Questions tagged [quantum-process-tomography]

For all questions regarding quantum process tomography or derivatives thereof (like gate-set tomography). In quantum process tomography, processes that are performed on qubits are characterized rather than the state of the qubits themselves; see quantum state tomography for this.

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Quantum process tomography, non-trace preserving

Consider an unknown quantum process, i.e., a black box, acting on a physical quantum system described by a density matrix $\rho$ associated with a d-dimensional Hilbert space $\mathcal{H}$. A complete ...
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How to merge logical computation with encoding-decoding schemes

Usually QEC is treated in two different ways. Definition of a logical computation with a non-destructive QEC scheme Definition of a encoding-decoding scheme with destructive measurement after ...
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Optimising Tomography on logical computation

I already got part of the answer in thread. Which says that if I want to perform a state tomography on a known state, the estimation can be simplified. In the case of "GHZ-class", citing ...
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How to find the Kraus operators from the process matrix?

I am trying to find the Kraus operator from process matrix. For instance, suppose that for single qubit identity gate, I have the following process matrix: ...
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How to compute the unitary from the $\chi$ matrix obtained from QPT

I am trying to do quantum process tomography for one qubit and obtain the unitary for the gates that are applied on the qubit. I have studied the theory on process tomography from mike and ike and the ...
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How to describe the evolution of a density matrix using the Choi matrix?

How do I apply the Choi matrix on a Density matrix. Say my process is a Hadamard gate, and my input state is the ground state on 1 qubit (qubit id 0). $U = H = \dfrac{1}{\sqrt{2}} \begin{bmatrix}1&...
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Quantum State Tomography from IQ plane data

Background: I am given to understand that the steps of Quantum State Tomography (QST) are as follows for a single qubit: The qubit is in the state $\psi=a_0|0\rangle+a_1|1\rangle$ with density matrix ...
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Process Tomography for Blind Quantum Computation

Process Tomography can identify the quantum channel, while Blind Quantum Computation strives to hide the inputs using quantum gates. Given the user executes the same blind circuit multiple times (of ...
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In quantum process tomography, how does $\chi$ characterize a quantum process?

I'm working through Nielsen and Chuang and I'm pretty confused by the discussion of quantum process tomography. I'm trying to work through an example of 1-qubit state tomography given by N&C (box ...
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What is the best quantum process tomography method?

This question is somewhat related to this question. What is currently the best method for quantum process tomography? By best I mean, the one that can achieve the best accuracy of estimation per qubit ...
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What is the best method for estimating average channel fidelity?

This thesis shows an efficient way to estimate average channel fidelity (in chapter 4). However, it is somewhat old (from 2005). Are there any better methods out there? By better I mean: are there ...
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Can Gate Set Tomography work on Quantum Channels?

I stumbled across a new paper on gate set tomography. Can gate set tomography be applied to a quantum channel or multiple quantum channels? Will the same advantages still apply of not having to 'rely ...
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Can you perform quantum process tomography using an orthonormal basis the contains non Hermitian matrices?

In the thesis "Efficient Simulation of Random Quantum States and Operators" on page 25 there is a portion of text explaining a method for quantum process tomography. It claims that states ...
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What is quantum tomography useful for?

First time poster and just started with quantum computing for my master thesis, so I'm sorry if the question seems obvious. I understand that the tomography is used to reconstruct the state and/or ...
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How can I fit an unknown quantum channel?

Suppose that I have one noisy channel $\mathcal{E}$ and I want to fit it with another one $\mathcal{E}_0(p)$ that depends on some fitting parameter $p$. As both of this processes for me are ...
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How to measure a general two-qubits gate? Does it help to Bob and Alice?

Excuse me if this question is absurd. I discovered logic gates a few weeks ago. two-qubis Logic gates are represented by 4x4 matrices. Can they mimic a general density matrix of pairs of spin 1/2 ...
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Why the chi-matrix fidelity of the process is the fidelity of the chi-matrix noise map

I am following this paper, and I am stuggling with a derivation. Basically, I consider an orthonormal basis $\{B_i \}$ with respect to Hilbert-Schmidt scalar product, on the density matrix space $\...
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Is it possible to partial trace the $\chi$-matrix of $4$ qubits $q_0,q_1,q_2,q_3$ to obtain a description of what happens to $q_1$?

Considering a $\chi$-matrix of a circuit with, say, 4 qubits, is it possible to trace out 3 of them from $\chi$ - for example qubits $q_0$, $q_2$ and $q_3$ - thus gaining the process matrix describing ...
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What is the relationship between Choi and Chi matrix in Qiskit?

I'm struggling with the framework for quantum process tomography on Qiskit. The final step of such a framework is running fit method of ...
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How to perform Quantum Process Tomography for three qubit gates?

I am trying to perform Quantum process tomography (QPT) on three qubit quantum gate. But I cannot find any relevant resource to follow and peform the experiment. I have checked Nielsen and Chuang's ...
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