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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Uncorrectable error due to error on ancilla qubit

Consider a controlled-NOT (CX) gate between the two qubits, implemented with an interaction of the form $ \widehat{H}_{\mathrm{CX}}=V\left[\left(\frac{\hat{I}_1+\widehat{Z}_1}{2}\right) \otimes \hat{I}...
Aubrey Sharansky's user avatar
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Where have the error mitigation utilities moved to in Qiskit?

Now that Qiskit Ignis has been deprecated where have the error mitigation utilities been moved to? I am unable to find that by doing a quick google search.
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Lindblad under time rescaling: Zero noise extrapolation

This question is related to an earlier post Zero noise extrapolation for error mitigation: Meaning of rescaled density matrix, specifically when there is no local hamiltonian evolution If I have the ...
lost forgotten pearl's user avatar
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Probabilistic error cancellation: how are we sure (i) the inverse noise *mathematically* exists, (ii) its expansion contains implementable operations

I am currently learning the basics of probabilistic error cancellation. The idea, in summary, is the following: We want to implement a quantum circuit having a noiseless (unitary) implementation $\...
Marco Fellous-Asiani's user avatar
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Zero noise extrapolation for error mitigation: Meaning of rescaled density matrix, specifically when there is no local hamiltonian evolution

I have a few questions regarding dynamics rescaling for zero noise extrapolation. In the paper Error mitigation for short-depth quantum circuits, in equation (30), they write We redefine $T \...
lost forgotten pearl's user avatar
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Bounds on success probability of an algorithm under depolarizing noise

The problem I have is that, I have a quantum circuit performing a certain task (e.g. Shor's algorithm) and the circuit is subject to depolarizing noise, Pauli errors, after each gate. And I want to ...
AndyLiuin's user avatar
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how does one get native 2-body measurements?

How are Majorana-based architectures able to possess native 2-body measurement operations? Could anyone provide an appropriate reference explaining that? Are those native measurement operations ...
user111's user avatar
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How to transform a qiskit quantum circuit to a braket circuit?

I have a quantum circuit in qiskit. Now I want to know is there any way that I can transform it to a braket circuit in AWS? I want to use error mitigation in AWS. I have the circuit in qiskit. But as ...
INDRANIL MAITI's user avatar
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Measurement of readout errors for error mitigation algorithms

I am using an error mitigation algorithm that uses the readout errors p(0|1) and p(1|0) to correct the errors due to noise in my original circuit. I am trying to measure the readout errors in the same ...
bisarch's user avatar
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Qiskit, possible to manipulate mid-circuit measurement outcomes?

I'm currently coding up an error correction gadget using qiskit. The one I'm doing now is 7-qubit Steane code with Steane's error correction gadget, in which the ancilla qubits are measured and then ...
AndyLiuin's user avatar
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How is randomized compiling actually helpful: experimentally, a gate is not "perfect" followed by some noise acting "after"

I am currently learning randomized compiling with this paper which seems to be the "main" reference on this topic (at least many papers refer to this one). However, I do not understand how ...
Marco Fellous-Asiani's user avatar
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What do the 'resilience_level's in qiskit-runtime's primitives mean?

The qiskit-runtime primitives programs 'estimator' and 'sampler' for accessing the IBM Q hardware have the option of error mitigation by setting the 'resilience_level'. Here an overview of the meaning ...
qcabepsilon's user avatar
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How is Pauli twirling applied to a noisy gate in practice?

My understanding of Pauli Twirling mainly comes from this paper. Please, correct me if I am wrong in any part of my explanation. General idea of Pauli twirling The idea of Pauli Twirling is the ...
Marco Fellous-Asiani's user avatar
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Time Complexity (Big O Notation)

What is the time complexity of the two error-mitigation methods that are implemented in qiskit.ignis. 1- pseudo inverse. 2- least squares.
rabah hacene benaissa's user avatar
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Which error channel definitions should I use if I want to compare the performance of a QEC protocol for depolarizing errors vs dephasing errors?

Let's say you want to investigate if a quantum error correction or error mitigation protocol performs better under dephasing errors compared to depolarizing errors, or if a quantum algorithm is more ...
Turbotanten's user avatar
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Does anybody know what a low-degree Markov field is?

