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Questions tagged [qubit-mapping]

For questions on the process of mapping virtual qubits to physical ones when transpiling a quantum circuit. For questions that are about mapping some quantity to a qubit representation, use the encoding tag.

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How to easily get the number of qubits required when using QAOA from qiskit_algrithms?

I would like to know if there is a easy way or native solution to retrieve the number of qubits that is required when using QAOA from qiskit_algorithms package to ...
0 votes
0 answers
22 views

Custom Mapping using up-to-date Machine Characteristics

I'm working to optimize mappings from virtual to hardware qubits using error and calibration data from the backend. I've implemented my algorithm. When I submit a job, it of course takes 1-5 hours to ...
1 vote
1 answer
474 views

What do arbitrary encoding circuits provide?

I'm about to implement my first VQC for image classification and I'm trying to figure out which data encoding method could fit better the problem. From what I've understood, there are three main ...
3 votes
2 answers
862 views

Copying |0⟩, |1⟩ Qubits will break the no-cloning theorem?

I am trying to create a bit string of |0⟩'s and |1⟩'s in order to create an array. Would this still break the no-cloning theorem since we do know their state: they are |0⟩'s and |1⟩'s. If possible, ...
1 vote
1 answer
187 views

Using machine learning to determine a good initial mapping for a quantum circuit

I am trying to use a machine learning model to find a good initial mapping for a quantum circuit. I am trying to minimise the number of swap operations i.e. the number of CNOT gates. This is my ...
1 vote
1 answer
572 views

Specifying Ancilla qubits for initial_layout parameter in qiskit.transpile

So I have an array which specifies the initial layout of a 4 qubit quantum circuit and I want to map the qubits to a 5 qubit quantum computer. As only 4 out of the 5 qubits will be used, Qiskit ...
2 votes
2 answers
968 views

Why does Parity mapping allow 2 qubit reduction?

when mapping from fermionic to qubit hamiltonian, using Parity mapper allow us to reduce 2 qubit in the final hamiltonian. I would like to understand which kind of symmetries are being used and how it ...
3 votes
1 answer
221 views

Is it possible to build a "Quantum Karnaugh Map"?

Is it possible to build something similar to the Karnaugh Map but instead of classical bits input and output with qubits input and output?
1 vote
0 answers
55 views

Question about performing VQE with an embedded Hamiltonian

Say I have a physical Hamiltonian $\mathcal{H}$ which is $D$-dimensional and I encode it into a larger matrix $M$ which is $\Delta$-dimensional. In the cases I care about $\Delta$ is strictly greater ...
0 votes
1 answer
74 views

General Ehrenfest Theorem applied to N-qubit system operator

Please advise if the following short calculation of the derivative of the expectation value of an all spin Pauli-$\hat{Y}$ operator (acting on a $N$-qubit system) is consistent: The general Ehrenfest ...
1 vote
1 answer
140 views

Time execution on real quantum backend higher than classical kmeans

I am running some experiments on a real quantum backend of IBM with qmeans approach. My dataset has 2 features (2 dimensions). I observe higher execution time on the Quantum Calculate Distance routine ...
3 votes
1 answer
998 views

Coupling maps in quantum computation

Perhaps a bit naive question from my side, but I could not find any satisfactory answer elsewhere: What exactly are the coupling maps in quantum computation and, more particularly, how do those maps ...
0 votes
1 answer
71 views

How to re-order logical qubit location into desired state?

Now, I'm studying about qubit mapping. When the mapping is done, the logical qubit will be randomly mapped to physical qubit. But I want to move the logical qubit location into desired state. For ...
1 vote
1 answer
102 views

How to re-ordering physical qubit location into desired one?

Suppose original quantum circuit have 4 qubits and some quantum operation. Also suppose the result of original quantum circuit state is '1100'. Then apply qubit mapping then mapping state is like ...
0 votes
2 answers
208 views

How to assemble two quantum circuits whose qubit mapping states are different each other?

I uploaded similar question before, but the answer was not I want. I think I should show you in more detail about my question. I use SABRE algorithm which can do qubit mapping for executing quantum ...