Questions tagged [quantum-gate]
For questions regarding usage, performance, implementation, application or theory related to quantum gates.
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questions with no upvoted or accepted answers
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How does using a controlled rotation gate , with the slope of the linear function as a parameter, loads that function onto the amplitude?
I was going through the paper Quantum Risk Analysis in the section III they came up with a technique, in which they represented the analytical function into a polynomial and then used the slope of ...
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Derivation of complexity for data encoding schemes
Could anyone help to derive the space-time complexities of the following different data encoding schemes ?
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Understanding the meaning of [2, 2] for input_register and target_register in a custom Cirq gate
I'm learning a custom gate implementation from google Cirq official tutorial of shor algorithm(https://colab.research.google.com/github/quantumlib/Cirq/blob/master/docs/experiments/shor.ipynb#scrollTo=...
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SX operator and superposition
I am running some tests using the probabilities we get from statevector to assert values in qiskit. For instance, with two qubits and a hadamard gate on the first one we have:
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Conjugation of Unitary Matrices in Quantum Channel
A quantum channel is given in the form $U(\rho)=\sum_{j}p_jK_j\rho K_j^\dagger$. I have read in another thread that a quantum channel is the generalized version of a quantum gate (represented by a ...
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Can Someone Help Me Create a Custom Feature Map with the Latest Version of Qiskit?
I am trying to create a custom feature map that I can use as input to the VQC classifier for classification purposes. I attempted to follow a GitHub repository: https://github.com/qiskit-community/...
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Physical implementation of error detection scheme with an ancilla qubit
I have two data qubits coupled with an ancilla qubit. I need a Hamiltonian H such that:
If the ancilla qubit is in state $|0⟩$, do nothing on the 2 qubits.
If the ancilla qubit is in state $|1⟩$, ...
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Quantum image encryption using NEQR and QTRNG
I have represented a 2x2 grayscale image using NEQR and I generated a key image using QTRNG. After the xor operation between the original and key image, I only need the encrypted image value, to avoid ...
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defining a unitary isometry
I am defining the coefficient unitary in full details but stuck. I tried many ways so that the cross terms gets cancelled and the diagonal terms has one.
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Pauli decomposed Hamiltonian as Diagonal U gate
While trying to implement a quantum circuit, I had to apply Hadamard gates to all qubits to achieve equal superposition. Done.
The next operation is decomposing the Hamiltonian into a sum of tensor ...
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Do I need a lab in order to test new ideas in designing quantum circuits
I would like to know how to test new ideas certainly on a circuit level. Do I require a lab? if so where can I find one I live in Houston. Does nt quantum eliminate the necessity of a lab and can I ...
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how do i get the sequence of resulting data on the ibm quantum computers platform?
I have been working on the ibm quantum computer platform, but i have faced a problem with the output. My circuit contains Hadamard gates and entanglement gate between two qubits. I want to get the ...
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How to construct a high-dimensional Lagrange unitary operator in IBM Quantum Cloud Platform?
Introducing a new generalized unitary operator - Lagrange unitary operator, which is expressed as
$M(\theta ) = \sum\limits_{j,k = 0}^{d - 1} {\frac{{\prod\nolimits_{k \ne j} {({e^{i\theta }} - {\...
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how does one get native 2-body measurements?
How are Majorana-based architectures able to possess native 2-body measurement operations? Could anyone provide an appropriate reference explaining that?
Are those native measurement operations ...
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Conditions for Fault-tolerant QC to work better than not doing any EC (except the ideal decoder)
I've been exploring fault-tolerant QC with the simplest 7-qubit Steane code, yes I'm able to obtain all the predicted thresholds for various transversal gates and the EC gadgets. I then tried to ...
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How can i describe Custome Gate Sets in Cirq?
i try to create a Custome GateSet with the CompilationTargetGateset class but it does not work.
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Apply Hadamard on a qubit in a register
I want to implement a Hadamard gate on a single qubit in a register.
Given two qubits
q0 := $|0\rangle$ and
q1 := $|+\rangle$
I would like to use a Hadamard gate on the first qubit (q0).
My intuition ...
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How to calculate weight matrix of Hamiltonian for logic gate?
How can we find the $J$ matrix representing a logic gate truth table?
$$H=-\sum_i h_im_i-\sum_{i\lt j}J_{ij}m_im_j,$$
with
$$J=\begin{bmatrix}0 & -1 & +2 \\-1 & 0 & +2\\+2 & +2 &...
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Represent bit flip gate in mathematical formula to move phase in Controlled-Controlled-Phased Gate
I desire to decompose Unitary Matrix $U_j(a,b,c,d,e,f,g,h)$ into tensor product of three phased gate to implement Quantum Phase Estimation.
We have 3 phased-gate
$P_1 = \begin{pmatrix}
1 & 0 \\
0 &...
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How to use more than 3 classical registers in a single quantum circuit in Qiskit without getting error: not enough memory slots?
I'm trying to run a quantum circuit on qasm simulator which has more than 3 classical registers. It gives error when I try to execute it. The circuit looks ...
