1,773 research outputs found
Tighter weighted polygamy inequalities of multipartite entanglement in arbitrary-dimensional quantum systems
We investigate polygamy relations of multipartite entanglement in
arbitrary-dimensional quantum systems. By improving an inequality and using the
th () power of entanglement of assistance, we provide a
new class of weighted polygamy inequalities of multipartite entanglement in
arbitrary-dimensional quantum systems. We show that these new polygamy
relations are tighter than the ones given in [Phys. Rev. A 97, 042332 (2018)]
Ordering states with various coherence measures
Quantum coherence is one of the most significant theories in quantum physics.
Ordering states with various coherence measures is an intriguing task in
quantification theory of coherence. In this paper, we study this problem by use
of four important coherence measures -- the norm of coherence, the
relative entropy of coherence, the geometric measure of coherence and the
modified trace distance measure of coherence. We show that each pair of these
measures give a different ordering of qudit states when . However, for
single-qubit states, the norm of coherence and the geometric coherence
provide the same ordering. We also show that the relative entropy of coherence
and the geometric coherence give a different ordering for single-qubit states.
Then we partially answer the open question proposed in [Quantum Inf. Process.
15, 4189 (2016)] whether all the coherence measures give a different ordering
of states.Comment: 12 page
Amending coherence-breaking channels via unitary operations
The coherence-breaking channels play a significant role in quantum
information theory. We study the coherence-breaking channels and give a method
to amend the coherence-breaking channels by applying unitary operations. For
given incoherent channel , we give necessary and sufficient conditions
for the channel to be a coherence-breaking channel and amend it via unitary
operations. For qubit incoherent channels that are not
coherence-breaking ones, we consider the mapping and present
the conditions for coherence-breaking and channel amendment as well.Comment: 8 page
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