Questions tagged [ibm-q-experience]
Use this tag for questions about IBM's quantum processors which are accessible online. DO NOT use this for questions about general Qiskit issues. As of July 2018, there are five processors on the IBM Q Experience: two 5-qubit processors, one 16-qubit processor and two 20-qubit processors (only available to hubs, partners, and members of the IBM Q network).
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What is maximum circuit depth and size IBM Q5 and Q16 could handle?
I'm trying to implement a couple of algorithms on ibmq_16_melbourne, so I need to know if this device is able to handle with depth and size of my current circuit or ...
3
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0answers
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How much variation is there in the results between each quantum computer on the IBMQ Quantum Experience system?
For example, if you ran the same program on the 'ibmqx2' and 'ibmqx4' computers, how much variance would there be between the results from both systems? There is the inherent presence of noise in each ...
3
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1answer
46 views
Consistent QISkit error: “All devices are currently unavailable”
I am attempting to run the following on a remote backend through QISkit:
...
4
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3answers
95 views
Why is there a difference between the simulation results and the actual quantum computer results?
I ran the Grover's Algorithm for 3 Qubits on the IBM Q platform (ibmqx4) and the results of the simulation and the actual computer differ a lot. The screenshots of the circuit and the results are ...
4
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1answer
62 views
Qiskit - How do we measure the same single qubit system multiple times while also getting the counts/results after each measurement?
I am able to apply multiple measurements (2) to the same qubit system. However, I would like to get the counts right after each measurement is executed. I realize that the counts should be the same ...
2
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1answer
36 views
Qiskit: 'per shot' result
Is there a way to access the results of measurements 'per shot' performed on a backend such as one of the real IBM machines?
I know it can generate a histogram from the cumulative data, but I was ...
1
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0answers
22 views
QE error: No handlers could be found for logger
When I run a QASM program on a QE simulator, I get this error.
No handlers could be found for logger
"IBMQuantumExperience.IBMQuantumExperience"
What ...
3
votes
1answer
106 views
Why can't I connect to an IBMQ device?
I was trying the qiskit Terra tutorial and it seems that the code provided to connect to an actual quantum computer doesn't run properly. With my API token generated and stored into the variable "...
8
votes
1answer
135 views
Submitting jobs to IBM devices without Python
Qiskit can be used to submit jobs to IBM devices using Python (or Swift and JavaScript). But what if I want to use a different language?
For example, suppose I have a specific circuit I want to run. ...
1
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0answers
57 views
Qiskit - Authorization Required error
When I use Qiskit to do quantum computing, I suffer from a big problem.
When running the code,it turns out to be:
...
3
votes
1answer
123 views
Why can't you run a teleportation circuit on an IBM Q device?
I'm studying teleportation circuits with this tutorial and just out of curiosity, why can't a teleportation circuit be run on an IBM Q device?
2
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1answer
59 views
Print circuit compiled on hardware?
I would like to see the compiled circuit as executed on a hardware.
Nominally, this sequence of commands should return the QASM circuit in the variable ran_qc, but ...
2
votes
1answer
226 views
Is it possible to expand/merge different circuits?
Suppose I have created a circuit composed of some registers with the usual
qc = QuantumCircuit(qr, cr)
where qr and ...
6
votes
0answers
85 views
How are Rigetti and IBM QX device parameters related to Kraus operators?
Rigetti reports the following parameters: (https://www.rigetti.com/qpu)
T1, T2* times
1-qubit gate fidelity (F1q)
2-qubit gate fidelity (F2q) and,
read-out fidelity (Fro)
IBM QX reports the ...
8
votes
2answers
190 views
Qubits specification on IBMQ devices
As it is shown here, CNOT gates between different qubits have different error rates. I have the following questions:
1) While defining a circuit on QISkit, does ...
2
votes
2answers
118 views
How to run algorithms on IBMQ via Qiskit-Aqua?
I am trying to run an optimization problem on IBMQ. Running the same code on QASM simulator works fine. However, changing only the backend name to IBMQX takes long time. I am aware of the queues ...
6
votes
1answer
158 views
Depolarizing channel implementation on IBM Q
Given a single qubit in the computational basis, $|\psi\rangle =\alpha |0\rangle + \beta|1\rangle$, the density matrix is $\rho=|\psi\rangle\langle\psi|=\begin{pmatrix} \alpha^2 & \alpha \beta^*\\
...
