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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4
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1answer
97 views

IBM Q devices' hardware/resource constraints

I tried to look for the resource constraints but so far haven't been able to find them. They are not present in the GitHub repository that usually provides the hardware information for the different ...
2
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1answer
96 views

How call from IBM Q Experience (Jupyter Notebook) cplex

I have the latest version of cplex (12.9) installed on my computer. I use it very well with Jupyter notebook, but in IBM Q Experience, I did not get way to call it. IBM Q Experience warns me that the ...
3
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1answer
81 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 ...
1
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2answers
78 views

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 ...
0
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1answer
52 views

No backends assigned to my Account

When I open my account on IBM Quantum Experience, I am shown 9 backends that are assigned to me. But when I open any of my circuits, I get the error that "This account has no backends assigned&...
4
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1answer
63 views

Measure $\langle \hat{X}\rangle$ and $\langle \hat{Y}\rangle$ from counts

I'm confused about how I can measure $\langle \hat{X}\rangle$ and $\langle \hat{Y}\rangle$ using counts. Here's my code for X: x-basis: ...
0
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1answer
38 views

This is a question about IBM quantum circuit used to generate the quantum cheque state

I'm learning about quantum cheque. And I read "Experimental realization of quantum cheque using a five-qubit quantum computer" which is written by Bikash K. Behera ,Anindita Banerjee and ...
0
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1answer
162 views

Unable to instantiate provider for research account locally

When I run IBMQ.load_account(). I have the error information: ...
2
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1answer
53 views

How to Implement a noisy identity gate on qiskit?

I can successfully implement the U gate (single qubit) on qiskit, but when I am trying for the identity operation it is not showing any differences with the ideal one .
0
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1answer
84 views

Long running time at job

I try to launch QSVM algorithm (from Qiskit example ) on all real quantum devices (that is IBM Q) and get running time 5-30 seconds on one job. But if I use ...
0
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1answer
107 views

Quantum circuit not giving right results

I am trying to write a quantum circuit that implements swapping. The initial state is $$\phi^+_{12}\phi^+_{34},$$ where particles $(1,4)$ belong to $A$ and $(2,3)$, belong to $B$. After A's ...
0
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1answer
276 views

ERROR_RUNNING_JOB with 32 qubit circuit running on ibmq_qasm_simulator backend

I recently made a quantum circuit that uses 32 qubits and try to run it on IBM Q Experience qasm_simulator backend. But it always ends with ERROR_RUNNING_JOB. ...
2
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1answer
128 views

API error when trying to access IBM Quantum Computer using IBMQ API Token

I'm trying to write a code so that if the token exists then it loads the account or else it asks the user for the API token. Below is the code for reference: ...
13
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2answers
5k views

How to implement the 4 Bell states on the IBM Q (composer)?

I would like to simulate the 4 "Bell States" on the IBM composer? How can I best implement those 4 Bell states using the existing set of gates ? Here below you see the definition of the 4 Bell ...
1
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1answer
40 views

Job ids retrieval from ID. Big set of jobs

I'm in the need of running a lot of jobs in the IBM backends. If one likes to run in parallel two jobs (say, with two different parameters), I have seen in the Jobs ...
0
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1answer
28 views

What are the runtimes of the different modes of qiskit's mcx?

Qiskit's mcx has four different modes: 'noancilla': Requires 0 ancilla qubits. 'recursion': Requires 1 ancilla qubit if more than 4 controls are used, otherwise 0. 'v-chain': Requires 2 less ancillas ...
2
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1answer
100 views

Why I am not getting approximate equiprobable states in the following circuit on IBM Q simulator?

