7 votes

Apply readout error mitigation to mid-circuit measurement

That's a very interesting question, I haven't thought about it before, thanks for that! Now, the way I see this, you have 2 different potential paths to investigate. 1 The first one would be the same ...
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  • 2,394
5 votes
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Randomness using simple parallel Hadamard circuit

The issue is that you are using noisy hardware with imperfect operations and measurements. In particular, the most likely problem here is that after you prepare a qubit it immediately begins decaying ...
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5 votes

How to implement gate error mitigation in Qiskit?

One thing you can do is zero noise extrapolation. The idea of the technique is to deliberately add noise to your circuit (by stretching the duration of the pulses of your circuit: Extending the ...
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  • 81
4 votes

Why does making a quantum circuit more noise resilient make it easier to simulate classically?

If your quantum circuit mitigates noise, it can also mitigate the approximations in a simulation. It can allow you to use a noisier more-approximate cheaper-to-run simulation. Of course, the noise you ...
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  • 23.2k
4 votes
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What is the difference between Error Mitigation (EM) and Quantum Error Correction (QEC)?

The basic difference is that QEC involves the detection and correction of errors that occur during computation, while EM schemes allow errors to occur and try to compensate for the negative effects of ...
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  • 4,877
4 votes

What is the difference between Error Mitigation (EM) and Quantum Error Correction (QEC)?

Error correction: make each shot good Error mitigation: extract good signal from bad shots Error mitigation focuses on techniques for noticing that a shot is bad, or for quantifying how a shot is bad. ...
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3 votes

IBM Melbourne quantum computer performance and errors

There are many factors that going into this, but most of them are boiled down together into a metric that IBM called Quantum Volume (QV). ibmq_vigo has a QV of 16: Where as ibmq_16_melbourne as QV of ...
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3 votes
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Manual measurement error mitigation returning a negative number of counts

Unfortunately, the Qiskit textbook does not cover this topic correctly. In general you do get negative values when inverting the calibration matrix. These are called quasiprobabilities. You can use ...
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  • 2,159
3 votes

Guide for Qiskit's Measurement Error Mitigation?

Measurement error, as the name says, is the error that is added to the qubits when you try to measure them. In this paper Mitigating measurement errors in multi-qubit experiments you can find ...
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  • 81
3 votes
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Is it possible to use the mitigation process on a teleportation circuit?

I think what you could do is measure the bits, and then possibly flip the answer based on whether a drawn random number is less than the error rate associated with the outcome, i.e the error rates of ...
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  • 2,159
3 votes
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Is there a faster way to do real-time error mitigation in qiskit?

In general, measurement errors do not change on timescales as fast as you are implying here. The data for the readouts is populated once a day or so, and is quite good over that time frame. There ...
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  • 2,159
3 votes

How can I add readout error in constructing a quantum noise model?

I figured out the problem. We should add the noise separately for each qubit, instead of finding the total matrix and then constructing the noise model: ...
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  • 2,228
3 votes
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Nyquist–Shannon sampling theorem for Quantum Evolution

In order to apply Nyquist-Shannon sampling theory, we need to know the maximum frequency that will be present in the signal we intend to measure. We will do this by rewriting a time-dependent ...
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  • 4,877
3 votes

Apply readout error mitigation to mid-circuit measurement

Yes! You would need 3 times the number of classical registers to store each measurement. Please see this. ...
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3 votes
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Filtering a set of results obtained from job manager

As mentioned above, there're 4 types of data that match the requirement. The results in this case obtained from the job manager is not the same as the results shown ...
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  • 2,228
3 votes

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

"what are the advantages and disadvantages in the determination of the calibration matrix each time that we do an experiment and mitigate its error?" Advantage: The noise matrix will be a ...
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3 votes

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

Yes, if we have fixed backend, number of qubits, and noise model (e.g., Basic device noise model in https://qiskit.org/documentation/stubs/qiskit.providers.aer.noise.NoiseModel.html#qiskit.providers....
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  • 136
3 votes

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

I tried to run your code with the same backend as you, ibmq_ourense, and also got the same kind of bad results. Although, I also tried on other backends, first the <...
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3 votes
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How to do error mitigation on the ibmq_16_melbourne?

I think in this case you can split the experiments into multiple jobs. The idea is that you split measurement calibration circuits generated by complete_meas_cal ...
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3 votes
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Specifying qubits to achieve measurement error mitigation on Qiskit

You can achieve this by providing a seed to the transpiler which guarantees that the layout will be the same every time you run it. This can be done as follows ...
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3 votes
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Surface Code - Convert Control Error to Clifford Error

Answer from the literature Background The question of the validity of the incoherent approximation is explored in detail in this publication: Bravyi, S., Englbrecht, M., König, R. et al. Correcting ...
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3 votes

What is the difference between Error Mitigation (EM) and Quantum Error Correction (QEC)?

Here is a partial answer for the questions you've made. Quantum Error Mitigation is a way of mitigating errors in NISQ devices. When full Quantum Error Correction will be possible there will be no ...
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  • 1,626
2 votes
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Mitigating the noise in a quantum circuit

I will provide some general comments concerning noise in quantum computers. Noise in quantum systems is normal phenomena as these systems are probabilistic by nature. Under current state of ...
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2 votes

How to implement gate error mitigation in Qiskit?

One naive way is based from this paper, Cloud Quantum Computing of an Atomic Nucleus, by adding odd number of CNOTs gate to the circuit and do extrapolation. It is kinda hand wavy and you hope that it ...
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2 votes
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How to use Clifford Data Regression for the MaxCut Problem

Almost all error mitigation methods (including CDR) help reduce errors in expectation values and are not suitable to mitigate single-shot experiments. So, in the context of a quantum variational ...
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2 votes

Why does making a quantum circuit more noise resilient make it easier to simulate classically?

As noise goes bigger, so bigger codes are needed to fix it. In a quantum computer, every 1 logical qubit, is encoded into n physical qubits, in order to find the errors. you can make smaller n if ...
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2 votes
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How to calculate the number of qubits in surface code, for given physical error rate

The current gold standard method for this is to simulate various error rates and code distances, and do a linear fit of code distance vs log logical error rate. This allows you to project the code ...
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2 votes

Surface Code - Convert Control Error to Clifford Error

No it's not literally equivalent, but it's close enough. I'm not going to go through working out all the math, but here are the key things you need. Decompose your coherent errors into linear ...
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2 votes
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Surface Code Eigenstates as Circles

All those three cases are different quantum error correction codes. First toric code has periodic boundary condition, but second one which is surface code has boundaries. Lastly third one is rotated ...
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2 votes
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Implementing Readout Error in my circuit seems to have no effect whatsoever

Replace meas.measure(range(3), range(3)) with: meas.append(Instruction("measure", 3, 3, []), range(3), range(3)) ...
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