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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1answer
103 views

My Bloch sphere/ qsphere is appearing as an ellipse/oval

I tried to plot a Bloch vector. However, my Bloch sphere is appearing as an ellipse/oval instead of a circle. I am having the same issues with qsphere also. instead of ...
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23 views

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 at IBM Quantum Experience (IQX)

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
27 views

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
35 views

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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1answer
50 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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1answer
34 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
45 views

Unable to instantiate provider for research account locally

When I run IBMQ.load_account(). I have the error information: ...
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2answers
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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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2answers
38 views

What is the significance of transpiling time, validating time, in queue time and running time?

What is the significance of different transpiling time, validating time, in queue time, running time for the same circuit run on different quantum systems for same no. of shots in IBM Q experience? ...
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How to get the CNOT error rate between 2 qubits on a given IBMQ Backend?

How can the CNOT gate error between 2 qubits as shown on visual qubit coupling map on the IBMQ Dashboard be retrieved in Qiskit using the BackendProperties....
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2answers
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My IBMQ job hangs forever?

I am running a very simple script just to learn how to use IBMQ, but my job will hang indefinitely and I am forced to terminate it. ...
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1answer
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Why does job execution time vary significantly across different IBMQ Backends?

I have run a batch of a few thousand random 2-qubit QuantumCircuits on multiple different IBMQ Backends, and the execution times seem to significantly vary across ...
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1answer
42 views

Quadratic optimization in Qiskit: Error when QuadraticProgram with quadratic constraint converted to QUBO

I prepared a quadratic optimization task with binary and integer variables and linear and quadratic constraints. I fed it into QuadraticProgram in Qiskit. After ...
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40 views

What is the best way to use loop statements on a quantum computer?

I am interested in solving a time dependent linear partial differential equation of the form $Ax=b$ which, in classical computing, would amount to looping over solutions of $Ax=b$ where $b$ is updated ...
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1answer
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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 ...
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1answer
36 views

How to optimize my HHL algorithm on qiskit?

I am following this HHL tutorial to solve the $Ax=b$ problem and have been using the general (inefficient) approach with the BasicAer simulator that they describe in section 4a. I would now like to ...
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1answer
40 views

How can I use the quantum volume to design the scale of my experiment?

I am designing an experiment which involves solving a linear system of equations of the form $Ax=b$. To do this, I am using the HHL algorithm on the IBMQ system. My experiment is scalable such that ...
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2answers
37 views

Generate a random bit sequence of 512 bits [duplicate]

How can I generate a random bit sequence of 512 bits on IBM Q experience using 3 or 5 qubits? Putting a hadammard gate and measuring would only give me smaller bit sequence due to limitation in number ...
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1answer
26 views

Error associated with HTTPSConnectionPool

How can I solve this situation? I'm using the IBMQX2 chip. When I run my simulation some circuits are executed and the following WARNING message is displayed: ...
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2answers
37 views

How to execute many circuits on an IBMQ backend?

I attempted to execute a list of $3200$ QuantumCircuits in Qiskit, each with the max_shots ...
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2answers
64 views

quantum random number generator implementation in quantum lab

How can I generate and print a 32 bit sequence of 0s and 1s in Qiskit or IBM Q experience quantum lab using quantum random number generator implementation?
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1answer
42 views

Why running time of qasm simulator is significantly smaller in comparison with quantum machines?

I ran a 3-qubit measurement circuit on QASM simulator as well as on IBM Q Melbourne, Santiago and Vigo machines. The running time on the simulator is in few milliseconds (400-800) while in the case of ...
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39 views

What causes the random variations in the probabilities with respect to the theoretical values, in IBM and QASM simulators?

When I measure 2 and 3 qubits after putting H gate on all of them, there is a variation in probabilities of results in comparison with theoretical values (25% and 12.5%, respectively). This occurs on ...
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1answer
30 views

What is the significance of varying the number of shots while running a circuit in a quantum machine and qasm simulator?

what is the significance of varying the number of shots while running a circuit in a quantum machine and qasm simulator? Does more number of shots give better/accurate result? I am running a simple 2 ...
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1answer
244 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. ...
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1answer
25 views

Type object 'AllPairs' has no attribute 'params'

When I try QSVM over Iris data, it needs multiclass extension, but when I provide it, a following error is returned: ...
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1answer
115 views

How to do error mitigation on the ibmq_16_melbourne?

I'm trying to make a calibration matrix using CompleteMeasFitter as in here on IBMQ Melbourne, but I need to use all 15 qubits, which mean it has to run 32768 calibration circuit, far exceeding the 75 ...
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1answer
62 views

How can we only use 8192 shots for an experiment with 14 or more qubits?

