I figured the probability adjustments the pump was making were modifying Everett branch amplitude ratios. Not probabilities as in reasoning tools to deal with incomplete knowledge of the world and logical uncertainty that tiny human brains use to predict how this situation might go based on looking at past ‘base rates’. It’s unclear to me how you could make the latter concept of an outcome pump a coherent thing at all. The former, on the other hand, seems like the natural outcome of the time machine setup described. If you turn back time when the branch doesn’t have the outcome you like, only branches with the outcome you like will remain.
I can even make up a physically realisable model of an outcome pump that acts roughly like the one described in the story without using time travel at all. You just need a bunch of high quality sensors to take in data, an AI that judges from the observed data whether the condition set is satisfied, a tiny quantum random noise generator to respect the probability orderings desired, and a false vacuum bomb, which triggers immediately if the AI decides that the condition does not seem to be satisfied. The bomb works by causing a local decay of the metastable[1] electroweak vacuum. This is a highly energetic, self-sustaining process once it gets going, and spreads at the speed of light. Effectively destroying the entire future light-cone, probably not even leaving the possibility for atoms and molecules to ever form again in that volume of space.[2]
So when the AI triggers the bomb or turns back time, the amplitude of earth in that branch basically disappears. Leaving the users of the device to experience only the branches in which the improbable thing they want to have happen happens.
And causing a burning building with a gas supply in it to blow up strikes me as something you can maybe do with a lot less random quantum noise than making your mother phase through the building. Firefighter brains are maybe comparatively easy to steer with quantum noise as well, but that only works if there are any physically nearby enough to reach the building in time to save your mother at the moment the pump is activated.
This is also why the pump has a limit on how improbable an event it can make happen. If the event has an amplitude of roughly the same size as the amplitude for the pump’s sensors reporting bad data or otherwise causing the AI to make the wrong call, the pump will start being unreliable. If the event’s amplitude is much lower than the amplitude for the pump malfunctioning, it basically can’t do the job at all.
In real life, it was an open question whether our local electroweak vacuum is in a metastable state last I checked, with the latest experimental evidence I’m aware from a couple of years ago tentatively (ca. 3 sigma I think?) pointing to yes, though that calculation is probably assuming Standard model physics the applicability of which people can argue to hell and back. But it sure seems like a pretty self-consistent way for the world to be, so we can just declare that the fictional universe works like that. Substitute strangelets or any other conjectured instant-earth-annihilation-method of your choice if you like.
Because the mass terms for the elementary quantum fields would look all different now. Unclear to me that the bound structures of hadronic matter we are familiar with would still be a thing.
I figured the probability adjustments the pump was making were modifying Everett branch amplitude ratios. Not probabilities as in reasoning tools to deal with incomplete knowledge of the world and logical uncertainty that tiny human brains use to predict how this situation might go based on looking at past ‘base rates’. It’s unclear to me how you could make the latter concept of an outcome pump a coherent thing at all. The former, on the other hand, seems like the natural outcome of the time machine setup described. If you turn back time when the branch doesn’t have the outcome you like, only branches with the outcome you like will remain.
I can even make up a physically realisable model of an outcome pump that acts roughly like the one described in the story without using time travel at all. You just need a bunch of high quality sensors to take in data, an AI that judges from the observed data whether the condition set is satisfied, a tiny quantum random noise generator to respect the probability orderings desired, and a false vacuum bomb, which triggers immediately if the AI decides that the condition does not seem to be satisfied. The bomb works by causing a local decay of the metastable[1] electroweak vacuum. This is a highly energetic, self-sustaining process once it gets going, and spreads at the speed of light. Effectively destroying the entire future light-cone, probably not even leaving the possibility for atoms and molecules to ever form again in that volume of space.[2]
So when the AI triggers the bomb or turns back time, the amplitude of earth in that branch basically disappears. Leaving the users of the device to experience only the branches in which the improbable thing they want to have happen happens.
And causing a burning building with a gas supply in it to blow up strikes me as something you can maybe do with a lot less random quantum noise than making your mother phase through the building. Firefighter brains are maybe comparatively easy to steer with quantum noise as well, but that only works if there are any physically nearby enough to reach the building in time to save your mother at the moment the pump is activated.
This is also why the pump has a limit on how improbable an event it can make happen. If the event has an amplitude of roughly the same size as the amplitude for the pump’s sensors reporting bad data or otherwise causing the AI to make the wrong call, the pump will start being unreliable. If the event’s amplitude is much lower than the amplitude for the pump malfunctioning, it basically can’t do the job at all.
In real life, it was an open question whether our local electroweak vacuum is in a metastable state last I checked, with the latest experimental evidence I’m aware from a couple of years ago tentatively (ca. 3 sigma I think?) pointing to yes, though that calculation is probably assuming Standard model physics the applicability of which people can argue to hell and back. But it sure seems like a pretty self-consistent way for the world to be, so we can just declare that the fictional universe works like that. Substitute strangelets or any other conjectured instant-earth-annihilation-method of your choice if you like.
Because the mass terms for the elementary quantum fields would look all different now. Unclear to me that the bound structures of hadronic matter we are familiar with would still be a thing.