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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Why after breaking the entanglement does the phase disk in the second qbit not match the result?

I am new in IBM composer quantum and I have a doubt. I have the next circuit After reinitializing q0 and reading it. (breaking entanglement) The phase disk for qubit q1 says that 100% is 0, but the ...
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3 votes
1 answer
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Qiskit Runtime: What are the units of job.result().time_taken? Seconds, milli-seconds, micro-seconds?

job = execute(qwalk_circuit, backend='ibmq_16_melbourne', shots=1000) results = job.result() time = job.result().time_taken What are the units of time? And where ...
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How to run PegasosQSVC on IBMQ backend

I'm trying to run a PegasosQSVC on one of the IBMQ Quantum computers though the code just throws errors once we reach the training phase ie: PegasosQSVC().fit ...
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Copying a reduced noise model from an IBM device

I need to use the noise model coming from a large IBM device. Nonetheless, I do not need to use the whole Noise Model. I only need the information of let's say qubits [10:15] and [20:25]. That would ...
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Grover Adaptive Search in Qiskit - why ancilla qubit is not used?

I am trying to solve some QUBO tasks with Grover Adaptive Search ("GAS"). For testing purposes, I use a simple task with quadratic part $$ A = \begin{pmatrix}0 & -0.5 \\ -0.5 & 0\end{...
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How to monitor a qiskit neural network on IBM Cloud?

I know qiskit offers the job_monitor function. However it only allows monitoring a BaseJob, for instance the one outputted from ...
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1 answer
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Where are the multi-qubit openpulse computers?

As the question says, I'm looking to run some pulse schedules on quantum computers. Right now, I'm really only able to find ibmq_armonk (from IBM) to be an openpulse computer that I am able to use. I'...
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1 vote
0 answers
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How to send another job to a device before finishing the last job?

Is there any way to create a for loop that would send a few jobs to run on a quantum computer simultaneously? I tried: ...
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1 vote
1 answer
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What is "time in system" for a given job and how to retrieve?

I noticed that there is "time in system" for each job. For example: I was wondering what does this mean? I am guessing this means the time of the first shot starts on the quantum devices ...
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1 answer
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How to get statevector of qubits after running quantum circuits on IBMQ real hardware to calculate the fidelity of all qubits individually?

Is it possible to get the statevector while running quantum circuits on IBMQ real hardware? If getting the statevector is not possible can I still calculate the fidelity of a qubit somehow?. What I ...
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IBM Quantum Lab - Server unavailable or unreachable. Would you like to restart?

In the following circuit, I want to perform tomography on the qubits 0,1,2,3 after qubits 4,5,6,7,8,9 are measured. I run the circuit using with measurement gates on qubits 4,5,6,7,8,9 with the ...
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1 vote
2 answers
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How to deterministically add two integers on a quantum computer

I am new to the Quantum Computer world. I understand the basics of Quantum mechanics and I have watched a few lectures on Quantum computers, Quantum gates and played a bit on IBM QC. As far as I ...
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1 vote
2 answers
62 views

which device had the best Average coherence time?

These are the IBM backend overview, do: Avg.T1/T2: here stand for the Average decoherence time or coherence time?
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2 votes
1 answer
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How can I know the number of qubits used in a job in qiskit?

How can I know the number of qubits used in a job in qiskit? I can always do something like ...
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1 answer
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Hadamard on first qubit for two qubit state doesn't output what it should on Qiskit

I'm using python qiskit==0.36.2. The following code: ...
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2 votes
1 answer
61 views

How can I write if conditions on quantum registers using qiskit

There is a quantum register measured to state $\left|00\right> $ How can i write a code to check weather the first qubit in measured state is 1 or zero and if 1 do some operations or if 0 do other ...
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2 answers
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QV circuits fail to execute in real devices

I tried to change a little the code here for running the quantum volume circuits in real devices. My code is ...
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0 answers
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Error with optimizer in torch-train program

I would like to train hybrid QNN models with the torch-train program of IBMQ but I have the following error: Object of type Adam is not JSON serializable. What optimizer can we use with "torch-...
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1 vote
1 answer
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Can someone explain to me what is T gate and tdg like im five?

