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Re:Are “reversible” computers more energy efficient, faster?... by corysama on Saturday July 25, 2020 @07:55PM (#23953284)
Interestingly, programs for quantum computers must be reversible.

https://physics.stackexchange.com/questions/392414/again-why...

Re:Are “reversible” computers more energy efficient, faster?... by Strilanc on Sunday July 26, 2020 @09:30PM (#23961537)
Sort of. Measurement is not reversible, and often the most efficient method for uncomputing an intermediate value in a quantum computation is to measure it in the frequency domain and then perform a cheap fixup depending on what you measured [1]:

> Measurement based uncomputation intrinsically generates entropy (due to the X basis measurements), but it uses significantly fewer operations. So, ironically, we will optimize the energy usage of quantum computations not by staying pure to our reversible Landauer-less roots but instead by using an irreversible form of uncomputation that generates entropy.

1: https://algassert.com/post/1905