I’m pretty sure I don’t… Wikipedia: “Viewed in isolation, the system’s dynamics are non-unitary (although the combined system plus environment evolves in a unitary fashion). Thus the dynamics of the system alone, treated in isolation from the environment, are irreversible. As with any coupling, entanglements are generated between the system and environment, which have the effect of sharing quantum information with—or transferring it to—the surroundings.”
If you draw a notional, boundary around a system that is embedded in an environment and consider it in isolation, then you introduce an asymmetry due to the information lost crossing the boundary.
The system+environment evolves in a unitary fashion, but you can’t do anything to reverse the universe.
The only hope of reversing is a system is if it actually is isolated...inot interacting with with an environment.
The environment can be larger than whatever system you drew a notional boundary around and still smaller than the universe, so not being able to reverse the universe isn’t a problem. Here, I’ll make it explicit: imagine it turns out that your “environment” is actually a Laplacian monstrosity! You’re just a subsystem. All concerns about irreversibility are thenceforth questionable.
I’m pretty sure I don’t… Wikipedia: “Viewed in isolation, the system’s dynamics are non-unitary (although the combined system plus environment evolves in a unitary fashion). Thus the dynamics of the system alone, treated in isolation from the environment, are irreversible. As with any coupling, entanglements are generated between the system and environment, which have the effect of sharing quantum information with—or transferring it to—the surroundings.”
If you draw a notional, boundary around a system that is embedded in an environment and consider it in isolation, then you introduce an asymmetry due to the information lost crossing the boundary.
The system+environment evolves in a unitary fashion, but you can’t do anything to reverse the universe.
The only hope of reversing is a system is if it actually is isolated...inot interacting with with an environment.
(relevance to quantum computing)
The environment can be larger than whatever system you drew a notional boundary around and still smaller than the universe, so not being able to reverse the universe isn’t a problem. Here, I’ll make it explicit: imagine it turns out that your “environment” is actually a Laplacian monstrosity! You’re just a subsystem. All concerns about irreversibility are thenceforth questionable.