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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Adding team to our IBM Quantum Experience account

I have an account and API token on IBM Quantum Experience (https://quantum-computing.ibm.com/) I would like to add team members to the account, so that everyone can use it without sharing login ...
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96 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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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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411 views

Measuring Coherence Length for T1 and T2 values with IBMQ Experience

So I'm currently working on a little program to measure how long the coherence time of a qubit is. Basically the idea is to initialise a qubit with a X or H gate then stick in a varying amount of ...
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89 views

Bell State 11 not working for parity curve

I am currently writing a script to automate the creation of parity curves for a 2 qubit bell state and then calculate fidelity and proving entanglement from that (inspired by this paper). It was going ...
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122 views

Results from looped experiments on IBM Q different than individual experiments

I'm experiencing an issue while using Qiskit where the counts from a job return vastly different values when ran in a loop or as an array of circuits as opposed to single experiments when run by ...
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1answer
97 views

IBM Q devices' hardware/resource constraints

I tried to look for the resource constraints but so far haven't been able to find them. They are not present in the GitHub repository that usually provides the hardware information for the different ...
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91 views

Implementing a depolarizing channel for 2 qubits on IBM Q

I am trying to use IBM Q to perform the following depolarizing channel on a state of 2 qubits $\rho=|\psi \rangle \langle \psi |$: $$\rho \to (1-\lambda)\rho + \frac{\lambda}{4}I$$ This is within ...
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60 views

“503: Server Unavailable. Your server appears to be down. Try restarting it from the hub”. Help

This message is popping continuously for 2 days in my IBM Quantum lab. I have tried logging out and in again, restarting the browser, changing the internet connection, and changing the device but this ...
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1answer
117 views

How do I identify a VQE job run in real hardware?

I am running a VQEUCCFactory for H2 on a real hardware device. ...
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45 views

What is the actual precision of the IBM quantum computer?

In working with the IBM quantum computer, one can use for example the composer in order to build simple quantum algorithms. Essentially, one usually feeds a phase in order to affect one of the qubits. ...
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91 views

Transpiler fails after 1000 iterations

I'm transpiling a set of quantum circuits using ibmq_5_yorktown. However, as the number of circuits gets larger, it shows me the following error message: ...
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50 views

IBM QE - Parameters that differentiate the various backends

I'm doing a university thesis using IBM's quantum backends. In my analysis I am making some considerations on what differentiates one backend from another other than the number of qubits and quantum ...
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1answer
401 views

Qiskit issues with Apple Silicon?

Edit/summary: Everything below this first paragraph is my original question posted several days ago and involves a lot of speculating on a problem I knew less about at the time. The purpose of this ...
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59 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
152 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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35 views

How many cores and what processors are used in the cloud ibmq_qasm_simulator?

Cloud IBMQ simulator ibmq_qasm_simulator can process up to 32-qubit circuits quite fast. However, I could not find any information about the simulator backend properties, e.g. how many cores, what ...
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103 views

Difficulty in implementing Grover's Algorithm with large number of qubits

It seems IBM offers a 15 qubit quantum computer through their quantum experience program. However, upon a quick search through the literature, the largest implementation of Grover's algorithm I have ...
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536 views

Qiskit Python program cannot connect to QE API

I am just getting started with Qiskit and IBM Quantum Experience, so please forgive my newby question. I have a IBM Quantum Experience account and I generated an API token. I used the generated ...
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1answer
53 views

How to Implement a noisy identity gate on qiskit?

I can successfully implement the U gate (single qubit) on qiskit, but when I am trying for the identity operation it is not showing any differences with the ideal one .
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Does dedicated mode provide better results than fairshare in mid-circuit measurement?

I'm using a research account and I have a question about running circuits with (dedicated/priority mode) and without reservation (fair-share mode). From the documentation of dedicated mode, This (The ...
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41 views

How to do a POVM measurement of a quantum state in IBM's Quantum Composer?