Let's say you want to do an experiment with 14+ qubits. You apply some arbitrary unitary operator $U \in (\mathbb{C}^2)^{\otimes n} \times (\mathbb{C}^2)^{\otimes n}$ to the state $|\psi\rangle \in (...
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1answer
27 views

Error while running Qiskit code on real quantum hardware

I started to learn Qiskit, so sorry if my question is very basic. So far I used qasm_simulator or state_vectorsimulator, ...
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1answer
38 views

How do I compute the fidelity on the IBM Q using qiskit without the statevector simulator?

I want to compare the fidelity of a circuit implemented on IBMQ Santiago with the ideal circuit simulated using the statevector backend. Is there a way to do this? So far I have only seen examples ...
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1answer
24 views

Getting an error running a program in IBM Q Experience Quantum lab

Running the program in Quantum Lab, it shows error. I am looking for solution. Here is a code I run: ...
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1answer
21 views

Do I need to download Qiskit from IBM quantum experience?

Do I need to download Qiskit seperately or can I learn and write programs as well as practically view possible visualizatios in IBM quantum experiene itself?
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Need mathematical Calculation of input(T1,T2,f) and output(Readout Error)

I would like to know about the mathematical relations among T1, T2, frequency, readout error, and single-qubit error? This screenshot is from the ibmq-16 Melbourne excel data file.
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1answer
71 views

What is the difference between Qiskit execute and the IBMQJobManager?

I was researching how to submit multiple pulse schedules/circuits in the same job and came across 2 methods: Executing Experiments with qiskit.execute and ...
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1answer
39 views

IBMQFactory object has not attribute backends

I try to run simple circuit measurement program using Qiskit in Visual Code. I received this error: AttributeError: 'IBMQFactory' object has no attribute 'backend' ...
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1answer
24 views

Unable to retrieve result for Job Error during VQE simulation

I am attempting to run a VQE calculation on the 'ibmq_qasm_simulator'. The job is failing with a series of errors caused by: ...
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1answer
28 views

Queue disabled and HTTP 403 error

I have already visited this What does it mean to get 403 error when running a code on Qiskit? which did not help me fix my problem. I want to test the quantum circuit that I have designed using the ...
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1answer
59 views

VQE jobs do not appear in queue

I am trying to calculate the ground state energy of some simple molecules using 'MolecularGroundStateEnergy' tools in qiskit. When I run the calculations for very small molecules (e.g. H2, HeH+) the ...
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1answer
54 views

Implementing block of gates at different times in a same qiskit program

I am implementing an Ising chain over 8 qubits. It involves pair-wise CNOT between all the qubits. In the first time step, I am doing CNOTs between qubits 0 and 1, 2 and 3, 4 and 5, and 6 and 7. In ...
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1answer
97 views

Why are there such different UGate and U3Gate implementations in the Qiskit documentation?

The documentation for the new version Qiskit 0.20.0 states that: UGate is "Implemented using two X90 pulses on IBM Quantum systems: $U(θ,ϕ,λ)=RZ(ϕ−π/2)RX(π/2)RZ(π−θ)RX(π/2)RZ(λ−π/2)$" ...
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1answer
53 views

How can I solve the problem of optimisation the quantum computer?

I am trying to solve the problem of optimization (VRP) with genetic algorithm and quantum computing in the platform IBM Q Experience. But I am unable to advance on this. How can I do it? According to ...
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0answers
28 views

Tensored vs ordinary measurement mitigation runtime

My experiments show that the runtime of actually applying the measurement filter matrices to circuit execution results is much slower for tensored mitigation than ordinary mitigation. Tensored ...
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2answers
214 views

Mitigating the noise in a quantum circuit

I'm using Qiskit and I have a Quantum Circuit (say, circuit) that gives reasonable results when using the simulator, namely ...
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0answers
181 views

Problem with measurement error mitigation using VQE

I am attempting to mitigate measurement error while running on one of IBM's real devices and am doing so by passing CompleteMeasFitter into ...
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1answer
86 views

Existing measurement error mitigation

Does IBM compute a measurement error mitigation calibration matrix that can be accessed from its device properties or somewhere else? Or does the user have to do that every time?
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74 views

What are the differences between the IBM machines?

I'm quite new to this field, and have started sending jobs to IBM's quantum computers. I have access to around 11 locations. I can see that these have different numbers of qubits within them, and then ...
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3answers
145 views

Existence of multiple job monitor in qiskit

I can see in example code of qiskit, to implement job monitors on IBM Quantum machines, example uses any of the following ...
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2answers
49 views

Subroutines on IBM Q (ERROR_RUNNING_JOB returned)

I wrote following code in QASM editor on IBM Q web interface (note ccu1 is controlled-controlled U1 gate): ...
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2answers
269 views

Why IBM Quantum Experience is giving different results under ibmq_qasm_simulator and ibmq_16_melbourne?

I am trying to run following 6 qubit quantum circuit and I am getting different results under ibmq_qasm_simulator and ibmq_16_melbourne (both involving 8192 shots). What is the reason? ...

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