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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210 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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38 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
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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
58 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
98 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
105 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
40 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
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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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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146 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
84 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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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
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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1answer
104 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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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
421 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
506 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
366 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
441 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
251 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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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
173 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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1answer
72 views

Time taken on IBM Q qasm_simulator vs real backend

Running the same quantum circuit (example picture below, I've tried similar circuits too), both on a simulator and real backend, I've found than the simulator is always faster (sometimes by order of ...
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1answer
52 views

Problem with comments and code rearranging in IBM Q web interface

I wrote some code in QASM in the IBM Q Experience web interface and then I added some comments. After that I saved the code and run it. However, the code was rearranged (for example some gates were ...
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1answer
154 views

Quantum error correction on IBM devices?

I'm wondering if the gate errors on any of the IBM devices are low enough so that we could use some error correcting codes which do not require too many qubits? (such as 5- or 7-qubit codes). Even ...
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379 views

How can I install the 'ibmq_qasm_simulator' backend?

I'm having trouble running the following cell: The system told me "The 'ibmq_qasm_simulator' backend is not installed in your system." I'm so confused. Is there a way I can install this backend in my ...
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1answer
149 views

Do all physical architectures for quantum computers use the same universal gate sets?

Now I have understood that physical implementation of quantum computer need a universal quantum gate set like Clifford+T to realize any unitary quantum gate. However, I don't know if it is all the ...
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2answers
72 views

How to stop optimization of a circuit during transpiling in web-interface of IBM Q?

I was playing with approximation of gates with Clifford+T group on IBM Q. Everything works well on simulator, however, when I tried to run my circuit on actual quantum processor, a transpiler ...
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1answer
48 views

Who cares about Transpiled Circuit Text? [duplicate]

At any result of a job in this last version of the Circuit Composer, at the OpenQasm tab inside the Circuit Diagram, I am unable to use the tradicional copy or ctrl-c to get the transpiled circuit ...
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1answer
267 views

How to not optimize the quantum gates in a qiskit circuit when running it in the real device?

I have been trying to run two circuits in the ibmq_london device, the one resulting of applying one X gate on qubit $0$ and the one that applies two X gates. I know that applying two X gates is the ...
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1answer
49 views

Grover oracle result: vectors (0,1) & (0,1) => two Hadamards => product of two H results => CZ = (.5, .-5, -.5, -.5)

According to the Grover's algorithm section in the IBM Quantum Experience, if I have two qubits in the "one" state (vectors (0,1) and (0,1)), and I apply a Hadamard gate to each of them, and then ...
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1answer
118 views

Names of IBM Q backends

IBM Q backends have many different names, see for example this link. We have for example processors called Melbourne, Tokyo, Armonk etc. I am curious where these names come from? For example, I know ...
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1answer
230 views

Problem with code in 'Learning quantum computation using qiskit

I've started learning quantum computing using 'Learn quantum computation using qiskit', and I've stumbled upon what I think is a bug in the code in chapter 1.3: Representing Qubit States when I ...
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1answer
74 views

IBM Q Experience - Can it be used draw out ML inferences? [closed]

Are there Quantum-enhanced Machine Learning algorithms that can be implemented via Qiskit in IBM Q Experience and obtain valuable inferences faster than their classical counterparts from datasets of ...
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1answer
50 views

Install qiskit in django project

I was wondering if it's possible to use qiskit inside a django project. I found some ways to install jupyter notebooks, but I am not sure what is happening with qiskit. Ideally I would like to import ...
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1answer
172 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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2answers
259 views

Moore's law for quantum computers

Moore's law states that performance of classical computers doubles every two years (later revised to 18 months) and a price for computing resources halves during same time period. Currently, it seems ...
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1answer
44 views

Conversion of python code on Machine learning to realise on quantum processor

I need to realise a Python code program on Qiskit. It works on fuzzy logic. How should I realise the same using quantum processors using Qiskit? Is there any support on realising Python code for Fuzzy ...
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1answer
96 views

How do IBM, D-Wave, etc. change phase physically?

How do IBM, D-Wave, etc. change phase physically? In real hardware?
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2answers
99 views

IBMQfactory._initialize_providers Error

After a successful first run without problems, I found that I cannot connect any longer. Code: ...
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1answer
104 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, ...
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1answer
52 views

Is it possible to build a quantum processor with connections among all qubits?

Current quantum processors have constrained connectivity among qubits. For example Starmon-5 processor by Quantum Inspire has only one qubit connected to others, effectively it looks like a star. The ...
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1answer
68 views

How to reduce unnecessary waiting time when using IBM's backend?

I'm working with a program, which needs iterations of quantum computation like this ...
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0answers
64 views

ibmq_qasm_simulator from IBMQ provider and qasm_simulator from Aer provider gives different results

I'm running an experiment first on qasm_simulator backend from Aer provider and the most frequent result is the correct one with ...
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2answers
51 views

Do I have to upgrade to personal computer or laptop computer in order to be able to use the IBM Quantum Experience website or run code locally?

I currently have a tablet I don't have a desktop or laptop to access the IBM Quantum Experience. Do I have to upgrade to personal computer or laptop computer in order to be able to use the website or ...
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2answers
350 views

How to write decent code for oracle in Qiskit without custom circuit or long truth table?

I am now practising using Qiskit. The example of Grover's algorithm in tutorials suggests using logical expression, truth table or circuit to construct the oracle. In most textbooks on quantum ...
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1answer
70 views

How can I find the most suitable IBMQ provider for my location? [duplicate]

I have been trying to run my code on IBM's quantum computers, so I used the following commands to associate a quantum computer to the component qcomp: ...
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3answers
264 views

Trying to get a provider from IBMQ but get 'No provider matches the criteria.'

I have created a circuit and then run the following: provider = IBMQ.get_provider('ibm-q') And this is what I get: ...

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