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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124 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
63 views

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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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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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
54 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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1answer
148 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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2answers
294 views

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 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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2answers
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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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1answer
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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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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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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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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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1answer
67 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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1answer
110 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
142 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
356 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
40 views

Do I need to download Qiskit from IBM Quantum Experience?

Do I need to download Qiskit separately or can I learn and write programs as well as practically view possible visualizations in IBM Quantum Experience itself?
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1answer
68 views

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
308 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
177 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
65 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
257 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
82 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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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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1answer
44 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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3answers
263 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
293 views

Qiskit error on get_backend()

Im trying to use IBM quantum machine instead of qiskit aer simulator with the following command: backend = IBMQ.get_backend('ibmq_16_melbourne', 'ibm-q') It's ...
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1answer
40 views

Dose Quantum threshold theorem apply to IBM Quantum Experience

According to Quantum threshold theorem, error rate can be arbitrarily low. But when I use IBM Quantum Experience to measure a simple $|+\rangle$, it gives result of $|1\rangle$ with probability of 52....
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1answer
185 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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1answer
66 views

Does Qiskit offer a stack of functions to generate and manipulate graph states?

I'm looking for a way to test graph state verification protocols on the IBM Q. Has anyone yet written code to generate a graph state on IBM Q and also generate its stabilizer generators given the ...
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103 views

Form and effect of the intrinsic Hamiltonian on the IBM machines

I want to understand the form of the intrinsic Hamiltonian of the IBM machines, such as ibmq_16_melbourne, and how this affects the data I get out when waiting ...
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1answer
106 views

IBMQ_Melbourne Readout error

I am trying to simulate an experiment on IBM's melbourne quantum computer and here are the results Qasm simulator : ibmq_16_melbourne: error why is there such high probability of unwanted states i....
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1answer
43 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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0answers
69 views

What is the buffer time between gates of the ibmq_essex in nanoseconds?

This is a question that I asked on Qiskit ignis section of slack, with a very interesting answer by A Kapila, but I also need to get a short answer in nanoseconds. I want to evaluate decoherence in ...
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230 views

The analogous IBM circuit representation for the quantum scheme

I am trying to implement a quantum scheme of sharing a secret via EPR states. Here is my initial state of 6 qubits \begin{equation} |\psi\rangle=\left(\dfrac{|0\rangle_1|0\rangle_2+ |1\rangle_1|1\...
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2answers
163 views

How to create the logical $|0_L\rangle$ state for the Steane's 7-qubit code?

I don't know how to prepare using Qiskit the following state in order to implement a Steane's 7-qubit code circuit (I omit the normalization factor): \begin{align*} |0_L\rangle =&|0000000\rangle+|...
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1answer
89 views

CSV files cut results short in ibm-q-experience?

I have noticed that the csv files exported for results don’t have the resolution to correctly describe the output states for larger sets of qubits. It looks like it only exports numbers up to 15 ...
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383 views

IBMQ / Qiskit slack links are broken [closed]

It appears the Slack links to IBMQ slack pages are broken (The link is no longer active). This is case for links on both Qiskit and IBMQ support pages. What is the best way to gain access to the Slack ...
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1answer
158 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
120 views

How to remove ancilla bits from results?

I have a circuit with 2 ancilla bits. I have only asked that the circuit measure the 4 other qubits, but the results keep including the ancilla bits. How to remove the ancilla bits from the results?
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2answers
91 views

How do you turn the CX gate upside down on ibm-q-experience?

I am learning how to make Grover's algorithm but the last cx gate needs to be the opposite way around. It always makes the top qubit the control, so how do you turn it around?
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1answer
464 views

Why after transpiling a Qiskit circuit we obtain a different result?

I am trying to obtain the correct circuit transpiled for the ibmq_london device, as I want to know what the real gates applied in the quantum computer are. I am implementing the QFT circuit for 5 ...
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1answer
84 views

What extra functionality is available to an IBM Q Network member over a regular IBM Q Experience user

I've been trying to figure out the extra functionality available to IBM Q Network members that are not available to normal ...
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1answer
572 views

Question About How Qiskit Reset Gate Affects Other Entangled Qubits

I am trying to understand how the reset gate in Qiskit affects qubits its entangled with. Consider the following circuit with qubits $q_0$ and $q_1$: Where circuit240 takes $|0\rangle$ to $a|0\rangle ...
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1answer
462 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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2answers
463 views

Why are IBM QE backend results different from the qasm simulator for a simple quantum circuit?

I have looked at other questions that ask pretty much the same thing such as this and from what I gathered the significant difference in simulation and actual results is due to decoherence and ...
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1answer
274 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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57 views

Post-selection in QASM

In some quantum algorithms (for example HHL or quantum machine learning algorithms) an ancilla qubit(s) is measured firstly and based on result of the measurement other qubit(s) are measured or not. ...
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2answers
181 views

Why is the number of solutions given in Qiskit textbook(Quantum Counting Algorithm) as N-M instead of M?

I'm following the Qiskit textbook for Quantum Counting. We have assumed $M$ as the number of states containing solutions throughout the algorithm but at last, $N-M$ has been taken as the solution. ...

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