Top new questions this week: |
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Base codes with transversal non-Clifford - why not?A leading approach to circumventing the Eastin-Knill theorem involves using stabilizer codes which support a transversal implementation of the full Clifford group, and obtaining universal gateset via ...
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stim: why would order of CNOT operations affect detectorsI have two circuits (below) : first works fine (no complaints from stim); second comes back with a "non-deterministic detector" error. The difference between the two circuits is that the ...
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Why is the fastest quantum time complexity of unstructured search O(sqrt(n))?Recently, I have watched video on 3Blue1Brown about Grover's algorithm. He give an example that: To find a secret number in the range from 0 to n−1, you can query a hidden function that returns “true”...
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Greatest hits from previous weeks: |
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How does bra-ket notation work?Quantum algorithms frequently use bra-ket notation in their description. What do all of these brackets and vertical lines mean? For example: $|ψ⟩=α|0⟩+β|1⟩$ While this is arguably a question about ...
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Error: cannot import name 'BaseBackend' from 'qiskit.providers'when I try to use a quantum instance I get the error below. I'm using qiskit 0.37.0 and qiskit-aqua 0.9.5. Any hint suggested? Thanks in advance ...
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Density matrices for pure states and mixed statesWhat is the motivation behind density matrices? And, what is the difference between the density matrices of pure states and density matrices of mixed states? This is a self-answered sequel to What&#...
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Why does a Hamiltonian have to be Hermitian?Starting from: $$ -i\hbar \frac{d|\psi⟩}{dt} = H|\psi⟩ $$ I was able to do some working to prove that $U$ in the corresponding discrete representation $$ U(t_1,t_2) = exp\frac{-iH(t_2-t_1)}{\hbar} $...
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Are there emulators for quantum computers?Is there any way to emulate a quantum computer in my normal computer, so that I will be able to test and try quantum programming languages (such as Q#)? I mean something that I can really test my ...
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CNOT expressed with CZ and H gates by taking into account HZH =XFrom this link: Where equation 1 is: I can probably brute-force this by explicitly calculating this quantum circuit's effective 4x4 matrix and seeing that its equivalent to this teleportation ...
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What is the difference between a relative phase and a global phase? In particular, what is a phase?I know that $re^{i\theta} = x + iy$ for any complex number $x + iy$ by Euler's formula. How do you calculate relative and global phase?
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