Questions tagged [ibm-q-experience]

Use this tag for questions about IBM's Quantum Service - Circuit Composer & Quantum Lab. DO NOT use this for questions about general Qiskit issues (use [qiskit] for that).

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Does dedicated mode provide better results than fairshare in mid-circuit measurement?

I'm using a research account and I have a question about running circuits with (dedicated/priority mode) and without reservation (fair-share mode). From the documentation of dedicated mode, This (The ...
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Measuring the accuracy of a circuit output?

I have created a circuit and got the output which matches the truth table but, I'm not understanding the measuring the circuit output in terms of the probabilities, power or error. This is the circuit ...
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Why the last IBMQ job of my VQE have just one circuit?

I am running a VQE over the H2 molecule on ibmq_quito and I set a callback function to save all jobs id's of all iterations. When I check the penultimate job (and the previous ones), I have 2 circuits ...
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Random accuracy using VQC and Iris dataset

Using the same seed (seed_simulator and seed_transpiler) I get different accuracy when running it several times. In Aqua library (from qiskit.aqua.algorithms import VQC) I solved it adding ...
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161 views

How to download from IBM Quantum lab folder of data .txt files all at once?

I have a script in the IBM Quantum lab which runs several jobs and stores the result of each job as a .txt file in a results folder. All I want to do is to download the folder of files. I cannot ...
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2 votes
1 answer
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how can we save a model using qiskit_machine_learning?

How can we save a trained model using Qiskit Machine Learning library? I've built a VQC classification model and once finished, I'd like to save the different models to be loaded later. There is a <...
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2 votes
1 answer
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Adding collaborator to project during reservation

If I add a collaborator to an IBM Quantum Education project during a system reservation, do they immediately get priority access to the reserved system? Or do I need to add them before the ...
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1 answer
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How to build and visualize circuit from matrix?

In paper Efficient quantum algorithm for solving travelling salesman problem: An IBM quantum experience, the authors use gate $U_j$ and its decomposition $$ U_j = \begin{pmatrix} \mathrm{e}^{ia} &...
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2 answers
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Trying to connect IBM Quantum to External API

Is it possible to connect a quantum computer to openlibary.org API? How do I find the public IP address to my quantum instance?
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1 answer
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How can I simulate the Avg CNOT Error on IBMQ Backends?

I want to know exactly how to estimate the Avg CNOT Error rate for IBMQ Backends? For instance, I tried to estimate the Avg CNOT Error rate for Belem Backend; I randomly prepared the 00,01,10,11 ...
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-1 votes
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FileNotFoundError: No such file or directory. This error occurs while giving a data path to upload datafile(present on desktop) in IBMQ [closed]

I am trying to implement https://qiskit.org/textbook/ch-machine-learning/machine-learning-qiskit-pytorch.html#3.-Let's-code!- in IBMQ using a dataset present on my desktop. While uploading a dataset ...
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What is this pulse experiment showing?

The following results in the figure were achieved using Qiskit pulse by doing the following pulse sequence; { $\frac{\pi}{2}$, delay $\tau$, $\pi$, delay $\tau$, $\frac{\pi}{2}$} The figure is the ...
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Recover qubits used in an actual computation

How do I recover from a certain job_id in the IBM backends which qubits where used? I would be interested to know if for instance, in a batch of say 50 jobs, 25 of ...
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2 votes
1 answer
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How to find the expectation value of several circuits using Qiskit aqua operator logic?

I am using the method from this SE answer to calculate the expectation value using qiskit aqua operator logic which works well for a single circuit. Here is a simplified code snippet to demonstrate ...
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3 votes
2 answers
139 views

When will Qiskit Runtime be available to all users?

IBM's Qiskit Runtime was recently made available to a select group of users. Have they announced when it will be available to all users or when they might open it back up to a second round of new ...
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1 answer
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IF statement in OpenQASM2.0 on IBM Quantum Experience -- error

I have written the following toy .qasm file, which has some adaptive measurements: ...
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How do I identify a VQE job run in real hardware?

I am running a VQEUCCFactory for H2 on a real hardware device. ...
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1 vote
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....
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1 answer
196 views

How do I send a quantum circuit to IBM for execution?

I have, let's say, the following quantum circuit: The QASM code of this quantum scheme has the following form: ...
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2 answers
323 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: ...
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2 votes
1 answer
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QPE Circuit test on Quantum Computer ('ibmq_16_melbourne')

After several atempts, I cannot mitigate the error when running the code on a NISQ, via the qiskit library (more specifically on the 'ibmq_16_melbourne'). I've already mapped the connected qubits and ...
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3 votes
2 answers
438 views

How can I specify the qubits on quantum computers that I want to use?

Suppose I have the following 2-qubit quantum circuit: ...
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2 votes
1 answer
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"us" units on relaxation times $T_j$ in the IBM backends

A pretty lame question but, the backends relaxation times $T_1,T_2$ are given in us units. What are those? (Frequencies are given in GHz... Is it really $\mu s$ but IBM can't display the $\mu$ in the ...
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2 votes
1 answer
302 views

$T_1/T_2$ thermal relaxation example

The built in noise models in Qiskit have an example of $T_1/2T_2$ relaxation here. I have a couple of doubts; the notebook is not very clear in some of the steps. Why does one need $T_2\leq 2T_1$? ...
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1 vote
2 answers
183 views

Qiskit Pulse Notebook

When I downloaded the source code from Qiskit Notebook Accessing Higher Energy States and tried to execute it, the output and graph seem wrong in the step finding the frequency step which leads to the ...
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2 votes
1 answer
157 views

IBM Quantum API for Java Developers

As far as I know, IBM Quantum provides two types of APIs: one for Qiskit, and the other for third-party uses (API for developers). In this question, there are several arguments about using the API for ...
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3 votes
2 answers
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Data embedding using IBM quantum composer

How do you use the IBM quantum composer to encode some data $(a,b,c,d)$ represented by a vector ket in which $a,b,c,d$ have been normalized to one? $a|00\rangle + b|01\rangle + c|10\rangle + d|11\...
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1 vote
0 answers
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issues running a 32 qubit grover's algorithm

I have a 32 qubit grover's algoritm however whenever I run it on the simulator that IBM offers it always ouputs a probability of 1 on every single result. Is there a way to run circuits larger then 32 ...
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1 vote
1 answer
78 views

Qiskit Portfolio Optimization : Does the resulting matrix show the stock combination to select?

