How to make a separable product state in a given sub-Hilbert space
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Consider a Hilbert space of dimension $d^2$ and bipartite entangled states therein. I would like to generate (numerically) a collection of separable pure states that all lie within a sub-space of the Hilbert space. The subspace has been specified by an orthonormal set of vectors which spans it, and none of the vectors in the spanning set is itself separable. For example, for a pair of qubits the total space is of dimension $4$ and a subspace could be of dimension 3 or 2 (don't worry about dimens
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How to make a separable product state in a given sub-Hilbert space
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Consider a Hilbert space of dimension
d
2
𝑑
2
and bipartite entangled states therein. I would like to generate (numerically) a collection of separable pure states that all lie within a sub-space of the Hilbert space. The subspace has been specified by an orthonormal set of vectors which spans it, and none of the vectors in the spanning set is itself separable. For example, for a pair of qubits the total space is of dimension
4
4
and a subspace could be of dimension 3 or 2 (don't worry about dimension
1
1
.)
The above is my main question. A couple of related issues are: can there be subspaces (of dimension above
1
1
) which contain no separable pure states at all? And if the answer to that is "yes" then is there a test for that property?
entanglementnumerical
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Andrew Steane
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