I'm newbie to quantum computing, i read about these two gates on IBM quantum computing docs, but I can't seem to understand what is t-gate and tdg or t-dagger, can someone give me a simple explanation ...
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3 votes
1 answer
135 views

How to estimate Qiskit circuit runtime before sending to run on IBM real quantum device?

Qiskit, I tried to estimate circuit runtime using gate_length from Backend.properties() but its accuracy is very low (real system is 3.5 seconds, estimation is 0.00002 seconds). So, are there other ...
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3 votes
1 answer
112 views

Performance metrics in QSVM

I have implemented QSVM on breast cancer dataset using link: "https://qiskit.org/documentation/stable/0.24/tutorials/machine_learning/01_qsvm_classification.html" but unable to compute other ...
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1 vote
1 answer
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Converting data into a SHA256 hash using Qiskit quantum computer

I was wondering how can we convert data into a hash using Qiskit quantum computer? e.g, this code below will generate a SHA256 hash based on random data. ...
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0 answers
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Is there a way to connect a IBM quantum lab code to an Unreal Engine project?

I would like to know whether someone tried this before, I'm interested in be able to connect this tools. I know that Unreal Engine has a plugin to program with python, that all I know. I'll really ...
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1 answer
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What is $j$ in the state $|\psi\rangle=\sqrt{(1-p)}|0\rangle + e^{j\phi}\sqrt{p}|1\rangle$?

What is the j in the single qubit state equation in the Quantum Phase section? https://quantum-computing.ibm.com/composer/docs/iqx/guide/introducing-qubit-phase it's not defined in the page itself (...
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2 votes
2 answers
56 views

Can I Convert a Qubit in complex form to polar form?

Let's say I have a qubit $$\left| \psi \right> = (\alpha_1 + i\alpha_2 ) \left|0\right> + (\beta_1 + i\beta_2 )\left|1\right>$$ Can I able convert this to polar form $$|\psi \rangle = \cos\...
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6 votes
4 answers
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How are IBM's 127 qubits more potent than the 5760 qubits D-Wave - Advantage_system6.1?

Hi I'm a newbie in quantum computing recently I had a look at the AWS braket and I've seen they had a machine called D-Wave - Advantage_system6.1 that has 5760 qubits but when I googled the highest ...
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2 votes
1 answer
45 views

Iterative quantum phase estimation - real device

I'm trying to implement the iterative quantum phase estimation on a real (IBM) quantum computer. I'm using the code below. When I run this code on a simulator the results are the expected ones, but ...
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3 votes
2 answers
75 views

Understanding the output of a Deutsch-Jozsa circuit

I'm looking at the Deustch-Jozsa algorithm. While reading this Qiskit tutorial. I didn't understand what the presented result in plot mean. That is, why the output 1111 means a balanced function? What ...
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1 answer
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Qiskit library.gaussian() does not accept parametric expression

I'm trying to build a gaussian pulse in qiskit where I keep the amplitude as a parameter but for the followig code ...
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1 vote
1 answer
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Generating a random 32-byte hex integer using Qiskit

Hello I posted here yesterday about generating random 16 digits using Qiskit, and a gentle guy helped me but how about a string? How can I generate random 256 bit key in hex format in a superposition ...
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1 vote
2 answers
67 views

How do I use the quantum searching algorithm to loop search through a datafile in qiskit?

I have a localhost index.html has a table contains names and address and balances etc... also there is a search bar on the home page to go through the pages, the interesting thing is, there is loooot ...
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2 votes
1 answer
104 views

Question about mock backends!

I recently learned about the mock backends or the fake backends provided by Qiskit and I was wondering, do they behave the same way IBMQ systems backends like (ibmq_brooklyn)? also, can I depend on ...
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2 votes
1 answer
566 views

How does a quantum computer find the correct password faster than classical computers using brute-force?

