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1500 questions
8
votes
1 answer
Are Absolutely Maximally Entangled states maximally entangled under all entanglement monotones?
In Ref. [1] absolutely maximally entangled (AME) states are defined as:
An $\textrm{AME}(n,d)$ state (absolutely maximally entangled state) of $n$ qudits of dimension $d$, $|\psi\rangle \in \mathbb{C}^{\otimes n}_d$, is a pure state for which every…
SLesslyTall
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What is the complexity of hidden subgroup problems?
It is often stated that some of the "hidden subgroup problems" can be efficiently solved by quantum computers if the group is abelian, while no efficient algorithm is known for the non-abelian case. The problems of the first case include…
Doriano Brogioli
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Why do we need to keep of history of $d$ cycle for surface code in order to resist against data *and* measurement errors
I am trying to understand why we need to keep in memory $d$ clock cycles in order to correct efficiently for the surface code where the syndrome qubits are also faulty ($d$ is the code distance).
[edit]: It seems that there is no real "proof" of…
Marco Fellous-Asiani
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Qubit fidelity of DWAVE device
Since DWAVE quantum device is constructed using superconducting flux qubits, each qubit cannot be produced identically so that the fidelity of the qubit must be different. DWAVE only provides the information of their devices in terms of number of…
peachnuts
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Quantum algorithm for linear systems of equations (HHL09): Step 1 - Number of qubits needed
This is a continuation of Quantum algorithm for linear systems of equations (HHL09): Step 1 - Confusion regarding the usage of phase estimation algorithm
Questions (contd.):
Part 2: I'm not exactly sure how many qubits will be needed for the Step 1…
Sanchayan Dutta
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8
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How to find the stabilizer generators for a post-measurement state?
My question is closely related to this one.
A bit of vocabulary and a reminder of basic properties:
I consider the total Hilbert space of the problem has dimension $2^n$.
I call a "well defined family of generators" a family of $n$-Pauli matrices…
Marco Fellous-Asiani
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8
votes
2 answers
How could a quantum network be constructed to handle 10,000 clients concurrently?
The C10k Problem is a classical computing problem whose name (C10k) is a numeronym for concurrently handling ten thousand connections.
How could a quantum network be constructed to handle 10,000 clients concurrently?
user820789
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Changing indices of qubits in QISKit
I was wondering if something like this is possible in QISKit: let's say we have two registers containing target and ancilla qubits:
$a_0$ -------------------
$a_1$--------------------
$\vdots$
$a_4$ ------------------
$t_0$ ------------------
$t_1$…
brzepkowski
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4 answers
Simulating a quantum circuit with decoherence and noise
Based on the answers given here and here, it is pretty clear that an arbitrary quantum circuit can be simulated with matrix algebra. The difficulty is that this assume perfect fidelity. I am unsure how to generalize this method to take into account…
Anna Naden
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Are Genetic Programming runtimes faster on QCs than on classical computers?
If this isn't known, would they theoretically be? I'm particularly interested in knowing whether a QC would be faster at evaluating the fitness function of the possible solutions than a classical machine
amwintermute
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What does "conjugation of coordinates" mean with respect to GF(4) (quantum) codes
In On the classification of all self-dual additive codes over $\textrm{GF}(4)$ of length up to 12 by Danielsen and Parker, they state:
Two self-dual additive codes over $\textrm{GF}(4)$, $C$ and $C^\prime$, are equivalent if and only if the…
SLesslyTall
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1 answer
How to apply single and two qubit gates to 2 qubits multiple times?
Let's say we have the following quantum circuit:
Let's say we input the state $|00\rangle$ . Both of the $H$ gates produce the output $1/\sqrt{2}$, but which one of the following $2$ vectors is the input of $\operatorname{CNOT}$ gate:
$1:…
PiMan
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2 answers
Practical Implementations of QECCs in IBM Q Experience
I am learning how to program the IBM Q Experience quantum computers in order to learn more about how does it work and in order to perform some experiments in it. By doing so I was wondering what are the most advanced things that have been done in…
Josu Etxezarreta Martinez
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What's the difference between a set of qubits and a capacitor with a subdivided plate?
This is probably just a misunderstanding on my part, but everything I've seen on what quantum computers do thus far seems to suggest that the actual process of reading the entangled qubits would be equivalent to reading the value of a plate opposing…
CoryG
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Simon's algorithm: Number of equations
During the classical pre-processing stage of Simon's algorithm, we repeat the quantum operations $n-1$ times to get
$$
\begin{alignat}{7}
y_{1} \cdot s & \phantom{\vdots} =~ && 0 \\ y_{2} \cdot s & \phantom{\vdots}=~ && 0 \\ & \phantom{=} \vdots \\…
BlackHat18
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