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Questions tagged [qiskit]

Quantum Software Development Kit for writing quantum computing experiments, programs, and applications. If appropriate, also use the [programming] tag.

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3
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1answer
16 views

Why is the order reversed on measurement?

Why is the order reversed on measurement? ...
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1answer
18 views

qiskit - Creating your own ExperimentResultData object

Could someone guide me on how to create my own qiskit.result.models.ExperimentResultData object? I would simply like to create an object with some self-created dict ...
1
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1answer
42 views

Strange circuit with multi-qubit 'unitary' gates after transpiler with optimization level 3

Recently, I used the transpile() function with the level 3 preset pass manager to compile a very long and complex circuit on a real device coupling map. I was curious to see how much the depth of the ...
2
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1answer
40 views

How to decompose a unitary matrix to the standard gate set?

I have read some of the other decomposition questions here however still don't understand how to do it manually. The matrix I wish to decompose is the following for 2 qubits: $M=\frac{1}{\sqrt2}\...
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0answers
22 views

In Grover, how to implement oracle and amplification using Qiskit?

I found some examples of implementing the oracle when the marked state is $|000\rangle$. But how can we know what gate we should use inside of the oracle? Besides, for the part implementation, the ...
2
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1answer
26 views
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0answers
31 views

How to solve problems from Qiskit tutorial's chapter on Grover's algorithm?

I just read the Qiskit tutorial about Grover's algorithm. In the example, I don't understand how they determine the amplification circuit part as a bunch of $X$, $CCZ$ and $Z$ gates? How to ...
0
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1answer
39 views

How does one get the attributes of a circuit from its DAG in qiskit?

I have the following code, which runs properly. ...
-1
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1answer
61 views

Problem in installing Qiskit

When I try to install Qiskit using Pip install Qiskit I get the error as shown in the attached snapshot. Any help will be highly appreciated.
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0answers
32 views

Problems in installing Qiskit [duplicate]

I am trying to install Qiskit in ubuntu 16.04. I have installed Anaconda. When i do 'conda list' in my environment I see the packages, the photo of which I am attaching with this post. But when I ...
2
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1answer
49 views

Quantum pricing of financial derivatives (call option) in Qiskit Aqua

In finance, a European call gives the buyer the right to buy some underlying asset such as a stock at some pre-determined strike price at a specific expiration date. The Black-Scholes equation is a ...
-1
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2answers
58 views

How do you pass input to a circuit? [on hold]

I've implemented Grover's search algorithm in qiskit, and I'd like to pass in an input to run through the circuit. How is that done?
1
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1answer
82 views

Trying to make irreversable operation in the quantum circuit

I want to make a 2 qubit circuit such that the non-unitary program will transform the regular basis in the way that: $|0 0\rangle \to |00\rangle$ $|0 1\rangle \to |01\rangle$ $|10\rangle \to |01\...
0
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1answer
35 views

What is the time zone for the time returned by backend.properties()?

For example, backend.properties() returns following: ...
1
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2answers
67 views

How do I find out which stable Python version Qiskit will be compatible to?

Recently I've got a new machine and had to start over again (Qiskit installation). As this was not my first time in creating a Qiskit environment on Anaconda, I was able to work out the errors. ...
1
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0answers
52 views

Many jobs hanging after creating

I am running a VQE calculation running from a cluster using nohup. However, some of my jobs keep hanging with 'creating' and therefore my VQE is not converging/not working. However, at the same time,...
2
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1answer
66 views

What is the location of the Qiskit config file?

I'm trying to follow the instructions here https://qiskit.org/documentation/getting_started.html. It says The default backend for qiskit.visualization.circuit_drawer() or QuantumCircuit.draw() is ...
2
votes
1answer
137 views

In qiskit, doing 2 subsequent measurements of a Hadamard gate on the same qubit always gives 0 on the 2nd one

When I execute the following circuit, I expect that in both classical registers, the content is identical. ...
2
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0answers
72 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 ...
1
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1answer
34 views

Attribute error in Qiskit

Tried executing plot_histogram(result.get_counts(circuit)) where result has the job result and circuit is the Quantum circuit But an attribute error hits every ...
2
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1answer
52 views

Error on loading account with qiskit: “TypeError: __init__() missing 1 required positional argument: 'url'”

We are using an open account. We can not load the account even when we use the code on new notebook. The error message is: ...
4
votes
1answer
104 views

How to parallelly run a quantum circuit on IBMQ?

I am trying to implement the following circuit and my code is The above circuit has size 5 and depth 3. My question is, how can I run the circuit parallelly. I mean, the gate ...
1
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0answers
35 views

Suggestions for hybrid factoring algorithm on DWave and Qiskit

I was wondering if the multi-prime factoring problem can be solved in a hybrid approach using DWave (to factor) and Shor's algorithm (in Qiskit)? Please let me know your thoughts. Thanks!
4
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1answer
60 views

How to selectively apply noise in Qiskit simulations?

In Qiskit it is possible to specify noise models to apply to simulations. This allows noise to be defined for certain operations, like measurement or each type of gate. Is it also possible to change ...
2
votes
2answers
114 views

How to prepare a specific initial state of three qubits?

