All Questions
Tagged with quantum-entanglement hilbert-space
29
questions with no upvoted or accepted answers
5
votes
1
answer
133
views
How to measure the entanglement of three entangled qubits?
The entanglement of two qubits is calculated using "concurrence" and "negativity". Concurrence and negativity, however, are only used for "two" entangled qubits. Is there ...
- 89
3
votes
0
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85
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Constructing wavefunction for a mixed state
This question is somehow the reverse of another question.
If a quantum system $S$ is in a pure state, then we can find a wavefunction that describes $S$. This wavefunction is unique up to a phase ...
- 1,440
3
votes
0
answers
212
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Confusion about the tensor product structure of a multi-fermion Hilbert space
I often see people study entanglement in fermionic systems. The setup is often like this. Suppose we have a 1d lattice of $2L $ sites, which is divided into a left part and a right part, each with $L ...
- 1,957
2
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0
answers
92
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Computing Fubini-Study expectation values over $\mathbb{C}P^n$
In finite-dimensional textbook quantum mechanics, we postulate that states of our system are rays in a Hilbert space $\mathcal{H}$ with dimension $\dim{\mathcal{H}} = n+1$ where $n \in \mathbb{N}$, ...
- 2,676
2
votes
0
answers
39
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A Hamiltonian acts simply on each state in some subspace. Can it be identified with a single simple operator on the subspace?
This is a simplified version of a recent question I asked. My hope is that this simplified version will be easier to tackle. The motivation behind both of these questions is roughly to ask "Given ...
- 2,292
2
votes
1
answer
137
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Does spin entanglement imply position entanglement?
My question is whether two electrons can be entangled only with respect to their spins but not with respect to some other observable, such as position.
I initially believed that spin-entanglement ...
- 1,073
2
votes
0
answers
85
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Does nuclearity in a rigged Hilbert space have something to do with entanglement?
For extending the Dirac notation to the continuous spectrum we need to introduce a rigged Hilbert space $(\mathcal S,\mathcal H,\mathcal S')$ where $\mathcal S$ must have some particular properties in ...
2
votes
0
answers
68
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Wave function collapse for experimental quantum state preparation
Has the John von Neumann projection, or the wave function collapse, been used in the experimental preparation of quantum states? As an illustration, for a pair of EPR-type entangled 2-level atoms
$$|\...
- 346
1
vote
0
answers
46
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What happens when a maximally entangled state passes through a $k$-extendible channel?
In the context of Phys. Rev. A 104, 022401 (arXiv:1803.10710), Figure 3
What happens when a maximally entangled state( not $k$ extendible even for $k=2$) passes through a $k$-extendible channel? We ...
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1
vote
0
answers
55
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Is the set of $k$-extendible states compact?
Let 𝑘 ∈ ℕ
. A state 𝜌_𝐴𝐵 on a bipartite Hilbert space A ⊗ B
is 𝑘-extendible with respect to B if there exists a state 𝜌_(𝐴𝐵_𝑘)
on A ⊗ B^(⊗𝑘), which is invariant under any permutation of the ...
- 11
1
vote
0
answers
72
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Could Dark Matter be comprised of gravitational waves entrained in the bulk?
The evidence is strong that more massive galaxies have more massive Dark Matter (DM) halos (for example, Qi Guo et al, Monthly Notices of the Royal Astronomical Society, Vol 404 (2010)). Might this ...
- 11
1
vote
0
answers
44
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Representation of $d$-dim maximally mixed state in different bases
Consider the maximally entangled state in $d$ dimensions, $|\Psi\rangle:= \frac{1}{\sqrt{d}} \sum_{i=0}^{d-1} |i,i\rangle^{AB}$, where $|i\rangle^{AB} := |i\rangle^{A}\otimes|i\rangle^{B}$ and $\{|i\...
- 525
1
vote
0
answers
127
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Is the NOON state entangled even if $N=1$?
Let $\mathcal{H}\cong\mathbb{C}^2$ be the Hilbert space of states of a single particle. Let $\{|\psi_A\rangle, \psi_B\rangle\}$ be a basis for $\mathcal{H}$. I now want to describe an ensemble of ...
- 11
1
vote
0
answers
67
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Two questions about tensor products
I didn't take a linear algebra class in undergrad, but have picked up a fair bit by osmosis when learning QM. I'm hoping someone can help me to understand a particular topic -- namely tensor products.
...
- 325
1
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0
answers
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First order logic of complex quantum theory
Suppose we describe quantum theory through the København interpretation, that is, through unitary linear algebra of complex Hilbert spaces.
Can quantum theory in this description (the part that ...
- 355