Questions tagged [entanglement-breaking-channels]
a class of stochastic maps, or channels, whose action (when tensored with the identity) on an entangled state always yields a separable state.
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How to write the joint action of a CP map that acts on a single qubit of a bipartite state?
The question
Say I have a completely-positive (CP) map $\mathcal{A}_{ij}$ defined in terms of two projectors $\Pi_i = |i\rangle \langle i |$ and $\Pi_j = |j\rangle \langle j |$ that acts on a density ...
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How can one check if a given quantum channel is unitary?
A unitary channel is a channel $\mathcal{U}$ of the following form:
$\mathcal{U}(\rho) = U\rho U^{\dagger}$.
A mixed unitary channel is a channel $\mathcal{U}_m$ of the form: $\mathcal{U}_m(\rho) = \...
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Are entanglement breaking channels of any use?
As the name suggests, an entanglement breaking channel $\Phi$ is such that $(Id \otimes \Phi)[\rho]$ is always separable, even when $\rho$ is entangled. Won't such channels be useless, as they destroy ...
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A way to check if entanglement is increased or decreased
I was wondering if there is a way to check if the amount of entanglement is increased or decreased after a quantum operation without calculating the actual value.
That is, it does not concern with the ...
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Why are entanglement breaking channels, defined as $\Phi(\rho)=\sum_a \operatorname{Tr}(\mu(a)\rho)\sigma_a$, entanglement breaking?
Define an entanglement breaking channel $\Phi$ as a channel (CPTP map) of the form
$$\Phi(\rho) = \sum_a \operatorname{Tr}(\mu(a)\rho) \sigma_a\tag A$$
for some POVM $\{\mu(a)\}_a$ and states $\...
glS♦
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