In the paper Fast Estimation of Sparse Quantum Noise I saw the following description: quantum devices approaching the fault-tolerant regime will have very few significant errors (and therefore are ...
KarryMa's user avatar
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Are there any systematic tools for estimating expected error rate?

Like we all probably know, today’s NISQ computers are, as their name implies - very noisy. Hence, if we desire to obtain valuable results then we should come up with circuit designs that minimizes the ...
Ohad's user avatar
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Best tutorial about the variational quantum eigensolver (VQE)

I want to find a tutorial on VQE with a good valance between the theoretical background of the method, and it's working implementation on QPU. Covering advanced topics such as quantum error ...
user3116936's user avatar
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Is there a tutorial for error mitigation in qiskit that does not use the deprecated ignis?

Working through the qiskit text I have come accross measurement error mitigation a few times (Measurement Error Mitigation, Lab 3: Quantum Measurment,...]. In the online textbook the coding indicates ...
PGibbon's user avatar
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What is more important, minimizing the number of gates, or the number of qubits?

I am new to the quantum world, and I have 2 circuits that measure cosine similarity between 2 binary vectors. One uses a swap test, the other uses something called a hyper-state generation procedure. ...
Yousef Zook's user avatar
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3 answers
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What is the difference between Error Mitigation (EM) and Quantum Error Correction (QEC)?

From what I understood, EM is mostly post-processing and does not affect quantum circuit complexity whereas QEC has overheads and integrates as part of a quantum circuit. Is this correct? Also, which ...
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Options for more complex error models on stim?

We're trying to simulate whether some initialization strings are preferable to others. For example, would initializing all qubits to $|0\rangle$ lead to a lower error rate? Is it possible to further ...
xilinzhou's user avatar
1 vote
1 answer
252 views

What is the concrete difference between qiskit thermal_relaxation_error and phase_amplitude_damping_error?

What is the concrete difference between those two error models in qiskit.providers.aer.noise? For phase_amplitude_damping_error ...
qcabepsilon's user avatar
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Readout Error in Qiskit: What is a reasonable model?

The Readout Error in Qiskit is described here: https://qiskit.org/documentation/stubs/qiskit.providers.aer.noise.ReadoutError.html Although it is easy to obtain such an error for 1-qubit for IBMs ...
Marion's user avatar
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Implementing Readout Error in my circuit seems to have no effect whatsoever

I am trying to perform a simulation using Qasm in order to see how the readout error actually affects my circuit. The circuit I am implementing is a trivial one, the three qubit one that implements ...
Marion's user avatar
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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 ...
Camilo160's user avatar
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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 ...
Lior's user avatar
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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 ...
Ron Cohen's user avatar
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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 ...
Ron Cohen's user avatar
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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 ...
Ruth V.'s user avatar
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1 answer
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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\...
user206444's user avatar
2 votes
3 answers
226 views

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 ...
Ron Cohen's user avatar
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2 votes
2 answers
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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 ...
Ron Cohen's user avatar
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4 votes
3 answers
374 views

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, ...
Fezudo's user avatar
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1 answer
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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 ...
Ron Cohen's user avatar
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5 votes
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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, ...
Tristan Nemoz's user avatar
4 votes
1 answer
158 views

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 ...
ZR-'s user avatar
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4 votes
1 answer
120 views

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 ...
Marion's user avatar
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2 votes
1 answer
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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 ...
Ahmed Malik's user avatar
3 votes
1 answer
171 views

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 ...
qrafix's user avatar
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1 vote
2 answers
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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 ...
Ikky R's user avatar
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2 votes
1 answer
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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 ...
ZR-'s user avatar
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1 vote
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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 ...
jojo's user avatar
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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: ...
user2820579's user avatar
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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-...
LOC's user avatar
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1 answer
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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....
user2820579's user avatar
8 votes
2 answers
455 views

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: ...
ZR-'s user avatar
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2 votes
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45 views

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, ...
peachnuts's user avatar
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Filtering a set of results obtained from job manager

I've already generated a filter for readout error mitigation: ...
ZR-'s user avatar
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1 vote
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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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