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. As of August 2020, there are 20 processors on the IBM Q Experience ranging from 5 to 53-qubits. Note: Some systems are only available to hubs, partners, and members of the IBM Q network.

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IBMQ: Can I implement a quantum measurement in the middle of a quantum circuit?

I am executing a quantum circuit on an IBM quantum device. The circuit is simple: A single qubit (start from $|0\rangle$), Rx($\pi/2$) Measure (in z) 3 .Rx($-\pi/2$) Measure (in z) The final ...
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How to measure a quantum circuit's execution time on a real IBM device?

I am executing a quantum circuit on an IBM quantum device and I need to start a timer as soon as the job in the queue starts running. I have already used: ...
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IBMQ: “Credentials are already in use”

Executing the following: ...
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1answer
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Error while trying to execute the Quantum Circuits in IBMQ

I have been trying to execute the quantum circuit in the backend of the IBM 16 qubit Melbourne machine. I end up getting ...
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1answer
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Where are my Results?

I've successfully used IBM Q Experience for quite a while now. But the interface seems to have changed. After I run a simulation on my quantum circuit, I go to Results but I don't see the answer in ...
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3answers
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Measurement of 1 qubit in a two qubit system

I created two qubits in IBM quantum experience and measured the second qubit without applying any gate. The result I got had a computational basis of 00 and 10. How does the measurement of the second ...
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1answer
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Recording the time taken by a VQE to find ground state energy

I want to record the time that a VQE solver takes to find the ground state. At the moment I am using: ...
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0answers
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State bug in IBM Quantum Experience

I run many tests with VQC and QSVM algorithms. In last times I can't get final result because some job hang on state Creating, Validating or Running. It can continue many hours and It doesn't finish. ...
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50 views

Length / transpilation issues with Grover's algorithm

I would like to discuss the discrepancies between what we see in the simulator versus what we see in the actual running of the code on any IBMQ machine for any qubits at 5 or above. I am doing a final ...
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1answer
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Can Not Login IBM Quantum Experience! [closed]

When I click the “IBMid” for the first time, I can see the login page and input my username and password. However it return to the initial page(https://quantum-computing.ibm.com/login) and after that ...
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IBM Q - Individual Run Results

In Qiskit, is there a way to get the individual results from each shot on the IBM quantum device (instead of simply the summary statistics)? The result JSON file provides the count of all the 1024 ...
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1answer
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Quantum Phase estimation with $2\pi$ replaced with $2e$

The QPE on IBM platform finds the eigenvalue of a unitary operator, i.e $$U|\phi\rangle=e^{2\pi i\theta}|\phi\rangle$$ and uses the rotation operators as $$U(\theta)=\begin{bmatrix}0 & 1\\ 1 &...
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Gate characteristics of different platforms

I would like to know if there is a place in which is summarized the gate characteristics of the different quantum computer existing (IBM,Google, others). For instance, which kind of two qubit gate ...
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Comparing QSVM & Classic SVM on BigData. Quantum Supremacy

I work on comparing QSVM and Classic SVM (SKlearnSVM) with using Qiskit. I have to show quantum supremacy at 400000-500000 samples but I don't get good results. I have problem with long time training ...
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No histogram appears in my job results

Newbie here - logged in to IBM Q Experience on a MacBook Air with up-to-date OS (macOS Catalina 10.15.7) and Safari browser (14.0). I can build a circuit in Circuit Composer, select a back-end in Run ...
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2answers
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Traveling salesman problem in Qiskit: cannot find a solution on simulator

I am trying to solve Traveling Salesman Problem (TSP) in Qiskit based on Qiskit Tutorial. I used TSP for four cities described by this distance matrix: $$ D = \begin{pmatrix} 0 & 207 & 92 &...
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1answer
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A problem with IBM Q, NameError: name 'iBMQ' is not defined

I 'm trying to reproduce the code given in the Qiskit summer school here. The code is: ...
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2answers
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What's meant by the depth of a quantum circuit?

I'm using Qiskit to create quantum circuits wherein I've this attribute called depth. The documentation states it is the length of the critical path here. What does ...
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1answer
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How to perform this $d$-dimensional unitary operation on IBM Q?

$U_{a,b}=\sum^{d-1}_{x=0}\omega^{bx}|x+a\rangle\langle x|$,$\omega=e^{\frac{2\pi i}{d}}$,$a,b\in\{0,1,2,...,d-1\}$ Can someone please give me the pic of the quantum circuit?
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1answer
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Bernstein-Vazirani Gate IBM Q Noise

When running the attached Bernstein-Vazirani gate on IBM Q, with 1024 shots on ibmq_16_melbourne, I receive the expected result of "00110" with 26.563% success. I notice that there is a lot ...
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1answer
32 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&...
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2answers
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How to verify teleportation was successful in this circuit?