The IBM Qiskit Portfolio Optimization sample finally provides an array similar to [1,0,1,1] representing the 4 digits as the stocks. So does the ...
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1 vote
1 answer
121 views

IBM quantum computer giving the wrong result?

This is the first time I am using the IBM quantum computer. I tried to run a circuit (see below the first picture) but the results I got don't match the theoretical results shown (see below the second ...
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2 votes
1 answer
54 views

Time result for my algorithm

I've used the function result.time_taken to know the amount of time used to execute a task on the real chip, but I don't understand if the result is in seconds or ...
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2 votes
2 answers
96 views

Who is responsible for implementing quantum error correction?

There are various options for error correction. For example, the Shore code or a whole class of surface codes. But I don't really understand at what level they should be implemented. For example, I ...
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1 vote
1 answer
81 views

How to import circuit libraries into qiskit

Im trying to put the QFT circuit in my qiskit circuit but im having trouble: ...
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0 answers
64 views

How to simplify a circuit with repeated same parts?

If I have a circuit with 3 qubits and repeated gates as follow: ...
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2 votes
1 answer
146 views

Is RYY gate not available in IBM Quantum Composer?

If so, why? How to create the RYY-gate in the composer?
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3 votes
1 answer
248 views

Qiskit: Transpilation and the CircuitSampler

I am using Qiskit's opflow and its CircuitSampler to evaluate matrix elements / expectation values. Now, going beyond ...
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2 votes
1 answer
179 views

Qiskit logical to physical qubit mapping

I want to run a simulation using qasm with a realistic noise model from a backend, specifying a coupling_map as well as an ...
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3 votes
1 answer
295 views

Is there any way to obtain the number of qubits of a given backend in Qiskit?

I'm testing out a program in different IBMQ mock backends, and I want the program to use the maximum number of qubits in each case. Is there any function/method to extract the number of qubits of a ...
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3 votes
1 answer
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Is there a way to run "in the background" code sent to the IBM backends?

I use different qiskit backends to run my code. Since the maximum number of shots is $2^{13}$, sometimes I need to send the same code several times with a "different ticket". I am wondering ...
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3 votes
2 answers
445 views

Drawing the circuit in Qiskit - how to set same style as in Composer?

A quantum circuit can be visualized in Qiskit with circuit.draw. A drawing style can be set with parameter output which can have ...
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3 votes
1 answer
109 views

Why does running my circuit on Quantum Hardware produce such unexpected resultss?

I am using Jupyter Notebook with Qiskit. I have created a program that can add two 3-bit numbers together. When I simulate this program on a qasm_simulator it works as expected and I can add any two 3-...
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2 votes
1 answer
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Why I am gettting this error when I try to open the Quantum Lab in the IBM Quantum experience?

I am using quantum labs in IBM Quantum Experience to my circuits. But from yesterday onwards (May-03-2021) this error message is being shown on my screen. Does anyone have any idea about this issue?
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2 votes
1 answer
55 views

What is the relationship between the (sx) error rate listed in calibration and the angle/amplitude errors calculated using the fitter?

The IBM Quantum services website lists calibration statistics for their devices, including the (sx) error rate per qubit, which is listed as a single number. One can also manually calibrate a device ...
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2 votes
1 answer
56 views

Can I use the same qiskit account on two laptops?

I have two laptops with different accounts of Jupyter Notebook. I'm wondering can I use the same qiskit account (with the same token) on both laptops? I'm worried that if I run the token on my new ...
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4 votes
2 answers
139 views

Why does applying a Hadamard gate three times to $|0\rangle$ result in a tiny imaginary component in the $|1\rangle$ amplitude?

I'm using qiskit with the online IBM Quantum Lab and when I run the following code ...
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0 votes
1 answer
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4Q Grover circuit working in simulator, however producing nonsense in actual quantum computer

I am a noob at quantum computing but I am certain the circuit is correct. I've tried increasing the number of shots, changing the quantum computer. I think it might be a problem with my ccccx gate? I ...
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4 votes
4 answers
874 views

What is the difference between Bloch's sphere and IBM's Q-sphere?

I'm new to Quantum Computing and I've been trying to understand single-qubit operations, quantum phases etc through Bloch's Sphere visualization. However, in IBM's Circuit Simulator, they seem to be ...
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1 vote
0 answers
129 views

Understanding the heavy output problem [closed]

In this paper (or more pedagogically here) it is given a way to compute the Quantum Volume of a quantum computer (qc), specifically aimed at the IBM qcs. In all this process I found some dark spots ...
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3 votes
0 answers
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What is the actual precision of the IBM quantum computer?

In working with the IBM quantum computer, one can use for example the composer in order to build simple quantum algorithms. Essentially, one usually feeds a phase in order to affect one of the qubits. ...
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1 vote
1 answer
130 views

Can I use Quantum lab during IBM Quantum certification exam? [closed]

Hello I am about to take the IBM Quantum Qiskit dev exam. I don't know if I can use the quantum lab (Qiskit) during the exam. Does anyone know?
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