Questions tagged [simulation]
For questions about simulating either quantum computers or simulating things on quantum computers.
304
questions
0
votes
0
answers
9
views
How does uncomputation vs a reset effect the measurement
I am new to quantum computing, and am trying to understand how uncomputing a qubit differs from a reset. In the first pictured circuit I am performing a reset on the second qubit. A measurement on the ...
1
vote
1
answer
24
views
What is the most efficient way to run several simulations of parameterized quantum circuits in Qiskit?
Suppose I am given a parameterized quantum circuit in Qiskit: as an example, here I consider a ZZFeatureMap ansatz, commonly used for data embedding in quantum ...
- 1,193
1
vote
1
answer
40
views
Qiskit: How much exact number of qbits simulator is capable of working with
My circuit is adding two 128 bits number and each input has been stored in 128 length quantum register (total 128*3 + carry in and out, 386). For calculation purpose I am using AER's different ...
- 201
0
votes
0
answers
17
views
Failed to load model class 'CircuitComposerModel' from module '@quantum/ibm-q-lab-widgets' on Jupyter Lab [closed]
The same question is also here, but no comments, nor any answer for this.
I am looking for composing the quantum circuit on Jupyter Lab, using Qiskit. However, the module gets into an error.
...
3
votes
0
answers
71
views
Understanding the Gottesman-Knill Theorem
I come from a theoretical CS background, and I am trying to gain a better appreciation of the exact formal statement of the Gottesman-Knill theorem in terms that I am more familiar with. My question ...
- 179
4
votes
1
answer
171
views
Does Gottesman-Knill theorem apply with any computational basis input?
On Wikipedia, the Gottesman-Knill theorem is said to state the following:
A quantum circuit using only the following elements can be simulated efficiently on a classical computer.
Preparation of ...
- 179
2
votes
2
answers
77
views
If sampling the output of $U_1U_2$ is easy, is sampling the output of $(U_1U_2)^\dagger$ also easy?
Let $U_1$ and $U_2$ be $n$-qubit unitaries, and denote by $P_{U_1U_2}(y \mid x) = |\langle y | U_1U_2 | x \rangle|^2$ the probability of measuring $y \in \{0,1\}^n$ on input $x \in \{0,1\}^n$. Suppose ...
- 179
1
vote
1
answer
68
views
How to convert a quantum circuit into a tensor network?
I need to perform tensor network contraction on a maxcut circuit, are there any resources or code available which converts maxcut circuit into a tensor network (preferably the adjacency list or any ...
0
votes
1
answer
45
views
Exact expectation value of a quantum circuit simulated with the matrix product state method in qiskit
If I use the matrix product state method in Qiskit to simulate quantum circuits, I can obtain the exepctation value of an observable by using a finite amount of shots. Is there a way to obtain the ...
- 385
1
vote
0
answers
12
views
How do I change the x and y axis on the results histogram for a ibmq_qasm.simulation resulting histogram?
Im following a textbook and when they ran the same circuit with the ibmq_qasm_simulator, their results histogram had computational basis state on the x axis and probability on the y axis, however my ...
- 11
0
votes
1
answer
73
views
Tensor network simulation of quantum circuits with Python
What are the best tensor network-based simulators libraries in Python?
In particular, I'm interested in calculating the expectation value of an observable measured at the end of a quantum circuit.
...
- 385
3
votes
2
answers
240
views
Is there any quantum annealer simulator offered by DWave?
I am searching for quantum annealer simulator offered by DWave. I found classical solvers in dimod packages that implement simulated annealing, but I couldn’t find solver that simulates the real ...
- 31
2
votes
1
answer
57
views
How to get a noisy density matrix after partial measurements in Qiskit
I'm trying to study the effect of noise on a quantum system with partial measurements using Qiskit. Suppose I have $N + M$ qubits and I run a quantum circuit and measure $M$ of them. I want to know ...
- 195
3
votes
2
answers
118
views
What is the mathematical essence of Qiskit simulators?
As a newcomer to quantum computing, I have a question about the simulation of a quantum computer using Qiskit on a classical computer. Does Qiskit actually perform matrix manipulations in its ...
- 79
0
votes
0
answers
15
views
Is it possible to run pulse callibrated gates on a simulated ibm backend
Currently I am trying to test a quantum algorithm that consists of calibrated quantum gates on a circuit. It needs to stay this way because I would like to run the algorithm on a real backend in the ...
3
votes
1
answer
71
views
What is the computational cost of simulating a quantum circuit with matrix product states?
If we simulate Quantum circuits with the Matrix Product State (MPS) technique, the computational cost of the simulation depends on the entanglement in the circuit. How can I calculate this quantity ...
