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).

95 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
5 votes
0 answers
108 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 ...
user avatar
4 votes
0 answers
94 views

Quantum State Tomography Implementation in IBMQ

I am working to understand quantum state tomography, specifically using the algorithm presented in PRL 108, 070502. This paper is referenced in IBMQ implementations of QST, both in old deprecated ...
user avatar
4 votes
1 answer
184 views

How can I run a VQE on one of IBMQ's Quantum Computers

I have implemented a VQE based on Qiskit's VQE function and want to run that on an actual quantum computer. My understanding was, that an IBMQ backend can be passed into the function as a Quantum ...
user avatar
  • 41
4 votes
0 answers
55 views

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 ...
user avatar
4 votes
0 answers
107 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 ...
user avatar
4 votes
0 answers
268 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 ...
user avatar
4 votes
0 answers
449 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 ...
user avatar
4 votes
0 answers
136 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 ...
user avatar
4 votes
0 answers
164 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 ...
user avatar
  • 303
3 votes
0 answers
61 views

Implementing Shor's algorithm on IBM Quantum Composer

I'm trying to recreate from this paper in the IBM Quantum Composer. However, this circuit isn't enough understandable for me to do so. I have tried to recreate the above circuit in the composer as ...
user avatar
3 votes
0 answers
55 views

Incorrect probabilities in IBMQ Mid-circuit measurements

I calculated the probabilities for two measurements using mid-circuit measurements feature in IBMQ by following circuit: ...
user avatar
3 votes
0 answers
52 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. ...
user avatar
3 votes
0 answers
106 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: ...
user avatar
  • 2,158
3 votes
0 answers
62 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 ...
user avatar
3 votes
0 answers
77 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 ...
user avatar
3 votes
1 answer
198 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 ...
user avatar
  • 57
3 votes
0 answers
38 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 ...
user avatar
  • 31
3 votes
1 answer
114 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 ...
user avatar
3 votes
0 answers
128 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 ...
user avatar
  • 31
3 votes
1 answer
115 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 ...
user avatar
3 votes
0 answers
463 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,...
user avatar
  • 303
3 votes
0 answers
573 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 ...
user avatar
2 votes
0 answers
89 views

Calculating the Inner Product using Quantum Phase Estimation

I'm following the method laid out in https://arxiv.org/abs/2011.03429 (Page 23 Equations 13-23) to calculate the inner product of two amplitude embedded vectors using Quantum Phase Estimation. I'm ...
user avatar
2 votes
0 answers
66 views

Eigenvalues and energy levels of 1D Heisenberg model using real Quantum Computers?

The 1D Quantum Heisenberg model is $$H_\textrm{Heisenberg} = -~J \sum_{\langle i\ j\rangle} \hat{S}_{i} \cdot \hat{S}_{j}$$ where each spin is an operator. For simple cases, for example, a system with ...
user avatar
  • 305
2 votes
0 answers
99 views

How can I add custom pulse gate to the Qiskit circuit?

I tried to make my pulse and get the pulse into the circuit. But it seems not working properly. The code and the result are below. Just change the 'x' to the 'h' (hadamard) with the same piecewise ...
user avatar
2 votes
0 answers
52 views

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 ...
user avatar
  • 2,158
2 votes
1 answer
125 views

how can we save a model using qiskit_machine_learning?

How can we save a trained model using Qiskit Machine Learning library? I've built a VQC classification model and once finished, I'd like to save the different models to be loaded later. There is a <...
user avatar
2 votes
0 answers
82 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:...
user avatar
  • 21
2 votes
0 answers
76 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 ...
user avatar
2 votes
1 answer
97 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.
user avatar
2 votes
0 answers
88 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 ...
user avatar
  • 76
2 votes
0 answers
78 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. ...
user avatar
2 votes
0 answers
38 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 ...
user avatar
  • 105
2 votes
0 answers
130 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?
user avatar
2 votes
0 answers
155 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: <...
user avatar
  • 116
2 votes
0 answers
140 views

Number of Shots always 1024/or nothing (IBM q experience)

I have been running some simple "Hello Quantum World" code and every time I try to run it on 4096 shots or 8192 shots, the results always show as if I ran the code on 1024 shots (or in the most recent ...
user avatar
2 votes
0 answers
1k 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. ...
user avatar
1 vote
1 answer
36 views

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 ...
user avatar
  • 19
1 vote
0 answers
21 views

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 ...
user avatar
1 vote
1 answer
67 views

How can I get IBM's API token?

I need an API token to use IBM's real hardware(greater than 5 qubits) in Qiskit, where can I find the price?
user avatar
  • 11
1 vote
0 answers
20 views

Sequential Circuits in IBMQ and Qiskit and generating a clock pulse

I am trying to implement the Peres Gate with Feedback from Feynmann Gate feeding back into the third input to Peres Gate. This sequence needs to be repeated. There is also a clock pulse that needs to ...
user avatar
1 vote
0 answers
51 views

How to formulate QUBO as summation quadratic and linear parts of K-graph coloring problem?

While trying to understand the graph coloring problem with VQE using the QUBO Formulation mentioned section "5.2 Graph Coloring". Mentioned article prepared the QUBO directly in to matrix ...
user avatar
  • 21
1 vote
0 answers
21 views

Getting different sets of plots for the teleportation algorithm in Composer and Lab

I tried recreating the quantum teleportation circuit (in the Qiskit Foundation Youtube Playlist) both in Lab and Composer and getting different plots for each. Here is circuit and histogram from ...
user avatar
1 vote
1 answer
140 views

'Internal error. Error code 9999' when running job on IBMQ

I'm trying to run a series of circuits in a job and I keep getting this error message which I haven't been able to find the meaning of anywhere in qiskit's documentation, online, etc. The job appears ...
user avatar
1 vote
0 answers
71 views

How can I get the results from simulating noise models?

I'm trying to run some simulations of my quantum circuits using qasm simulator. I first tried to import the noise data from a quantum device and then use that information on qasm. Here's part of my ...
user avatar
  • 2,158
1 vote
0 answers
47 views

Solving Particle in Box problem using Qiskit

I am new to quantum computing, I would like to ask how can I solve simple particle in box problem using qiskit which allows to compute the bound states in finite quantum well. Finite quantum well
user avatar
1 vote
2 answers
88 views

How to apply gates based on a random decision on the IBM quantum computer?

I want to run a circuit on an IBM quantum computer, and this circuit involves gates that are either applied or not based on a (classical) random decision. As a minimal example, imagine a circuit with ...
user avatar
  • 11
1 vote
1 answer
83 views

Measuring the accuracy of a circuit output?

I have created a circuit and got the output which matches the truth table but, I'm not understanding the measuring the circuit output in terms of the probabilities, power or error. This is the circuit ...
user avatar
1 vote
2 answers
139 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 ...
user avatar
1 vote
0 answers
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 ...
user avatar