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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29 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
38 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
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
52 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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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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1answer
36 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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2answers
42 views

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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1answer
46 views

Unable to instantiate provider for research account locally

When I run IBMQ.load_account(). I have the error information: ...
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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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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
24 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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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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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
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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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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2answers
53 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
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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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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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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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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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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2answers
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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
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
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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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
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
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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3answers
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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
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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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
87 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
33 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
108 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
26 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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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
50 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
80 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 ...
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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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0answers
40 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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222 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
104 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
64 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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