I have the following circuit which consists of symmetric modules. I compiled the circuit in IBM Quantum experience backend - ibmq_qasm_simulator, 8192 shots. The result is not equiprobable. Why? Since ...
0
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1answer
52 views

JSONDecodeError with backend.run

I'm trying to follow tutorial on pulse simulation described in qiskit.org. The generated PulseQobj is well executed with AER simulator, but it throws JSONDecodeError when using real backends (ex. ibmq-...
0
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1answer
26 views

FileNotFoundError: No such file or directory. This error occurs while giving a data path to upload datafile(present on desktop) in IBMQ

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 ...
1
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1answer
55 views

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?
3
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0answers
60 views

“503: Server Unavailable. Your server appears to be down. Try restarting it from the hub”. Help

This message is popping continuously for 2 days in my IBM Quantum lab. I have tried logging out and in again, restarting the browser, changing the internet connection, and changing the device but this ...
2
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0answers
46 views

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 ...
5
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2answers
260 views

Moore's law for quantum computers

Moore's law states that performance of classical computers doubles every two years (later revised to 18 months) and a price for computing resources halves during same time period. Currently, it seems ...
1
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1answer
43 views

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 ...
0
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1answer
51 views

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 ...
1
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1answer
84 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 ...
3
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1answer
117 views
0
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1answer
38 views

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 <...
2
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1answer
28 views

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 ...
0
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1answer
84 views

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} &...
4
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4answers
231 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 ...
0
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1answer
45 views

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 ...
-1
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1answer
30 views

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 ...
2
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1answer
199 views

Error when running HHL algorithm in Qiskit

I tried to solve a simple system of two simultaneous linear equations in with HHL algorithm in Qiskit. In particular the system is $Ax=b$, where $$ A = \begin{pmatrix} 1.5 & 0.5 \\ 0.5 & 1.5 \...
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0answers
34 views

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 ...
1
vote
1answer
173 views

How to obtain the density matrix using tomography in the real device?

I am trying to run the QFT algorithm for n=5 (n number of qubits). The number of experiments that it generates is bigger than the one allowed by the IBM devices (i.e. 75). Therefore, I have tried to ...
1
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1answer
105 views

How to get running time for each circuit executed on IBM's quantum processors in one round?

I want to execute multiple circuits in one round on IBM's backends, especially the 16-qubit one, to save time. For instance, ...
2
votes
1answer
121 views

How can I find the fidelity of the preparation operation $|0\rangle$ of IBMQ?

I want to know the fidelity (or error rate) of the preparation of $|0\rangle$. How can I obtain it?
3
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1answer
81 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 ...
0
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1answer
47 views

How to re-execute failed jobs in qiskit?

When executing a batch of circuits using the IBMQJobManager and attempting to combine all the results of all jobs with combine_results I get the ...
2
votes
1answer
74 views

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 ...
6
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2answers
258 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: ...
2
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1answer
62 views

IF statement in OpenQASM2.0 on IBM Quantum Experience — error

I have written the following toy .qasm file, which has some adaptive measurements: ...
1
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1answer
43 views

IBM Circuit Composer pane is blank

I'm new to IBM Quantum Experience. When I initially create a circuit using the composer, all is well, but when I save the circuit and open it again, the composer window is blank - no gates or wires. I ...
5
votes
3answers
304 views

How do I get out 2 measurements from the same execution on Qiskit?

Here's my circuit, trying to checkout the effect of measurement on the IBM Q circuit. Here you can see I do 2 different measurement at different time, and I hope to be able to see both results. ...
1
vote
1answer
75 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 ...
11
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3answers
2k views

Implementation of the oracle of Grover's algorithm on IBM Q using three qubits

I am trying to get used to IBM Q by implementing three qubits Grover's algorithm but having difficulty to implement the oracle. Could you show how to do that or suggest some good resources to get ...
2
votes
1answer
63 views

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 ...
1
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1answer
77 views

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....
1
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1answer
83 views

Braket and Q# Simulators

I have implemented Shor's algorithm in Qiskit, and everything works as expected within the IBM Q experience for both the IBM qasm_simulator and real hardware. However, after I've implemented Shors in ...

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