1
$\begingroup$

The engineered dissipation approach enables autonomous error correction, and Kerr-cat qubit supports bias-preserving gates which brings done the cost of fault-tolerant error correction by utilizing the noise structure. It seems bosonic qubits are really good in terms of error correction. I'm curious about what's the down-side of them? Are physical gate errors too high? Or is the coherence time too short? Or are they hard to manufacture?

$\endgroup$

2 Answers 2

2
$\begingroup$

It's true what you are saying. Sadly they have a problem called loss. In a larger circuit the loss will be significant and we will not get the estimated output. If you want to know more about this I recomend you the Xanadu Quantum Photonics web: https://strawberryfields.ai/photonics/concepts/index.html

$\endgroup$
0
1
$\begingroup$

I'm not an expert on this platform, but I believe one of the main problem with Kerr-cat qubits are practical problems from working with not perfectly coherent states. An ideal coherent state $$|\alpha\rangle = e^{-|\alpha|^2}\sum_{n=0}^{\infty} \frac{\alpha^n}{n!}|n\rangle$$ should be protected from annihilation losses. However, they also have an infinite number terms which include arbitrarily large $|n\rangle$. Even though such states have exponentially small coefficients, I believe the large (to infinite) energies associated with these higher terms causes such states to be incredibly difficult to generate and extremely lossy (with some kind of $n$-dependent loss process). For this reason, I think most demonstrations use a truncated Kerr-cat code which realizes many of the benefits, but only goes out to a fixed $n$ which means the qubit isn't fully protected from annihilation losses.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.