantum correlation
measure satisfies all the properties that is expected for quantum correlations
to follow. We illustrate the concepts by considering a thermodynamic measure of
quantum correlation, called the quantum work deficit.Comment: 6.5 pages, 2 figures, RevTeX 4-1, Title in the published version is
"Monotonically increasing functions of any quantum correlation can make all
multiparty states monogamous
Locally Accessible Information of Multisite Quantum Ensembles Violates Monogamy
Locally accessible information is a useful information-theoretic physical
quantity of an ensemble of multiparty quantum states. We find it has properties
akin to quantum as well as classical correlations of single multiparty quantum
states. It satisfies monotonicity under local quantum operations and classical
communication. However we show that it does not follow monogamy, an important
property usually satisfied by quantum correlations, and actually violates any
such relation to the maximal extent. Violation is obtained even for locally
indistinguishable, but globally orthogonal, multisite ensembles. The results
assert that while single multiparty quantum states are monogamous with respect
to their shared quantum correlations, ensembles of multiparty quantum states
may not be so. The results have potential implications for quantum
communication systems.Comment: 6 pages, RevTeX
Local implementation of nonlocal operations of block forms
We investigate the local implementation of nonlocal operations with the block
matrix form, and propose a protocol for any diagonal or offdiagonal block
operation. This method can be directly generalized to the two-party multiqubit
case and the multiparty case. Especially, in the multiparty cases, any diagonal
block operation can be locally implemented using the same resources as the
multiparty control-U operation discussed in Ref. [Eisert et al., Phys. Rev. A
62, 052317(2000)]. Although in the bipartite case, this kind of operations can
be transformed to control-U operation using local operations, these
transformations are impossible in the multiparty cases. We also compare the
local implementation of nonlocal block operations with the remote
implementation of local operations, and point out a relation between them.Comment: 7 pages, 3 figure
Non-additivity of quantum capacity for multiparty communication channels
We investigate multiparty communication scenarios where information is sent
from several sender to several receivers. We establish a relation between the
quantum capacity of multiparty communication channels and their distillability
properties which enables us to show that the quantum capacity of such channels
is not additive.Comment: 4 pages, 1 figur
- …