You already get arbitrarily high upper bounds with reversible computation, and waiting until the universe gets cooler can yield 10^30x additional computation, no need for weirder physics. Bostrom mentioned both above, he was pretty explicit about the 10^85 ops cosmic endowment being a conservative lower bound. Krauss & Starkman’s 1.35e120 ops bound derived from the observed acceleration of the universe is the non-weird physics upper bound AFAIK (h/t Wei Dai).
Except, any physical reversible computing device is surely going to have to mantain itself against random fluctuations, which may make there be mounds on how long actually achievable devices could compute for.
You already get arbitrarily high upper bounds with reversible computation, and waiting until the universe gets cooler can yield 10^30x additional computation, no need for weirder physics. Bostrom mentioned both above, he was pretty explicit about the 10^85 ops cosmic endowment being a conservative lower bound. Krauss & Starkman’s 1.35e120 ops bound derived from the observed acceleration of the universe is the non-weird physics upper bound AFAIK (h/t Wei Dai).
Except, any physical reversible computing device is surely going to have to mantain itself against random fluctuations, which may make there be mounds on how long actually achievable devices could compute for.