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3 answers
References examining Bell inequality violations at large distances
Could anyone point to some references examining Bell inequality violations at large distances please?
I see many times, in pop science articles and research literature alike, that the quantum information of the entangled state is transmitted…
psitae
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7
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Are SIC-POVMs optimal for quantum state reconstruction?
Mutually unbiased bases (MUBs) are pairs of orthonormal bases $\{u_j\}_j,\{v_j\}_j\in\mathbb C^N$ such that
$$|\langle u_j,v_k\rangle|= \frac{1}{\sqrt N},$$
for all $j,k=1,...,N$.
These are useful for a variety of reasons, e.g. because they provide…
glS
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7
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Resources for QRAM implemented as a subroutine for quantum algorithm
I am currently working on a project on a higher version of amplitude amplification and for that we want to store the initial state (which will be some sort of superposition) into a QRAM. Now we want to simulate the working of the algorithm and I am…
Parmeet Singh EP 066
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7
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1 answer
Oblivious Amplitude Amplification & Eigenstate decomposition
Looking at the oblivious AA (OAA) : https://docs.microsoft.com/en-us/azure/quantum/user-guide/libraries/standard/algorithms
I am trying to figure out the eigendecomposition of Q, which leads to below. Any help or suggestion on how to derive these…
John Parker
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7
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1 answer
Are projective measurements the only optimal measurements to discriminate between two states?
Consider two density matrices $\rho$ and $\sigma$. The task is to distinguish between these two states, given one of them --- you do not know beforehand which one.
There is an optimal measurement to distinguish between these two states --- the…
BlackHat18
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7
votes
1 answer
Implement the classical shadow coding error?
I'm trying to reproduce the basic method of classical shadow, which is based on the tutorial of pennylane. However, I've met some realization problems here when I finish reading the tutorial of pennylane, and trying to finish the method myself, just…
narip
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7
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1 answer
Definition of magic $T$ and $H$ states: are there different definitions for them?
I am a bit confused by the definition of magic $T$ and $H$ states and I would like to check if their name is actually not uniformly spread in the literature (or if I am not understanding something).
In the original paper about them, they are defined…
Marco Fellous-Asiani
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7
votes
2 answers
ZX-calculus: pi-copy rule not required for completeness?
In ZX-calculus, the $\pi$-copy rule is quite famous, and is used for instance here:
However, this paper never introduces this rule, and says that this set is enough to prove the Clifford completeness of the ZX calculus:
Is it just that they forgot…
Léo Colisson
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1 answer
How to avoid error when applying certain combinations of degree of freedom rotations using a quantum circuit?
When applying each of the six degree of freedom rotations (or certain combinations of them) in an SO(4) using quantum gates, the results I expected are produced. For example, the following circuit in Craig Gidney's Quirk tool demonstrates rotations…
JavaFXpert
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7
votes
2 answers
Why are Bell states the maximally entangled ones?
I just want to know why actually Bell states are examples of maximally entangled states and significance of that "maximal" term. Is there anything for proving that?
user18115
7
votes
1 answer
BHT algorithm implementation
Summary of Method
Amplitude Amplification Summary
The BHT algorithm uses amplitude amplification, a nice generalisation of Grover's algorithm, where there is a subset $G\subset X$ of good elements in the orthonormal basis $X$. Below is a brief…
Chris Long
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7
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1 answer
Are anti-unitary gates possible?
According to Wigner’s theorem, every symmetry operation must be represented in quantum mechanics by an unitary or an anti-unitary operator. To see this, we can see that given any two states $|\psi\rangle$ and $|\psi'\rangle$, you would like to…
Mauricio
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7
votes
1 answer
Elementary question: is $\langle a|b \rangle$ the same as $\langle a||b\rangle$?
In trying to learn more about quantum computing, one of the first things encountered is a definition of the inner product $\langle a|b\rangle$. If I interpret it correctly, and looking near the bottom of page 15 of the 2011 book by Rieffel and…
mhucka
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Why does job.running in QISKit output False, even if the job is still running?
I submitted a job in the 0.5.0 version of QISKit using
job = execute(qc, 'ibmqx5', shots=shots)
This just submits the job, and does not wait for a result.
I then immediately tested whether the job was still running using
print(job.running)
This…
James Wootton
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7
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1 answer
Translation of color/toric code to a small network of solid-state spins
Within Quantum Error Correction and stabilizer codes, toric codes/surface codes are very tempting, mainly for their high error threshold. For more background please check up, in our Physics sister (aunt?) site: Quantum Error Correction: Surface code…
agaitaarino
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