I would like to prepare the following initial state for variational quantum algorithms: $$ \sin\theta_1 \sin\theta_2 \sin\theta_3 |000\rangle + \sin\theta_1 \sin\theta_2 \cos\theta_3 |001\rangle + \...
2
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1answer
47 views

Implementing noise model in Qiskit using arbitrary basis gates

Consider the simplified code below. The code creates a quantum circuit and a simplified noise model. When I try to simulate this circuit using the noise model I get error message that the simulation ...
4
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1answer
66 views

Resources in Spanish to start learning quantum computing and quantum programming (Qiskit)

I’m starting an engineering degree in computer systems and I’m starting to get really interested in quantum computing. First of all, I don’t know where or how to start and I would really like to learn ...
3
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0answers
48 views

`execute()` hangs and eats memory

Used memory-profiler to check why I get memory spikes in what I though were small circuits. The circuit itself is constructed using ...
2
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1answer
63 views

How many ancilla qubits to use with Multiple-Control Toffoli (mct) gate in Qiskit?

The Multiple-Control Toffoli (mct) gate takes as input: 1. a register containing the control qubits, 2. the target qubits and 3. a register containing ancilla qubits. I don't know how many ...
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0answers
55 views

'ERROR: QasmSimulator: Circuit cannot be run using available methods.'

I used the following code. Can anyone say what that error is about? ...
2
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1answer
60 views

When I load a saved account, I get a license-agreement error (links to old website)

I cobbled together a few programs with Qiskit several months back which worked fine on both the BasicAer simulators and the actual IBMQ computers. However, when I tried to revisit them recently, ...
3
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0answers
50 views

Is there a way to develop a multiple controlled X or Z gate on Qiskit without using ancillary qubits?

I know for instance I can derive a cccX gate using 2 Toffoli gates on 5 qubit wire or ccccX with 3 Toffoli gates and 7 qubits and so on. you will notice the depth is increasing as the number of ...
-3
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1answer
119 views

Exploring quantum computing with Qiskit [closed]

I'm prepared to explore quantum computing which is completely new to me. Searching for a while on the Internet, I found IBM Qiskit which is an Open Source software necessitated for Quantum Computing. ...
3
votes
1answer
225 views

What is a “barrier” in Qiskit circuits?

I just started studying IBM Qiskit, and cannot find details about the barrier method on the QuantumCircuit class. It is shown in the circuit drawing, but I never heard about it after reading quantum ...
2
votes
1answer
44 views

n-qubit circuit run with > n qubits?

I was reading the Qiskit tutorial on circuit properties and there is a section (Unitary Factors) which states that even though an example circuit is made of 12 qubits, it may not need 12 qubits to run....
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1answer
62 views

What is ''524 Server Error''?

When running my code, sometimes I find this 524 Server Error: Origin Time-out for url and then my code stop. The error is in ...
0
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1answer
33 views

Quantum Circuit Properties typo (documentation bug?)

Just to report that the notebook "Quantum Circuit Properties" under the Tutorial uses a circuit named qc2 but afterwards the sample code still uses the ...
3
votes
3answers
107 views

How to plot custom gate labels in Qiskit?

How can I create a custom gate in qiskit that is plotted using latex formatting (or another type of formatting)? For example the following code generates a circuit diagram ...
4
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0answers
201 views

Is it possible to run a general implementation Shor's algorithm on a real IBM quantum computer at least for N = 15?

I need to make a general implementation of Shor's algorithm that factors, at least, N = 15. I have been able to perform an implementation that works in simulators, with ProjectQ, but when running it ...
2
votes
1answer
72 views

QAOA Maxcut for larger qubits

I am using QAOA to solve maxcut problem. It takes a very long time to simulate 10 qubits and I never get the results. Is there a way to simulate faster for larger qubit? Here is my code ...
1
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3answers
98 views

How many classical registers are there on (IBM) quantum computers?

I have a circuit where I only use 3 qubits but need to utilize hundreds of classical registers. My questions are: what is the maximum number of classical bits on the current IBM Qs? What is the ...
2
votes
2answers
101 views

How to unpickle a Result object returned by an IBMQ experiment?

I have executed an experiment using IBMQ and receive a Result object. I am writing the ASCII repr of the result with f.write(res)...
2
votes
1answer
64 views

How can we construct a square root of NOT gate in Qiskit and IBMQ circuit composer using universal gates?

I have tried it with decomposing controlled S then conjugating with H gate. But I want to construct it using a minimum number of gates.
-2
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1answer
92 views
2
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1answer
69 views

In Qiskit, when creating multi-bit quantum and classical registers, what is the ordering of MSB to LSB?

When creating multi-bit quantum and classical registers, what is the ordering of MSB to LSB? For instance, I created a quantum register via ...
2
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0answers
50 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?
2
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0answers
51 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: <...
1
vote
1answer
79 views

Backend Warning: The skip Qobj validation does not work for IBMQ provider. Disable it

I am using QAOA to solve the max-cut problem. On my machine, 10 qubits already takes a minute or two to simulate. I'm hoping that the ibmq-qasm-simulator could simulate 32 qubits faster than my laptop ...
1
vote
1answer
42 views

Question on using the Collect2qBlocks() and ConsolidateBlocks() optimizations

I'd like to run the optimizations from Qiskit's level 3 transpiler pass on some example programs for benchmarking, but when I try to include the Collect2qBlocks() and ConsolidateBlocks() passes I get ...
3
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2answers
133 views

Big Endian vs. Little Endian in Qiskit

I've noticed that Q# favors Little Endian. Meaning that most operations are designed for this type of encoding. Is is it the same with Qiskit?