All Questions
Tagged with quantum-entanglement hilbert-space
163
questions
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
4
votes
1
answer
443
views
How can a basis change make a state suddenly separable?
I am working through my quantum optics textbook by Grynberg, Aspect and Fabre, and this concept has tripped me up a little.
(13) is an inseparable state, whereas (15) IS separable - but they are the ...
- 149
1
vote
3
answers
413
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Can a two-qubit state be unentangled via unitary operations?
There is an operator that takes a state for example of the type
$$|\psi \rangle=\frac{1}{\sqrt2}( |0\rangle | 1\rangle+|1\rangle | 0\rangle)$$
Into a not entangled type,and i guess that for unitary ...
user324481
0
votes
2
answers
46
views
What is the dimension of two quantum systems with bases $\{a_1,a_2\}$ and $\{b_1,b_2,b_3\}$, combined? [closed]
Quantum system A has a basis $\{a_1, a_2\}$. System B has a basis $\{b_1, b_2, b_3\}$. A and B evolve according to their own Hamiltonian and do not interact at all. If I consider A and B as one large ...
- 843
31
votes
7
answers
7k
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What is the actual use of Hilbert spaces in quantum mechanics?
I'm slowly learning the quirks of quantum mechanics. One thing tripping me up is... while (I think) I grasp the concept, most texts and sources speak of how Hilbert spaces/linear algebra are so useful ...
- 531
2
votes
1
answer
104
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Entanglement and continuous basis sets
I've usually seen entanglement discussed when dealing with discrete basis sets. For example, if we consider the Hilbert space $\mathcal{H}_0\otimes\mathcal{H}_1$, where both $\mathcal{H}_j$ are two ...
- 1,290
-1
votes
1
answer
150
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Fidelity for initial state
fidelity for pure state with respect to t=0 is 1. My teacher told me this.
But I am not getting this.
This is my detailed question
the initial state(t=0)$|\psi\rangle=|\alpha\rangle|0\rangle$
the ...
- 123
2
votes
1
answer
83
views
Does fidelity change with respect to time?
I have a fidelity
$$e^{-|\alpha|^2}e^{-|\alpha\sin(t)|^2}e^{-|\alpha\cos(t)|^2}$$
where $\alpha$ (coherent state) is$\sqrt{5}$.
I plotted fidelity against time in a graph.
For $t=0$, I got $ F= 4.5\...
- 123
1
vote
0
answers
132
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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
1
vote
1
answer
119
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Constructing orthonormal bases in sub-Hilbert spaces of $L^2(\mathbb R)$ defined for particular spatial regions?
I've explored the entanglement of modes by expanding the ground-state solution of a many-body problem as an infinite sum of Slater determinants of one-particle Hermite functions. The one-particle ...
1
vote
1
answer
207
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Will the Hilbert space get expanded when measuring the entangled state?
If I have two electrons that are indistinguishable, as I understand, they are entangled. And the Hilbert space that describes the behavior of this pair of electrons is a subspace of the Tensor product ...
- 47
0
votes
1
answer
221
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How to take partial inner product between tensor product states and GHZ state?
I am trying to solve some problems in which 3 people (Alice, Bob and Charlie) share 3 photons entangled in the state $|GHZ\rangle$ and Alice and Bob perform some joint measurement on $|GHZ\rangle$. I ...
- 103
2
votes
0
answers
85
views
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 ...
6
votes
2
answers
2k
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What are the relations between mixed/pure and separable/entangled states?
I read this question which clarified the concepts of mixed/pure/separable/entangled states, but I can't see if one of "mixed/pure" implies one of "separable/entangled" and/or vice ...
- 5,931
1
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2
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206
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Does measuring an entangled pure state imply the result on the other subsystem?
From the definition of entanglement of pure states:
Let the first system be in state $|\psi\rangle_A$ and the second in $|\psi\rangle_B$ with eigenstates $a_n|a_n\rangle$ and $b_m|b_m\rangle$ ...
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