# All Questions

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### Am I doing anything wrong when trying to calculate the expectation value in Qiskit on the real hardware?

I am trying to use the method of calculating the expectation values of Pauli operators in Qiskit which I found here. However, the results obtained via IBMQ sampling differ significantly from the exact ...
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### What is the representative matrix for a measurement in the Bell-state basis?

I have a few questions about measurement in Bell-state basis. In particular, if $Z = \begin{bmatrix} 1 & 0\\ 0 & -1 \end{bmatrix}$ is for a measurement on the computational basis, then what ...
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### What extra functionality is available to an IBM Q Network member over a regular IBM Q Experience user

I've been trying to figure out the extra functionality available to IBM Q Network members that are not available to normal ...
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### How can I represent mixed states in Q#?

I have a mixed state with a density matrices corresponding to $\rho=\sum_0^{2^n-1}p_i|i\rangle\langle i|$. How would i represent this in Q#? How would I go about applying Unitary Operations $U$ on ...
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### How to measure the sign of quantum amplitudes

I have a quantum state on $n$ qubits ($2^n$ amplitudes) for which I know the amplitudes are real numbers. I want to take the state out as a vector. I can estimate the magnitude of the amplitudes ...
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### How can a half-wave plate affect the position qubit and not the polarization qubit of a photon?

I recently was watching these 2 videos on Coursera which show how to build a simple quantum computer that can implement the simplest case of the Deutsch-Jozsa algorithm (which uses only 2 qubits). ...