- 385
1
vote
0
answers
24
views
How to calculate the Pauli Noise model of a physical gate operation?
I've seen literature and QuTip implementation of calculating a gate fidelity given the transformed density matrix, and in that case it uses a number of different initial states. My question however, ...
- 97
0
votes
1
answer
53
views
How to extract resulting qubit states from a circuit after one round of computation?
I'm running the simulation of some circuit on the Qiskit qasm_simulator backend. My end goal is running this simulation several times and finally extract for each iteration the final qubit state and ...
0
votes
1
answer
36
views
Is there a state vector simulator written in pure python?
For educational purposes, I am looking for a simulator written in pure python.
It may use scientific-python libraries such as numpy to exploit the data structures they provide, but the core algorithms ...
- 733
1
vote
1
answer
283
views
Is it possible to use fake backends to run Qiskit Runtime primitives?
I have the following code to run an Estimator primitive by using Qiskit Runtime. It computes the expectation value $\langle O \rangle = \langle \psi | O | \psi \...
- 1,193
0
votes
0
answers
72
views
Qiskit, possible to manipulate mid-circuit measurement outcomes?
I'm currently coding up an error correction gadget using qiskit.
The one I'm doing now is 7-qubit Steane code with Steane's error correction gadget, in which the ancilla qubits are measured and then ...
- 53
1
vote
0
answers
29
views
Non-local $CNOT$ By means of Ising gates
Consider the circuit below.
This is almost the same as the standard protocol to perform a non-local $CNOT_{0,3}$. The only difference is that I decomposed the upper local $CNOT_{0,1}$ into one Ising ...
- 1,166
2
votes
4
answers
291
views
Why do quantum computing simulators have the measurement function?
Quantum computing simulators like qasm_simulator in Qiskit Aer have a function to simulate quantum measurements (for example, the command of ...
- 23
4
votes
0
answers
74
views
Difference between IBM simulator backends
I'm an Msc student working on a quantum information project (VQEs on 4 qubits).
Our group is looking at different IBM simulators on the IBM platform, and have noticed that performance is different for ...
- 41
3
votes
1
answer
95
views
Simulation files for noisy quantum circuits
For our study with Yosi Rinott and Tomer Shoham we need the following simple data:
Starting with a quantum circuit $C$ on $n$ qubits we need two files:
a) A file of probabilities (or amplitudes) for ...
- 201
0
votes
0
answers
19
views
Why does SQcircuits give 0 as the quasiparticle decoherence rates for a transmon qubit?
I am a high schooler new to quantum computing and for my project I use SQcircuits to simulate the T1 of a transmon. However, looking through some literature, it seems that quasiparticle noise is ...
0
votes
0
answers
88
views
getting error while simulating LiH using VQE
I wrote code again using updated qiskit nature libraries but I am facing error , I need help to finding solution so that we can run this code on latest version of qiskit.
I am attaching code below........
0
votes
3
answers
149
views
Is it possible to get the "symbolic" matrix operator associated with a parameterized quantum circuit using Qiskit?
Qiskit provides the qiskit.quantum_info.Operator class to get the unitary matrix operator from the corresponding quantum circuit, as in the following example:
...
- 1,193
1
vote
0
answers
48
views
Is there a way the receive the value of a specific classical register after simulation?
I have several classical registers in my circuit that I'm simulating using qiskit, and I'm looking for a way to access the simulation results of a subset of them, desirably according to their name.
...
1
vote
0
answers
22
views
noise and classical bits (measurements ) in qiskit
I am using qiskit and LocalNoisePass to add custom noise to the gates. But there is a problem when there are classical bits in the circuits. The localNoisePass give this error
...
- 111
0
votes
1
answer
34
views
Simulation of large quantum circuits or available dataset
I need to obtain the expectation value of an observable (I do not care which one) of simulated large quantum circuits, like 30 or more qubits. The quantum circuit can be of any type, but it is ...
- 385
4
votes
1
answer
89
views
How to import noise model from IBM qiskit real device?
I am trying to import the noise model of an IBM 'large' device. I don't have access to the devices with more than 7 qubits so it doesn't allow me to import the backend and then do
...
- 55
3
votes
0
answers
90
views
Apply a single-qubit channel between in between two circuits in Qiskit
Suppose, you have two parts of a circuit in Qiskit, qc1 and qc2 on any number of qubits such that the entire circuit is given by
...
- 839
3
votes
0
answers
38
views
Expectation value of a time evolved circuit in the non-Z basis
I am new to qiskit and have hit a roadblock in my calculation. Given the following circuit:
...