2
votes
0answers
171 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 ...
4
votes
1answer
96 views
How to deal with -LookupError: backend “ibmqx4” is not found?
I am using Jupyter notebook to write and running my qiskit codes (python 3.6)
and every time I encounter the message: LookupError: backend "ibmqx4" is not found, right now the ibmqx4 computer is not ...
6
votes
2answers
344 views
How can I get access to IBM Q 20 Tokyo and IBM Q 20 Austin?
How can I get access to IBM Q 20 Tokyo and IBM Q 20 Austin?
In the Q- experience site there is written that the access is for IBM clients only and in the profile there is a "promotional code" that ...
3
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2answers
356 views
5
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3answers
221 views
Is there something like GitHub for Quantum Programming?
I'm just learning about quantum computer but some of it has been available for people to research & practice so I'd like to study it myself. The only kind of quantum computing I found so far is ...
5
votes
1answer
127 views
What is the purpose of the TDG gate in QISKit?
The QISKIT documentation doesn't explain what a TDG gate does and I can't find it anywhere else online.
5
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1answer
384 views
Phase-Shift Gate in Qiskit
How to implement the phase shift gate in qiskit or ibmq?
Phase Shift Gate : $$\begin{pmatrix}e^{ia} && 0 \\ 0 && e^{ia}\end{pmatrix} = e^{ia}I$$
5
votes
2answers
320 views
Controlled-U operation in IBMQ
Suppose we have any matrix in $\mathrm U(2)$ and we need to construct a Controlled-$U$ operation with the $H,T,S$ gates. Then I am aware of the construction given in N&C of decomposing $U$ into $e^...
8
votes
2answers
377 views
Quantum algorithm for linear systems of equations (HHL09): Step 2 - Preparation of the initial states $|\Psi_0\rangle$ and $|b\rangle$
This is a continuation of Quantum algorithm for linear systems of equations (HHL09): Step 2 - What is $|\Psi_0\rangle$?
In the paper: Quantum algorithm for linear systems of equations (Harrow, ...
5
votes
1answer
92 views
How to implement a random selection of one of the 3 qubits on the IBM Q (composer)?
I would like to implement a quantum program on the IBM Composer with following characteristics:
The output is the observed value of 3 qubits
Only one of the 3 qubits should be observed as $1$, the 2 ...
6
votes
1answer
172 views
How to implement a Square root of Swap gate that swaps 2n-qubits on the IBM Q (composer)?
I am looking for an implementation using the quantum gates provided by the IBM composer of the following quantum function:
input $2n$ qubits
output $2n$ qubits wherein $50\%$ of the cases the state ...
5
votes
2answers
555 views
How to implement the 4 Bell states on the IBM Q (composer)?
I would like to simulate the 4 "Bell States" on the IBM composer?
How can I best implement those 4 Bell states using the existing set of gates ?
Here below you see the definition of the 4 Bell ...
7
votes
2answers
208 views
Practical Implementations of QECCs in IBM Q Experience
I am learning how to program the IBM Q Experience quantum computers in order to learn more about how does it work and in order to perform some experiments in it. By doing so I was wondering what are ...
9
votes
3answers
634 views
How to implement the “Square root of Swap gate” on the IBM Q (composer)?
I would like to simulate a quantum algorithm where one of the steps is "Square root of Swap gate" between 2 qubits.
How can I implement this step using the IBM composer?
10
votes
2answers
601 views
Implementation of the oracle of Grover's algorithm on IBM Q using three qubits
I am trying to get used to IBM Q by implementing three qubits Grover's algorithm but having difficulty to implement the oracle.
Could you show how to do that or suggest some good resources to get ...
10
votes
1answer
380 views
How can a controlled-Ry be made from CNOTs and rotations?
I want to be able to applied controlled versions of the $R_y$ gate (rotation around the Y axis) for real devices on the IBM Q Experience. Can this be done? If so, how?
8
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1answer
314 views
How to delete pending jobs on IBM Quantum Computer to retrieve units?
I am trying to run some code using qiskit, but I get the error message, that I have run out of necessary Experiment Units. I ...
13
votes
3answers
688 views
What would a very simple quantum program look like?
After reading the "first programmable quantum photonic chip". I was wondering just what software for a computer that uses quantum entanglement would be like.
Is there any example of code for specific ...
