An Upper Bound on the Threshold Quantum Decoherence Rate
| dc.creator | Razborov, Alexander A. | |
| dc.date | 2003-10-21 | |
| dc.date.accessioned | 2026-07-07T06:08:08Z | |
| dc.date.available | 2026-07-07T06:08:08Z | |
| dc.description | Let $η_0$ be the supremum of those $η$ for which every poly-size quantum circuit can be simulated by another poly-size quantum circuit with gates of fan-in $\leq 2$ that tolerates random noise independently occurring on all wires at the constant rate $η$. Recent fundamental results showing the principal fact $η_0>0$ give estimates like $η_0\geq 10^{-6}-10^{-4}$, whereas the only upper bound known before is $η_0\leq 0.74$. In this note we improve the latter bound to $η_0\leq 1/2$, under the assumption $QP\not\subseteq QNC^1$. More generally, we show that if the decoherence rate $η$ is greater than 1/2, then we can not even store a single qubit for more than logarithmic time. Our bound also generalizes to the simulating circuits allowing gates of any (constant) fan-in $k$, in which case we have $η_0\leq 1-1/k$. | |
| dc.description | 9 pages | |
| dc.identifier | https://arxiv.org/abs/quant-ph/0310136 | |
| dc.identifier | http://arxiv.org/abs/quant-ph/0310136 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/91528 | |
| dc.subject | Quantum Physics | |
| dc.title | An Upper Bound on the Threshold Quantum Decoherence Rate | |
| dc.type | text |