Questions tagged [fidelity]

In quantum information theory, fidelity is a measure of the "closeness" of two quantum states. It expresses the probability that one state will pass a test to identify as the other. The fidelity is not a metric on the space of density matrices, but it can be used to define the Bures metric on this space. (Wikipedia)

6 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
9
votes
0answers
95 views

Does higher channel fidelity imply higher entanglement fidelity?

Consider two noisy quantum channels (CPTP maps), $\Phi_1^A$ and $\Phi_2^A$, acting on a system $A$. Suppose that for any pure state $\left|\psi\right>\in \mathcal H_A$, $$ F\big(\psi, \Phi_1^A(\psi)...
7
votes
1answer
137 views

On the distribution of the fidelity of a random product state with an arbitrary many-qubit state

Consider an arbitrary $n$-qubit state $\lvert \psi \rangle$. How much do we understand about the probability distribution of the fidelity of $\lvert \psi \rangle$ with a tensor product $\lvert \alpha \...
5
votes
0answers
97 views

What are the “nice” properties of the diamond norm and why is it used?

I have heard about the diamond norm, and from what I understood it is a "nice" tool to quantify quality of quantum gates in the NISQ era. I would like to know a little more before going in detail in ...
3
votes
0answers
82 views

How to implement the mixed quantum state fidelity in a quantum circuit?

Suppose we use Uhlmann-Josza fidelity $F(\rho, \sigma):=(\mathrm{tr}\sqrt{\sqrt{\rho}\sigma\sqrt{\rho}})^2$, can we construct a quantum circuit that help us to calculate the fidelity of two mixed ...
0
votes
0answers
39 views

How can I find the fidelity of preparation?

I want to know the fidelity (or error rate) of the preparation ($|0\rangle$) How can I have it?
-1
votes
0answers
29 views

what is the accuracy real quantum circuit can achieve? what is the accuracy 𝜀 in real quantum circuit is reliable?

According to Solovay-Kitaev theorem, we know that set of universal quantum gates can approximately achieve any single qubit gate with a specific accuracy $\epsilon$. This is also a process of ...