I didn't get this part right! For example, we have an online box with a 16-digit password, and we don't know what the password is! How can a quantum computer find the correct password faster than ...
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2 votes
2 answers
77 views

IBM Quantum Experiment CNOT

I have a beginner question regarding CNOT-Gates on IBM Quantum. Assuming the following simple circuit: ...
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1 answer
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How to run Quantum Instance into ibmq_qasm_simulator

I have tried to run Shor's algorithm using IBM high performance simulator. I am currently using QuantumInstance to factorize a number. The code is provided below: <...
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0 answers
55 views

ValueError: setting an array element with a sequence for qiskit

I am trying to implement Quantum Kernel Ridge Regression (replacing the classical kernel with quantum kernel) in qiskit. The shape of my input x is (7165 x 529) and due to reshaping errors, I added an ...
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1 vote
1 answer
53 views

Circuit Construction using IBM Quantum Composer

I am trying to create the following circuit in IBM Quantum Composer but I cannot add the last H gate correctly. It falls in the wrong place. Why?
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1 vote
1 answer
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Design Digital logic circuit in IBM quantum lab

This is my first question here. I've started doing research in quantum computing. In Digital Logic circuits, there are many circuits (like parity generator, checker, demux etc.) that can be ...
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0 answers
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How can I use an if function on the IBMQ experience

I have seen elsewhere on here that the quantum simulators allow boolean functions (I'm using the if function) but the actual quantum computer doesn't currently support if functions; is there a ...
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-1 votes
1 answer
52 views

Quantum ripple-carry adder construction

I am attempting to build a 2-bit ripple-carry adder, using IBM Quantum Experience composer, but I'm confused on how to construct the carry transpose that is shown at the bottom?
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1 vote
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What is the relation between the database made up of N elements and the index made up of a string length n in the query model?

I am working on a circuit model that contains a blackbox (query) and do not understand the relationship between what is in the black box and the way we get out the value of the element we index. The ...
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1 vote
1 answer
99 views

How to access a qiskit runtime job and query time_taken?

I am trying to execute qiskit runtime jobs on simulators and real machines and I would like to extract information about the time taken to execute each runtime job. Since using python ...
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0 votes
1 answer
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Decompose native gates using Qiskit framework [closed]

I've read the papers about quantum hardware. These papers [1] [2] mention that native gates of IBM quantum computer are $R_x(\pi/2), R_z(\lambda)\space and \space CR \space (Cross Resonance)$ My ...
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2 votes
1 answer
62 views

Is pennylane free?

I was going through the basics of pennylane. I am able to understand that it is used for quantum neural networks. I am not sure whether it is using paid cloud computer or simulator of xandu or ibmq? ...
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2 votes
1 answer
29 views

Qubit State (theta,phi) Dependence on the Readout Error

Do the readout errors on the publicly available IBM quantum computers have any dependency on the state being measured? That is, if we are measuring a qubit in the state $\cos({\theta/2}) |0> + e^{i\...
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2 votes
1 answer
53 views

Why does application of Hadamard gate on $|0\rangle$ inverts the state on bloch sphere?

I am trying to understand what is the affect of Hadamard gate on qubit. So far, I understand that applying $H$ gate on qubit, puts the qubit into superposition state where the probability of the qubit ...
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2 votes
1 answer
104 views

Duration of single qubit gate in IBM

how can we calculate the duration of single qubit gate using Qiskit in IBM? In other words if I have to insert a delay in the place of the single qubit gate, how would I know how much delay in ...
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3 votes
1 answer
56 views

What's the difference between depth and num_tensor_factor in qiskit

Now I'm studying about the quantum circuit in qiskit developed by IBM. The quantum circuit have a several method in itself like depth() and num_tensor_factor(). I don't know what is different between ...
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0 votes
1 answer
43 views

Unable to interpret output by qiskit

I have built a simple 2 qubit entanglement circuit and wanted to measure using a real quantum device. I ran the below command an dthe have an output that is not what I was expecting. qiskit.providers....
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Maximum depth of a circuit in IBM

Given Quantum Volume and number of qubits of a IBMQ device, what is the formula to calculate the maximum depth of the circuit that gives high fidelity? For example: Let us consider ...
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