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1500 questions
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Is there an intuition built on ansatz in VQE algorithm or is it more a trial and error approach?
Variational Quantum Eigensolver is a popular algorithm in Quantum Computing. But the ansatz part is very tricky. I do not really understand if they are built on some intuition, according to hardware or something else; or if it was just a trial and…
cnada
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What is the complexity of modulo order-finding problem on classical computer?
It doesn't seem to be NP-complete. But has it been proved to be NP-hard?
user33260
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12
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Are there any known or obvious practical applications for good solutions to the optimal polynomial intersection problem?
I learned from Aaronson's blog about a recent preprint by Jordan, Shutty, Wootters, (our very own) Zalcman, Schmidhuber, King, Isakov, and Babbush that provides an efficient quantum algorithm to give good solutions to what they call the "optimal…
Mark Spinelli
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Quantum Algorithms for Convolution
I was looking into applications of Quantum Computing for machine learning and encountered the following pre-print from 2003. Quantum Convolution and Correlation Algorithms are Physically Impossible. The article doesn't appear to have been published…
DPL
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How can I calculate the inner product of two quantum registers of different sizes?
I found an algorithm that can compute the distance of two quantum states. It is based on a subroutine known as swap test (a fidelity estimator or inner product of two state, btw I don't understand what fidelity mean).
My question is about inner…
Aman
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1 answer
How are quantum algorithms devised?
This is a soft question, but I find it to be a very pertinent one...
Algorithms for Grover's search and Simon's problems seem to come completely out of the blue, and I find it very hard to understand what their thought process was when it came to…
Alan Whitteaker
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Can you give an intuitive idea behind how the Minimum Weight Perfect Matching (MWPM) decoder work?
The Minimum Weight Perfect Matching (MWPM) decoder seems to be the most popular choice for decoding error syndromes in Surface Code quantum error correction. Can anyone give an intuitive idea of how it works, with an example?
Aubrey Sharansky
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Why can't there be an error detecting code with fewer than 4 qubits?
Essentially this boils down to: Is it possible to encode a single logical qubit in three physical qubits so that the resulting code has distance two?
In other words, does a $[\![3,1,2]\!]$ code exist?
Comments:
No $[\![3,1,2]\!]$ stabilizer code…
Ian Gershon Teixeira
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Group theory lecture for quantum information
I am looking for a nice lecture about group theory for quantum information. Ideally a video lecture.
I know some of the very basics as I am familiar with the stabilizer formalism but there are many "important" things, for instance, representation…
Marco Fellous-Asiani
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Are all $[[n, k, d]]$ quantum codes equivalent to additive self-orthogonal $GF(4)^n$ classical codes?
Theorem 2 of [1] states:
Suppose $C$ is an additive self-orthogonal sub-code of $\textrm{GF}(4)^n$, containing $2^{n-k}$ vectors, such that there are no vectors of weight $
SLesslyTall
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What does it mean for a density matrix to "act on a Hilbert space $\mathcal{H}"$?
For a Hilbert space $\mathcal{H}_A$, I have seen the phrase
density matrices acting on $\mathcal{H}_A$
multiple times, e.g. here.
It is clear to me that if $\mathcal{H}_A$ has finite Hilbert dimension $n$, then this makes sense mathematically,…
Peter
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1 answer
Embedding classical information into norm of a quantum state
According to An introduction to quantum machine learning (Schuld, Sinayskiy & Petruccione, 2014), Seth Lloyd et al. say in their paper: Quantum algorithms for supervised and unsupervised machine learning that classical information can be encoded…
Sanchayan Dutta
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What does the paper "Training Variational Quantum Algorithms Is NP-Hard (Phys. Rev. Lett. 127, 120502)" mean?
I have seen the recent paper "Training Variational Quantum Algorithms Is NP-Hard (Phys. Rev. Lett. 127, 120502)" and the authors stated that training the classical optimization in variational quantum algorithms is NP-Hard.
Does it mean we cannot…
Chao-Hua Yu
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Where exactly does entanglement appear in Shor's algorithm?
One deals with the notion of superposition when studying Shor's algorithm, but how about entanglement? Where exactly does it appear in this particular circuit?
I assume it is not yet present in the initial state $\left|0\right>\left|0\right>$, but…
wondering
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When was the first use of the word Entanglement?
Schrödinger wrote a letter to Einstein after the 1935 EPR paper, and in that letter Schrödinger used the German word "Verschränkung" which translates into "entanglement", but when was the word first used in English?
Schrödinger's 1935 paper written…
user1271772 No more free time
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