Questions tagged [quantum-gate]
For questions regarding usage, performance, implementation, application or theory related to quantum gates.
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What is the name for quantum gates that can be reversed?
Sorry if this question sounds too basic. But I can't find a word for those quantum gates than can be reversed (exchanging the target qubit with the control qubit) and still performs the same operation....
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Is it possible to use quantum state to store and read information without destorying it?
Like building a ROM device? Please consider the influence of the non-cloning theorem and better show some papers. Thanks!
PS: I heard that error-correction methods might help to achieve this goal. Is ...
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RZZ from CNOT and RZ
The following should represent an RZZ gate (source: https://pennylane.ai/qml/demos/tutorial_qaoa_maxcut.html)
How do the CNOT and an RZ compute mathematically to the RZZ?
$$ R_Z(\theta) = \begin{...
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Decompose 8x8 Unitary Matrix into tensor product of three phased gate
We try to decompose 8x8 unitary matrices
\begin{pmatrix}
e^{ia} & & & & & & \\
& e^{ib} & & & & & \\
& & e^{ic} & & ...
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Faithful description of a photonic setting with the circuit model
The above picture comes from this paper.
The circuit on the left and the one on the right are equivalent (up to the basis).
However, there is an important difference: the circuit makes the input -- i....
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Is it possible to get the "symbolic" matrix operator associated with a parameterized quantum circuit using Qiskit?
Qiskit provides the qiskit.quantum_info.Operator class to get the unitary matrix operator from the corresponding quantum circuit, as in the following example:
...
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How to decompose 8x8 Unitary Matrix into tensor product of three phased gate?
Our goal is decompose 8x8 unitary matrices $U_j$ to extend the Solving TSP with Quantum Phase estimation
$U_j = \begin{pmatrix}
e^{ia}& 0& 0& 0& 0& 0& 0&0 \\
0&...
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Is there any method to parse a qasm in qiskit
I'd want to parse the qasm file for analyze the quantum gate consisting its qasm file.
However, Qiskit provides the attribute of the quantum circuit, ...
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How does the stated Pauli decomposition for $\operatorname{CP\cdot A\cdot CP}$ arise?
I'm having a bit of trouble understand @DaftWullie's answer here.
I understood that the $4\times 4$ matrix $A$
$$ \frac{1}{4} \left[\begin{matrix}
15 & 9 & 5 & -3 \\
9 & 15 & 3 &...
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Solving a circuit implementing a two-level unitary operation
The circuit below implements the following two-level unitary transformation:
$\tilde{U}$ is a unitary matrix: $\tilde{U} = \left[\begin{matrix} a & c \\ b & d \end{matrix}\right]$
where $a, ...
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Is there a quantum gate that can do this?
Is there a quantum gate that can do the following?
Given a first set of N qbits, mutually entangled in such a way that each state in the superposition meets a given condition, generate a second set of ...
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How do I apply a Hadamard gate on a given qubit, in matrix formalism?
Hadamard gate matrix is:
$$\frac{1}{\sqrt2}\begin{bmatrix}1 & 1 \\ 1 & -1\end{bmatrix}$$
The matrix for $|0\rangle$ is:
$$\begin{bmatrix}1 \\ 0\end{bmatrix}$$
I am unable to understand, how ...
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How can the state $\lvert0\rangle+M^{-1/2}\sum_{j=1}^M\lvert j\rangle$ be generated?
I was wondering if anybody to help me to generate the following state.
It would be preferable if you use only Hadamard, CNOT and T-gates, on $\lceil\log_2(M+1)\rceil$ qubits:
$$|\psi\rangle = \frac{1}{...
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How to make Controlled-CRY Gates
I found that how to make CRY Gates.
But I don't know how to make Controlled-CRY Gates.
Please show me a figure.
Sorry for the poor English.
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Simplify the system to find the $\theta$, $\phi$ on bloch sphere [duplicate]
I have problem to simplify the quantum system states on bloch sphere to get $\theta$, $\phi$ values,
My question is not duplicated!
$$
\left| \varphi \right>=\frac{1+i}{\sqrt{3}} \left| 0 \right>...
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How does the graphical notation used to denote doubly-controlled gates work?
$\qquad$
$\qquad$
What is the difference between solid and hollow? How to express the corresponding matrix of these figures? In addition, if they are not adjacent, what should be done in the middle of ...