I'm new to IBM, so I'm still figuring things out. I want to make a POVM measurement of a quantum state for state discrimination purposes. In other words I want a measurement that has three outcomes: A:...
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1answer
128 views

API error when trying to access IBM Quantum Computer using IBMQ API Token

I'm trying to write a code so that if the token exists then it loads the account or else it asks the user for the API token. Below is the code for reference: ...
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1answer
56 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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63 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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1answer
100 views

Why I am not getting approximate equiprobable states in the following circuit on IBM Q simulator?

I have the following circuit which consists of symmetric modules. I compiled the circuit in IBM Quantum experience backend - ibmq_qasm_simulator, 8192 shots. The result is not equiprobable. Why? Since ...
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34 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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109 views

Is it possible to simulate or replicate a cryptographic algorithm using Qiskit?

I would like to know if it is possible to recreate or simulate a cryptographic encryption algorithm like DES or AES using the quantum computing platform Qiskit from IBM?
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127 views

Running HHL tutorial on real backend

I tried to follow the HHL tutorial. Since the 8x8 problem is not realistically simulable (I stopped after a few minutes), I tried to make it run on another backend, starting on the easiest example: <...
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1answer
96 views

How call from IBM Q Experience (Jupyter Notebook) cplex

I have the latest version of cplex (12.9) installed on my computer. I use it very well with Jupyter notebook, but in IBM Q Experience, I did not get way to call it. IBM Q Experience warns me that the ...
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966 views

How to run quantum SVM algorithm from Qiskit in real IBM Quantum Computer using IBMQ?

I'm trying to run QSVM algorithm in IBMQ experience, want to run in one of those real quantum computers. ...
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428 views

How to measure a Bell inequality violation in IBM Q?

Note: Cross-posted on Physics SE. I made some circuit to prepare a 2 qubit state, but I am having trouble understanding how to measure Bell's inequality. I know the inequality is of the form $$|E(a,...
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2answers
78 views

Random accuracy using VQC and Iris dataset

Using the same seed (seed_simulator and seed_transpiler) I get different accuracy when running it several times. In Aqua library (from qiskit.aqua.algorithms import VQC) I solved it adding ...
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1answer
55 views

Trying to connect IBM Quantum to External API

Is it possible to connect a quantum computer to openlibary.org API? How do I find the public IP address to my quantum instance?
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34 views

Recover qubits used in an actual computation

How do I recover from a certain job_id in the IBM backends which qubits where used? I would be interested to know if for instance, in a batch of say 50 jobs, 25 of ...
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39 views

issues running a 32 qubit grover's algorithm

I have a 32 qubit grover's algoritm however whenever I run it on the simulator that IBM offers it always ouputs a probability of 1 on every single result. Is there a way to run circuits larger then 32 ...
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1answer
75 views

IBM quantum computer giving the wrong result?

This is the first time I am using the IBM quantum computer. I tried to run a circuit (see below the first picture) but the results I got don't match the theoretical results shown (see below the second ...
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29 views

IBM Quantum “Jobs” web page problem: “Tags” always missing

I tried to edit the tags and saved them, but the "Jobs" page displays empty tags always. Is that a bug? Did I do it incorrectly?
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1answer
81 views

How to create a unitary gate using normalized complex numbers in qiskit?

If I have a normalized $(\alpha,\beta)$ as $(0.24506+0.9633i,0.0046238+0.10943i)$ for a qubit $\left| \psi \right> = (\alpha_1 + i\alpha_2 ) \left|0\right> + (\beta_1 + i\beta_2 )\left|1\right&...
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1answer
83 views

Braket and Q# Simulators

I have implemented Shor's algorithm in Qiskit, and everything works as expected within the IBM Q experience for both the IBM qasm_simulator and real hardware. However, after I've implemented Shors in ...
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2answers
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82 views

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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65 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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38 views

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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39 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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48 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
123 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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49 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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1answer
173 views

How to obtain the density matrix using tomography in the real device?

I am trying to run the QFT algorithm for n=5 (n number of qubits). The number of experiments that it generates is bigger than the one allowed by the IBM devices (i.e. 75). Therefore, I have tried to ...
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1answer
105 views

How to get running time for each circuit executed on IBM's quantum processors in one round?

I want to execute multiple circuits in one round on IBM's backends, especially the 16-qubit one, to save time. For instance, ...