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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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: ...
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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 ...
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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 .
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1answer
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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 ...
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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 ...
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“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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 <...
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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 ...
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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} &...
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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?
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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 ...
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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 ...
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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 ...
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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 ...
2
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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 ...
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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 ...
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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: ...
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1answer
117 views

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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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....
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1answer
160 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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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: ...
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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 ...
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2answers
378 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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1answer
28 views

“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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1answer
49 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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2answers
105 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 ...
2
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1answer
73 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 ...
3
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2answers
69 views

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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0answers
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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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1answer
46 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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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 ...
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1answer
48 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 ...
2
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2answers
53 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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1answer
34 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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0answers
53 views

How to simplify a circuit with repeated same parts?

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

Is RYY gate not available in IBM Quantum Composer?

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

Qiskit: Transpilation and the CircuitSampler

I am using Qiskit's opflow and its CircuitSampler to evaluate matrix elements / expectation values. Now, going beyond ...
2
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1answer
75 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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1answer
69 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 ...
3
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1answer
40 views

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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2answers
303 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 ...
3
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1answer
80 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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1answer
84 views

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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1answer
37 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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1answer
44 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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