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How to represent the following regular quantum circuits with tensor and concatenation symbols?
I am fascinated by such a quantum structure as above, how should the regular distribution for Toffoli and SWAP gates be described by the formula? Is the following correct?
$\prod\limits_{n}{{{I}_{{{2}^...
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How can the result of 1 million transformations on a qubit be verified to be correct?
I tried to do almost a million transformations on a qubit.
I made a three qubit circuit with equal superposition of |0> and |1> (using Hadamard gate) and on the first qubit (qubit 0), added one ...
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Building Unitaries in TSP Quantum Phase Estimation Qiskit?
In the paper [https://arxiv.org/pdf/1805.10928.pdf] 2 published by IBM, they use Quantum Phase Estimation to solve the TSP problem. I don't understand the reason why they can decompose the diagonal ...
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Sample random unitary at a given distance from a given unitary
Is it possible?
I.e., what is the most natural procedure of such sampling? The sampling has to be 'uniform' in a vicinity (of radius $\epsilon$) of given $U$ (can I say "according to Haar measure ...
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Mapping a classical cipher into quantum implementation of Grover Oracle
I am translating simple ciphers into quantum implementation in order to create oracle for Grover algorithm. I have started the task with a light weight SPECK cipher (got both classical and quantum ...
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How we can switch the digital multi-qubit gates to analog multi-qubit blocks?
What is the difference between the digital and Analog Quantum gate? and the multi-qubit gates involved in a VQE ansatz can be switched to analog multi-qubit blocks. so How we can switch the digital ...
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I have two quastion about n-MCT gate decomose into Clifford+Zn
this figure from paper ：New techniques for fault-tolerant decomposition of Multi-Controlled Toffoli gate
can someone tell me why cir1 is different from cir 2 , can they all represent Toffoli?
the ...
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General Shape of the Hamiltonian for a Desired Unitary
Suppose that, the unitary(the gate) that we want to have is 8*8 matrix. Now I want to write the most general shape of the Hamiltonian for my unitary and I want to prove that the unitary can be ...
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Minimal decomposition for a 4 qubit QFT in a Superconducting architecture
i'm looking for a minimal decomposition in terms of Cnot for the 4 qubit QFT circuit in the 7 qubit architecture reported in figure. I'm using qubits 0,2,4,6 as ancillas for my QPE algorithm.
The ...
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Which book(s) us(es) the CNOT representation $e^{i\frac{\pi}{4}\left(I-Z\right)\otimes\left(I-X\right)}$?
I am looking for a book that uses the following representation of a CNOT , that so far I have only seen on Wikipedia. Because I'd like to properly cite the source, I am looking for a book that uses it:...
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Find unitary $U$ that transforms state $|\phi \rangle$ to state $|\phi' \rangle$ knowing those states differ only by relative phase
Given:
$|\phi \rangle = \sum_n c_n |a_n \rangle $
$|\phi' \rangle = \sum_n c'_n |a_n \rangle $
such that $\forall n: c_n = c'_n \lor c_n = -c'_n $, where $|a_n \rangle $ is a canonical basis,
and ...
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Quantum Haar Wavelet Transform
I am working on understanding the quantum haar wavelet transform and trying to understand how it actually do the dimension reduction mathematically. A lot of people suggested me to read this paper : ...
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Why are the angle coding of the samples cascaded and only use so few qubits
I want to ask about the angle coding. Is the angle coding that Abbas said really like this? There are two samples and four features. Why does she only use two qubits? Instead of four. And the sample ...
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How do you build the modified Toffoli gate using only local unitary and CNOT operations?
How do you build a circuit for a modified Toffoli gate using only local unitary operations and CNOT operations? The two-qubit unitary operation is given by: $\text{diag}\{1, 1, 1, e^{i\phi}\}$.
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Is there a simple quantum gate that shows off the power of Quantum interference?
I'm trying to build a deep understanding of where the power of quantum computing comes from when compared to probabilistic computing. A naive observation might be that probabilistic computing would be ...
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After a photon passes through the phase shifter, does it gain the geometric phase or dynamical phase?
In Quantum Mechanics, the phase can be divided into geometric phase and dynamical phase. In mach-zehnder interferometer, after the photon passes through the phase shifter, what kind of phase does it ...
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Folded MPS state with Mid-circuit measurement
Among some documents I found to make a MPS state on quantum circuit, I can make it with stepped arrangement of unitary operators.
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How to use the csv dataset file imported as a dataframe in QSVM Qiskit code
I am trying to run QSVM qiskit code with my custom dataset which I am loading as a pandas dataframe. When I execute the part below with my own dataset in the place of breast_cancer, it gives error &...
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Implementing Cirq Coding Gates
Can someone please help me making these gates on CIRQ programming:
Decrement Gate (-1)
Splitter Gate (If possible)
I was having trouble implementing these and was not sure if it's possible either.
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Silicon and Germanium semiconductors mixture in quantum computing
Can Silicon and Germanium semiconductors mixture (chemical reaction) with some other chemical elements (if required) assist in creating new and existing robust electronic components?
Si + Ge + ? + ? =
...
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