Time-reversal of an unknown quantum state

phys.org

23 points·samizdis··7 comments

T-symmetry https://en.wikipedia.org/wiki/T-symmetry > See also links to "reversible computing" but not the "time reversal" disambiguation page?

The "teeter-totter" thought experiment on that page is interesting to me in that it seems to illustrate how the future has more possibilities than the past. But it also occurs to me that the future possibilities are fractal with the past - ie. the toy could fall onto one of many other lower pedestals, teetering as it was before. In this way the "many arbitrary" possibilities could be perceived as anything but.

Could there be multiple "collapsed" paths which consistently converge at the current or future measured state?

http://blog.rongarret.info/2014/10/parallel-universes-and-ar...

> The punch line is this: the statement that we can't time-travel into the past is exactly the same as the statement that we can only remember the past.

Note that the author's definition of "time travel" is a very specific one which, e.g., has nothing to do with the way time travel is defined in General Relativity.

The last line: "This procedure is to be implemented on the emergent quantum computers with the on-demand thermalizable qubits."

As someone with more familiarity with quantum computer science than its implementation via "computers," I ask: is it feasible to instantaneously swap states as described on any near-term quantum computers? Of course, ignoring the issue of needing sufficiently many ancilla to render the reversal accurate.

It certainly appears to be a novel theoretical result, but I question its practicality. The title was kind of click-bait lol

Quantum debugger?

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