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1500 questions
7
votes
1 answer
When you act on a multi-qubit system with a 2-qubit gate, what happens to the third qubit?
I am learning to manipulate Qbits and recently I saw the teleportation algorithm. I read about it in two places: Wikipedia and Lecture Notes from Ronald de Wolf (Page 7, 1.5 Example: Quantum Teleportation).
I'd like to understand how to operate with…
Marcelo Fornet
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7
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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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7
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3 answers
How are IBM's 127 qubits more potent than the 5760 qubits D-Wave - Advantage_system6.1?
Hi I'm a newbie in quantum computing recently I had a look at the AWS braket and I've seen they had a machine called D-Wave - Advantage_system6.1 that has 5760 qubits but when I googled the highest qubits quantum computer so far it showed me IBM's…
Zakaria Halloumi
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7
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1 answer
Why does code switching not allow for universal fault-tolerant quantum computation?
In this paper, the authors briefly mention that one proposed method to bypass the Eastin-Knill theorem is to perform code-switching. That is, given codes $C_1$ and $C_2$ which permit a complementary set of transversal gates, one can encode their…
SescoMath
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Rotation resolutions in operations for qubits in commercial implementations
I have found information about Honeywell provider supporting operations with high-resolution rotations (i.e. around $\pi/500$) here.
What are typical maximal rotation resolution values supported by existing implementations and what is their…
Mariusz
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Five qubits can be entangled in how many ways?
It is well-known that there are two ways to entangle three qubits (https://arxiv.org/abs/quant-ph/0005115) and nine ways to entangle four qubits (https://arxiv.org/abs/quant-ph/0109033).
I found in a paper (page 22 left column of…
R.G.J
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7
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1 answer
Has anyone analyzed multi-round nonlocal games?
The traditional definition of a nonlocal game is restricted to having two players and one round (e.g., here), but it is natural to consider a more general class of games that may have more than two players and more than one round of questions. While…
Evan Jenkins
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7
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Are there separable states $\rho$ with separable pure decompositions requiring $\operatorname{rank}(\rho)^2$ components?
In What separable $\rho$ only admit separable pure decompositions with more than $\mathrm{rank}(\rho)$ terms?, examples were given of separable states $\rho$ with separable decompositions requiring more than $\operatorname{rank}(\rho)$ components.…
glS
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7
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2 answers
Chronology of discovery of quantum phase estimation algorithm
I'm a bit confused about exactly when the phase estimation algorithm was discovered. The Wiki article, as well as various textbooks and papers, says that it was introduced in 1995 by Alexei Kitaev, but Shor's algorithm, which uses phase estimation,…
tomdodd4598
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7
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Origin of braiding in measurement-only TQC
I have a technical question on the "measurement-only"-proposal for topological quantum computation on anyons. First some background:
Background.
While it has become a common idea that topological quantum gates could be implemented by braiding…
Urs Schreiber
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7
votes
1 answer
Why am I able to simulate such high qubit numbers on my laptop?
Recently I've been working on a VQE-related project, for which I'm using Qiskit's TwoLocal variational form (qiskit version 0.34.2). I noticed that I was able to simulate this circuit up to surprisingly high qubit numbers on my laptop, so I wanted…
Matthias
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7
votes
1 answer
Is the Clifford group a semidirect product?
This is from
Is the Clifford group finite?
"Define the Clifford group $ \mathrm{Cl}_n(p) $ of n qudits of prime dimension p as the unitary normaliser of the generalised Pauli group.
Define the projective group…
Ian Gershon Teixeira
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7
votes
3 answers
How do you send an array of qubits to an operation in Q#?
I have the following operation in my .qs files:
operation myOp(qubits: Qubit[]) : () {
// uses elements from the qubit array
}
How do I send an array of qubits to this in the driver file?
The following did not work:
Qubit[] qubits =…
Mahathi Vempati
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7
votes
2 answers
From Q# measurements to Bloch sphere
I would like to represent the state of a qubit on a Bloch sphere from the measurements made with Q#.
According the documentation, it is possible to measure a qubit in the different Pauli bases (PauliX, PauliY, PauliZ). This returns Zero if the +1…
JRial95
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7
votes
1 answer
How to benchmark a quantum computer?
Using a simple puzzle game to benchmark quantum computers is the most clever approach I have seen so far.
The author of the aforementioned article, James, makes a nice analogy to buying a laptop ("more than just a single number when comparing") in…
user820789
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