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5 votes

Is there a no-go theorem for or an upper bound on code threshold?

For communication under depolarizing noise, the threshold is exactly $50\%$. We have constructions that achieve this, and we can prove you can't do better. The key idea is that any protocol where you ...
Craig Gidney's user avatar
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9 votes

Is there a no-go theorem for or an upper bound on code threshold?

TL;DR: The threshold is not just a property of a quantum error correcting code. The existence and value of the threshold depends on the noise model (and also on the chosen decoding procedure). To ...
Adam Zalcman's user avatar
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2 votes

Can Wiesner's quantum money be realized (with logical qubits) today?

Today's logical memories are not good enough yet to realize Wiesner's quantum money scheme. Take a look at the screenshot below, taken from a recording of Shraddha Singh's QIP 2023 talk on Real-time ...
Peter-Jan's user avatar
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2 votes
Accepted

Why is the first logical unitary gate in this example fault tolerant?

However, because the first gate is acting on disjoint pairs of physical qubits, can the 2 𝑋 errors ever propagate to more than 2 𝑋 errors? Yes, 2 $X$ errors can propagate to 4 $X$ errors via the ...
Peter-Jan's user avatar
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7 votes
Accepted

Recent hardware advances towards fault-tolerant quantum computing and quantum error correction

This kind of thing is why: (That's just the easiest image I could find with a google search. It's from https://twitter.com/jjgarciaripoll/status/1295752348124553217 . Don't know what paper, but ...
Craig Gidney's user avatar
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