Questions tagged [error-mitigation]

For questions about QEM (Quantum Error Mitigation) which is different from Quantum Error Correction in that no extra qubits are used.

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Crosstalk error of simultaneous cnots

We can use simultaneous randomized benchmarking (SRB) to quantify the crosstalk impact of simultaneous CNOTs. The crosstalk error is caused by many reasons, for example, the always-on ZZ interaction, ...
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1answer
61 views

Filtering a set of results obtained from job manager

I've already generated a filter for readout error mitigation: ...
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1answer
29 views

Can I only use a 'subset' of calibration matrix to reduce measurement errors?

Suppose I have the following calibration matrix generated using 4 qubits: ...
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1answer
62 views

IBM Melbourne quantum computer performance and errors

What is the reason for high variation in measurement probability results of a simple 3/4 qubit measurement circuit on IBM Melbourne machine in comparison with the same circuit being run on IBM Vigo/...
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1answer
58 views

How to implement gate error mitigation in Qiskit?

I have been using the Ignis module for performing error mitigation but it accounts only for the measurement errors. For this reason, I want to know if there is some way to perform gate error ...
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0answers
26 views

There seems to be a bias against states with more 1s, in IBM's calibration matrix generator: What are the consequences and possible solutions?

Qiskit's function CompleteMeasFitter builds a calibration matrix in this way (2 qubit case): Everything is initialized in the state $|00\rangle$, which is the ...
2
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2answers
80 views

Error mitigation matrix as backend property: Are any “reliable” mitigation matrices publicly available?

Given that the error mitigation matrix (meas_fitter.filter) does not vary so much for a given backend and number of qubits, then what are the advantages and disadvantages in the determination of the ...
3
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1answer
157 views

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 ...
2
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1answer
49 views

Randomness using simple parallel Hadamard circuit

I've recently tried to build a Random generator using 5 hadamard gates (shown as U2 below) measured to 5 classical bits in parallel as shown in the circuit image. I've executed this circuit for 8192 ...
2
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1answer
207 views

How to do error mitigation on the ibmq_16_melbourne?

I'm trying to make a calibration matrix using CompleteMeasFitter as in here on IBMQ Melbourne, but I need to use all 15 qubits, which mean it has to run 32768 calibration circuit, far exceeding the 75 ...
3
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1answer
73 views

What do coupling coefficients mean in terms of Pauli gates, and why are they time dependent?

I am reading this error mitigation paper by the IBM team and I am slightly confused about the meaning of "coupling coefficients" when describing multi-qubit Hamiltonian. I have only seen ...
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1answer
99 views

Real-device error mitigation with qiskit

I'm trying to do error mitigation in IBM-Q quantum computers with qiskit. I followed the tutorial here. My thought was that in order to make sure that I'm correcting the qubits that I'm actually using ...
2
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1answer
71 views

Specifying qubits to achieve measurement error mitigation on Qiskit

I'm learning how to do error mitigation on Qiskit as my experiment result differs from the simulated result. I read the tutorial here, but I have some questions about it. If I have understood it ...
2
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2answers
302 views

Mitigating the noise in a quantum circuit

I'm using Qiskit and I have a Quantum Circuit (say, circuit) that gives reasonable results when using the simulator, namely ...
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0answers
32 views

Tensored vs ordinary measurement mitigation runtime

My experiments show that the runtime of actually applying the measurement filter matrices to circuit execution results is much slower for tensored mitigation than ordinary mitigation. Tensored ...
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0answers
218 views

Problem with measurement error mitigation using VQE

I am attempting to mitigate measurement error while running on one of IBM's real devices and am doing so by passing CompleteMeasFitter into ...
3
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1answer
120 views

Existing measurement error mitigation

Does IBM compute a measurement error mitigation calibration matrix that can be accessed from its device properties or somewhere else? Or does the user have to do that every time?