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How can you construct the different two-qubit Bell states?
How can you construct the different Bell states? For example $$\frac{|01⟩-|10⟩}{\sqrt{2}}$$
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What's the matrix representation of this 3-qubit CZ circuit?
How do I calculate the matrix representation of this part of a teleportation circuit? It must be a matrix of dimension 8.
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Why 2 $H$ gates in series create a probability of 100% for one value of the qubit and 0% of the second value of the qubit?
Why 2 $H$ gates in series create a probability of 100% for one value of the qubit and 0% of the second value of the qubit since an $H$ gate acts like a superposition generator?
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How is it possible to perform a c-not on 4 qubits using the same control qubits on IBM Q computers?
I was wondering after seeing ibmq_16_melbourne layout how it is possible to perform this circuit :
It seems when looking at ibm q computers that a qubits can at max target 3 qubits because the arrow ...
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Implement approximate $Ry(2\pi /3)$ with gate set {$Rx(\pi),Ry(\pi),Rz(\pi),Rx(\pm \pi/2),Ry(\pm \pi/2),Rz(\pm \pi/2),T,S,H,CZ$}
With gate sets {$Rx(\pi),Ry(\pi),Rz(\pi),Rx(\pm \pi/2),Ry(\pm \pi/2),Rz(\pm \pi/2),T,S,H,CZ$}, I want to implement an approximate $2\pi/3$ rotation around Y axis. An ancilla qubit can be used as well. ...
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Writing Toffoli Gate Matrix by one and two qubit gate matrices
I am trying to write Toffoli gate matrice by using one and two qubit gates matrices.
I follow this circuit
link for the circuit
I first started to write the matrices of one and two qubit gates:
...
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In quantum teleportation, Is it possible for bob to just see the state vector after receiving it from Alice without measuring it?
I was reading about quantum teleportation using Qiskit. Alice wants to teleport some quantum state to Bob. My question is Is it possible for bob just to see the state vector after receiving it from ...
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Is this interpretation of quantum circuits right?
Just need some clarification: Results derived as the output of "running" a "quantum circuit" constructed from "quantum gates" are distributed in a certain way, based on the design, and the multiple ...
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Represent qubit in a superposition [closed]
How do we represent a qubit $\vert 1 \rangle$ and put in a superposition (in dirac)?
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Swap test to calculate inner product with qiskit for multi-qubit states
Is it possible to perform a controlled swap test with multiple targets with qiskit? I have tried using cswap(ancilla[0],qb1,qb2), where qb1 is an n-qubit register and qb2 is as well
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import error :No module named 'qiskit_aqua'
I have an error when I use Quantum SVM kernel algorithm from Qiskit aqua.
This is my code section with imports:
...
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Prove that a C2(U) gate (for any single qubit unitary U) can be constructed using at most eight one-qubit gates, and six controlled- NOTs [duplicate]
Its a Problem from
Michael Nielsen quantum computation and quantum information
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Does a CNOT quantum gate violate no cloning theorem? [duplicate]
I am a curious quantum computing learner. :)
Once observe the CNOT gate:
as you can see there it converts a |+> to |-> in the top or to say in another way it clones the |->
state. So does ...
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How does one interpret intuitively the CNOT gate?
How does one interpret the CNOT gate? The CNOT gate takes a separable state and turns into an entangled state. The oracle in the Deutsch algorithm does the same thing. But how does one understand this ...
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How to decompose square root SWAP gate in Mathematica
The Quantum Mathematica add-on package is a very good tool to implement quantum gates. It contains gates as shown in this figure.
How to use these gates to decompose square root SWAP gate?
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Are quantum gates superoperators? How to write a quantum circuit as superoperator?
I have some questions related to superoperators:
What is the differences between quantum operators and superoperators? For instance quantum gates are also unitary operators but can we say quantum ...
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Cannot interpret transformations on the bloch sphere as matrix multiplications
I understand that X,Y and Z gates are rotations around the axes with the respective letters, but I cannot understand how can Y gate multiply the amplitude of 0 with unreal number and have it landing ...
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Generating a random 16-digits in a superposition state using Qiskit
Im trying to create a script using Qiskit for a days but somehow i couldn't seem to get it done!! Im new to QuantumComputing, so pardon me if i don't explain something properly. I need to create a ...
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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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