Assuming protons don’t decay and that there’s no big rip, I feel like you can do obnoxiously large numbers. Build a clock out of superconductors that consumes 0 power until the top bit flips over (since incrementing a counter is reversible, this should be possible). Then, when your “alarm” goes off, wake up the sentient being and let it have its last thought. The limit is now on the number of bits B in your clock. Assume this is somewhere between 10**67 (number of atoms in the galaxy) and 10**80 (number of atoms in the visible universe). Your wake-up time is now 2**(10**B).
Ignoring proton decay, don’t you still need to deal with entropy and losing energy? Like, you have some energy store to run your final computations, and I’d expect the hard part to be preventing that energy store from leaking out.
Assuming protons don’t decay and that there’s no big rip, I feel like you can do obnoxiously large numbers. Build a clock out of superconductors that consumes 0 power until the top bit flips over (since incrementing a counter is reversible, this should be possible). Then, when your “alarm” goes off, wake up the sentient being and let it have its last thought. The limit is now on the number of bits B in your clock. Assume this is somewhere between 10**67 (number of atoms in the galaxy) and 10**80 (number of atoms in the visible universe). Your wake-up time is now 2**(10**B).
Ignoring proton decay, don’t you still need to deal with entropy and losing energy? Like, you have some energy store to run your final computations, and I’d expect the hard part to be preventing that energy store from leaking out.
Yep, I think this kills it. I have a sort of argument in my head that nothing can emit energy slower than a black hole due to hawking radiation.