In this circuit (link), q0 is Alice's qubit and q1, q2 are entangled qubits given to Alice ...
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1answer
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Composing teleportation circuit in Qiskit Circuit Composer

I'm trying to create the teleportation circuit in IBM Qiskit Circuit Composer. ...
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3answers
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How can I obtain transformation matrix of a quantum circuit in the Qiskit?

I need to draw a quantum circuit in Clifford+T library and obtain automatically its transformation matrix. Is there any feature on Qiskit in this case?
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Unable to run a QRNG code

I am trying to run the above code on Vigo, Santiago and other backends. However, warning message as shown in the image apppears and no result is displayed even after hours of waiting. However, when I ...
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1answer
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How to set overwrite to true with IBMQ?

I'm trying to get setup with https://qiskit.org, but I'm having a problem. I have dug around the internet for a bit and haven't been able to find anything. When I try to run ...
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Suppress Warnings

I wish to know how to suppress the following warning obtained on qiskit when I try to add two different types of noise to a qubit ...
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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-...
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Can I run Cirq on IBMQ?

Google's quantum computer is not yet available for the public. Is it possible to run Cirq on IBM's quantum computers, instead of Qiskit? And if so, how can I do it? Thank you!
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Syndrome showing unexpected results for the [5,1,3] QEC code in qiskit

I have used the encoding procedure mentioned on page 35 of https://arxiv.org/pdf/quant-ph/9705052.pdf for the [5,1,3] code and then built the circuit for measuring the stabilizers (XZZXI, IXZZX, XIXZZ,...
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1answer
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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 ...
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1answer
107 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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1answer
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An effective way to submit all the jobs for VQE/QAOA at a time to an IBMQ machine?

In Qiskit, I am solving a VRP for 5 nodes and it creates 20 variables for a QUBO. It runs in a 65 qubit machines (any machine below that many fails). Now, in such a typical solvers for optimization (...
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2answers
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How can I run a job as offline on real hardware?

Can I run circuits on real hardware as offline? I mean that a job with 100 circuits may take a long time and I want to shot down my laptop in running time. In the meantime, can the real hardware run ...
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2answers
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How can i run a quantum circuit with parameterized gates many times on quantum experience?

I want to run a quantum circuit many times on real hardware so that this circuit has some of the parameters that I must change them each time (some of the angles of gates must change each time). how ...
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qasm_simulator generating identical results repeatedly

I wish to run a very simple circuit on the qasm_simulator backend. My circuit is ...
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2answers
50 views

How to realize Su-Schrieffer-Heeger model in Qiskit

This is a very specific question, which I try to implement a simple dimerized tight-binding Hamiltonian on qiskit. The model is one dimensional, and defined as $$ H = \sum_{\langle i,j\rangle} t_{ij} ...
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1answer
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Noise model for 3 Qubit $|GHZ \rangle$ state measurement circuit

I found this example code in Qiskit documentation. Does this code signify that it is simulating noise as per the IBM Valencia quantum chip. If yes, what kinds of noise does it simulate? I executed the ...
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1answer
32 views

ClassicalRegister gives out just one line instead of two

Why do we have just one line here in c0 and not 2?
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2answers
55 views

How to run VQE experiments on IBMQ Backends?

The VQE.run method only takes a quantum_instance of type QuantumInstance or BaseBackend and ...
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1answer
65 views

Why is circuit inverse not working for EfficientSU2?

For some reason I get the following error when attempting to find the inverse of the EfficientSU2 VQE variational form: TypeError: 'NoneType' object is not ...
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Report measurement components for a given Hamiltonian measurement

I was wondering if there is a possibility to report measurement components when reporting the final expectation values of a qubit operator. For example, if we look at a simple Hydrogen molecule ...
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1answer
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IF statement in OpenQASM on IBM Quantum Experience

This is a simple circuit introduced in Moran's book "Mastering Quantum Computing with IBM QX" to demonstrate how if works in OpenQASM: ...
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1answer
49 views

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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1answer
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Qiskit: Error when importing libraries for ADMM optimizer

I would like to try and ADMM optimizer as shown in Qiskit Tutorial in Quantum Lab. Firstly, I imported necessary libraries (copy/paste from the Tutorial): ...
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1answer
77 views

How to perform a time evolution of a quantum state with Qiskit Aqua?

How can we perform a time evolution of a quantum state for a given Hamiltonian with qiskit Aqua operator flow? I'm interested in it due to its higher efficiency.
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Can I get the job variable from the job_id?

Suppose I run the following code: job = execute(qc, backend = backend, shots = 1024, optimization_level = 0) Then the job takes a long time to run. We know that ...
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1answer
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Why does job appear to be stuck in queue on IBMQ backend?

I have submitted a batch of circuits to ibmq_vigo using the IBMQJobManager and the batch is correctly split properly into ...

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