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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Are there hardware platforms that natively implement parametric two qubit gates?

For example, is it possible to implement RXX gate with an arbitrary angle on an ion computer in a single native operation? The RXX gate with an arbitrary angle can be decomposed into two RXX gates ...
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How to set the meas_level and optimization_level in Quantum Azure IonQ provider?

I am performing a benchmark process using the Azure Quantum IonQ provider. I use Qiskit in the Azure platform, and I was trying to see how to control the transpiling and compiling process. It seems ...
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Find minimum eigenvalue of an Ising Hamiltonian combined with Error Mitigation

I am currently working on a variation of the Traveling Salesman Problem. For which I use the QUBO(Quadratic Unconstrained Binary Optimization). Within Qiskit there are potent functions to obtain the ...
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2 votes
1 answer
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Can ancilla-based parity measurements be used to detect errors in NISQ algorithms?

Measuring stabilizer eigenvalues is a fundamental part of quantum error correction. However, I was wondering if the idea of measuring a stabilizer using an ancilla could be useful in other contexts as ...
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Surface Code Eigenstates as Circles

I learned that logical $|0\rangle$ of surface code, is an eigenstate, where all stabilizers are +1 value, and since the z-stabilizer is enforcing an even amount of edged in each node, and the x-stab ...
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Code Length of most Naive Repetition Code

What is the formula or answer to the following coding: I would like to get logical qubit with logical error rate of $P_L=1E-10$ or $P_L=1E-19$ for Shor's algorithm, but I would like to know how many ...
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Add noise_model when using 'ibmq_qasm_simulator' backend and provider.runtime.run() function

I am trying to test some qiskit code that employs readout-error mitigation using the ibmq_qasm_simulator backend and Qiskit Runtime. I am getting the backend as ...
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Qubit State (theta,phi) Dependence on the Readout Error

Do the readout errors on the publicly available IBM quantum computers have any dependency on the state being measured? That is, if we are measuring a qubit in the state $\cos({\theta/2}) |0> + e^{i\...
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3 answers
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Surface Code - Convert Control Error to Clifford Error

I am simulating surface code, in order to find the logical error as a function of control error in my circuit. Each of my data qubits is multiplied in control error = a unitary matrix $U$ which is ...
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How to calculate the number of qubits in surface code, for given physical error rate

I am working on improvement of physical qubit error probability. I would like to know: how to calculate the size I need for surface code, given that I need that the logical error probability will be ...
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Why does making a quantum circuit more noise resilient make it easier to simulate classically?

I was reading Quantum Computing in the NISQ era and beyond (John Preskill, 2018) but I didn't get this point on pages 9-10: There is a substantial opportunity for experimentalists and theorists, ...
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Correcting Coherent errors with Surface Codes

Following this article: Correcting coherent errors with surface codes I wonder about the modeling of coherent error and its effect on syndrome after measurement. They say that applying U on the ...
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Which improvements can we expect in Quantum Error Correction?

According to this article: The surface code is currently the most widely pursued quantum error correction scheme (Emphasis mine). It is also said: However, there are drawbacks to the surface code, ...
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How can I add readout error in constructing a quantum noise model?

I'm trying to construct a quantum noise model with readout error only: qiskit.providers.aer.noise.NoiseModel.add_readout_error. However, when I try to specify the ...
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Nyquist–Shannon sampling theorem for Quantum Evolution

In classical digital signal processing one can try to identify the dynamics of a system by sampling its evolution from an initial time $t_0$ to a final time $t_1$. Sampling $N$ times results in a ...
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Confusion about Mitiq folding for zero noise extrapolation

I'm reading the mitiq zero noise extrapolation documentation and I just can't make sense of how the scale_factor for folding work. "The minimum scale factor is one (which corresponds to folding ...
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3 votes
1 answer
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How to use Clifford Data Regression for the MaxCut Problem

i read about Clifford Data Regression in https://arxiv.org/pdf/2005.10189.pdf. If I have understood this correctly, then one receives the mitigated expected value of an observable from CDR. For the ...
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Is it possible to use the mitigation process on a teleportation circuit?

Is it possible to use the mitigation process on a teleportation circuit? Sorry, i'm still starting, if someone can get me out of this doubt, I would appreciate it. The circuit I'm trying to make this ...
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Is there a faster way to do real-time error mitigation in qiskit?

I'm working on the readout error mitigation on a set of results obtained from different quantum circuits. The method I want to apply is to generate the confusion matrix for each quantum circuit (as ...
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How to measure the error rate (or fidelity) of a particular gate (such a H, T) by Qiskit

We know the calibration data of IBM's quantum devices can be retrieved through the randomized benchmarking method, which is included in Qiskit. However, the calibaration data about gates just gives ...
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About qiskit's error mitigation

In qiskit, the error correction using least squares is apparently in qiskit-ignis/qiskit/ignis/mitigation/measurement/filters.py, source code from github and reads: ...
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Manual measurement error mitigation returning a negative number of counts

I have a simple 2 qubit circuit which I am trying to protect from errors using the measurement error mitigation technique laid out here: https://qiskit.org/textbook/ch-quantum-hardware/measurement-...
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Guide for Qiskit's Measurement Error Mitigation?

I'm reading about error correction mainly in the Qiskit Measurement error mitigation chapter contains what it seems and easy way to "clean up" the noise obtained in the IBM (or NISQ) devices....
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7 votes
2 answers
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Apply readout error mitigation to mid-circuit measurement

I'm trying to construct a quantum circuit with 3 mid-circuit measurements, here's an example: ...
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2 votes
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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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1 answer
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Filtering a set of results obtained from job manager

I've already generated a filter for readout error mitigation: ...
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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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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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3 votes
2 answers
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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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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 ...
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2 votes
2 answers
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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 ...
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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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2 votes
1 answer
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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 ...
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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 ...
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3 votes
1 answer
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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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0 votes
1 answer
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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 ...
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2 votes
1 answer
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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 ...
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2 votes
2 answers
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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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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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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 ...
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4 votes
1 answer
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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?
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