All Questions
Tagged with algorithms quantum-information
31
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Is Quantum State Tomography (QST) an inherently supervised or unsupervised problem in Machine Learning?
I am studying how to apply neural networks to the problem of Quantum State Tomography (QST) and I got confused when it comes to decide if this is a supervised or unsupervised learning problem.
At ...
- 161
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34
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Algorithm that checks if a subspace of states contains a product state
Suppose I have two identical qudits, the full Hilbert space is $\mathcal{H}=(\mathbb{C}^{d})^{\otimes 2}$. Say I'm given a supspace of states $\Lambda\subset \mathcal{H}$. What is the fastest ...
- 883
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How Do Quantum Computers Work, Like Really [closed]
I understand in plain terms superposition and entanglement, but I'm very unclear how either of these could work as a means to increase computation power.
A helpful metaphor is that of the maze. A ...
- 129
1
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1
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336
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Number of qubits required in Shor's algorithm
People say that the number of qubits required in Shor's algorithm for factorizing $N$ should be
$2\log N$ for control register and $\log N$ for target register.
What is the reason why these numbers of ...
- 185
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140
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Is there a comparison table for quantum algorithms like VQE, QPE, QAOA, and so on?
I have one question: Recently, I studied about several algorithms like VQE, QPE, QAOA and so on. I would like to make some comparison tables about those algorithms, their strengths and weaknesses. If ...
5
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2
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361
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Is the universe's Kolmogorov complexity growing over time?
The Kolmogorov complexity of a deterministic universe is constant.
The Kolmogorov complexity of a nondeterministic universe grows over time. It grows whenever something happens that is not ...
- 129
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1
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746
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Bell State Measurement Algorithm
I'm relatively new to quantum computation and am taking a course in it. I was wondering if it is possible to code an algorithm which would be able to take an input of a 2 qubit state and perform a ...
- 21
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460
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Is the only difference between tDMRG and TEBD the way the central sites are shifted?
I have been reading up on time evolution methods using matrix product states. Reading from Schollwoeck's notes on the density matrix renormalization group, (https://arxiv.org/abs/1008.3477), I looked ...
- 141
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2
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290
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Shor's algorithm with adversary - can (delayed) erasure of value qubits cripple calculations?
Let's look at quantum subroutine of Shor's algorithm:
Hadamard gates create superposition of all (exponential number) values for input qubits.
Then we perform a classical function on them, which is ...
- 960
9
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2
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Shor's algorithm - why doesn't the final collapse of the auxiliary qubits cripple the computation?
Let's look at quantum subroutine of Shor's algorithm (image source):
Hadamard gates create superposition of all (exponential number) values for input qubits.
Then we perform a classical function ...
- 960
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1
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101
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What does "given one application of a black box" mean, in a quantum-computing context?
From Kaye, Laflamme and Mosca's An Introduction to Quantum Computing:
Exercise 7.1.1 (Bernstein-Vazirani problem) Show how to find $\mathbf a \in Z_2^n$ given one application of a black box that maps ...
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230
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Shor's algorithm - its causality and similar exploitation of QM?
Shor's algorithm is rather the most interesting quantum algorithm as it shifts a problem which is believed to need exponential classical time, to polynomial time for quantum computer, additionally ...
- 960
2
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3
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386
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Where is a classical computer better than a quantum one? [closed]
Where is a classical computer better than a quantum computer? Is there any known domain where classical algorithms always beat quantum ones, say, both in terms of time and space complexity?
If yes,...
- 168
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197
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Assumptions in the proofs for the optimality of Grover's Search Algorithm
I was trying to understand this paper in which it is proved that Grover's search algorithm is optimal.
On page 4, beginning of section 2 of the paper the author says the following
In the proof I ...
- 3,905
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Using quantum state tomography in quantum search algorithms
Problem statement: The search space A involves elements $|0\rangle $, $|2\rangle$... $|d-1\rangle$. An oracle is provided for the function $f(x)$ where
\begin{align}
f(x)&=1 \quad x=x^{'}\in A \\
...
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