I try to immagine the hadamard gate on a bloch sphere and it is obvious that it is the sum of the pauli $x$ and $z$ gate matrices.So that means we rotate the "vector" around the x axe and ...

I am working with an $N \times N$ matrix $A$ whose columns are computational basis vectors:$$A = [e_{i_0}, e_{i_1}, \dots, e_{i_{N-1}} ] = \sum_{j=0}^{N-1} |i_j\rangle \langle j|,$$where each $i_j ...

I 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 ...

I've developed a novel quantum random number generator protocol featuring:· Forward secrecy via quantum ratcheting· Bell-test certified randomness· 300x throughput vs current quantum RNG· Compact ...

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 ahidden function that returns “true”...

Consider the following Stim circuit which is three rounds of a rotated surface code experiment initialized in the $\vert +\rangle$ logical state....

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 ...

I have noticed a lot of quantum algorithms that do not output an exact answer generally scale as $O(\log(1/\epsilon))$ where $\epsilon$ is the error threshold. I initially thought that this is because ...

We know the quantum circuit representation of Fourier operator. Now, I want the quantum circuit for the following unitary matrix using single and two qubit gates:$$U =\begin{pmatrix}F_3 & 0 \\...

Given a N qubits quantum register, in state $1/\sqrt{2}(|a\rangle+|b\rangle)$, my goal is to find sum of a and b (a+b) or subtraction (b-a).Taking classical example, let [7, 13], the discret FT will ...

The role of adding observables is not clear to me. Here are some points of confusion :(1)From the circuit I generate a detector error model using dem from which I generate twomatrices (pcm and lcm) ...

Sorry for the vague title, what I’m really asking is: when writing a compiler for a quantum DSL, many languages have chosen an imperative or functional host language. Few, if any, have chosen a purely ...

In a small open quantum system with a system qubit $S$ and an environment split into an accessible fragment $F$ and an inaccessible remainder $R$, consider the following situation.Two global ...

I am going through Ryan O'Donnell's quantum computing class homeworks, and on problem 6 of this assignment you are asked to prove $QMA$ in $PP$ using the fact that $RestartingPP = PP$, where $...

I am computing the 1-RDM of the H₂ molecule (STO-3G, 0.735 Å) using VQE in Qiskit + Qiskit Nature. A few months ago, when I ran the exact same code on the same laptop, the spin-summed 1-RDM always had ...