- 31
2
votes
1
answer
81
views
How does Quantum Simulation actually solve the problem it poses?
The problem of quantum simulation is below:
Given a Hermitian matrix, $H$, compute the unitary $e^{-iHt}$ for any $t > 0$. Using this computed unitary, calculate $e^{-iHt}\psi$ for any given $\psi$
...
- 315
1
vote
1
answer
40
views
Use state vector simulator with TensorCircuit
Is there a option to use instead of tensor network contraction state vector simulator for quantum circuits? This might be useful for small sized circuits, but I would still like to use TensorCircuit s....
- 63
2
votes
0
answers
27
views
Simulation of algorithms with QFT on a classical computer
In paper The Quantum Fourier Transform Has Small Entanglement the authors showed that strong entanglement of qubits caused by QFT comes mainly from ordering the qubits. QFT itself prepares only weak ...
- 12.9k
1
vote
0
answers
39
views
Proof of $cos(Ht) = \sum_\sigma cos(\sigma) \left | w_\sigma \right > \left < v_\sigma \right |$ in Quantum Singular Value Transform
I am reading the grand unification of quantum algorithms, and read over the hamiltonian simulation technique.
However, I am a bit confused. They pose that
$
e^{-iHt} = cos(Ht) - isin(Ht)
$
for all ...
- 167
1
vote
1
answer
78
views
How to interface stim to a generic qiskit decoder?
I can generate encoder/decoder circuits for arbitrary QECC in qiskit. I tested a number of codes : $[[5,1,3]], [[7,1,3]],[[8,3,3]],\cdots$ and everything seems to work fine. The problem is that the ...
- 1,485
0
votes
1
answer
46
views
How to use MPP to measure the logical Z in stim
I'm trying to simulate 3 qubit (distance 3) bit-flip code in stim.
I wrote code similar to How to import a generic stabilizer code in stim using MPP operation. I found the following way yields logical ...
- 97
1
vote
1
answer
208
views
How do I apply depolarization error on 2 qubits using Qiskit?
I'm trying to apply depolarization error on a 2-qubit circuit using the Qiskit Aer noise module. My question is how can I apply the depolarization error to each of the qubits in my circuit? Does the ...
- 379
0
votes
0
answers
54
views
How to simulate pseudothreshold of surface code?
I would like to simulate the pseudothreshold of a surface code. I want to write code which is as low in abstraction as possible, to learn better. So, as a first attempt, I would like to avoid using ...
- 228
3
votes
0
answers
22
views
Qiskit: efficient way to create bound circuits?
I am running an optimization problem whose objective function $F(a)$ requires measuring N variational circuits $V_i(a)$ at each evaluation.
So, roughly, I have created N parametric circuits and I do:
<...
- 331
2
votes
1
answer
95
views
Computing gradients in parallel with cost from probs (Pennylane-Braket)
Do circuits that measure probabilities instead of expectation values benefit from parallel execution?
The Computing gradients in parallel with Amazon Braket tutorial shows how the multiple device ...
- 2,203
2
votes
0
answers
74
views
Parallel run of qiskit circuits
I am trying to run simulation instances of a parametrized circuit in parallel but my algorithm is extremely slow. Excuse my ignorance, but I just want to be sure that the circuits are indeed running ...
- 331
1
vote
0
answers
54
views
Are there non-stabilizer multi-qubit states that are easy to simulate?
The Gottesman-Knill theorem states that the following process is efficiently simulatable on a classical computer:
start of with a set of qubits in a computational basis
apply any amount of $H, S$ and ...
- 1,292
0
votes
0
answers
39
views
How can I graph the time evolution of an initial state under a given hamiltonian in Qiskit?
I'm trying to compare the graphs of the time evolution of a state under the action of a given hamiltonian (Heisenberg, Ising). I have the graphs of the classical simulation using the ~ and @ ...
0
votes
1
answer
58
views
How simulation of noisy quantum circuits is done in Qiskit using the statevector method
While performing VQE calculations of medium-sized molecules like H2O, using Qiskit AerSimulator with noise, I noticed that even for a large number of shots, the speed of simulation using statevector ...
- 214
1
vote
0
answers
13
views
projectq code hangs with only 8 qibts
I have written a simple projectq code with 8qbits in order to perform full addition but it gets stuck somewhere between without generating any error message. It worked fine for 4 qbits.
...
- 201
1
vote
1
answer
107
views
Insufficient memory to run circuit using the statevector simulator
I am a newbie to quantum and have been trying qiskit library for learning quantum computing (in order to explore quantum effects on cryptography). I am basically ...
- 201