Arrow of Time and its Reversal on IBM Quantum Computer

March 13, 2019 9:31 AM

Arrow of Time and its Reversal on IBM Quantum Computer "Uncovering the origin of the arrow of time remains a fundamental scientific challenge. Within the framework of statistical physics, this problem was inextricably associated with the Second Law of Thermodynamics, which declares that entropy growth proceeds from the system’s entanglement with the environment ... Our findings break ground for investigations of the time reversal and the backward time flow in real quantum systems"
posted by Pericles (13 comments total)

Energy was input into the system to revert it to an earlier state. This is like putting an apple that has fallen off the counter back onto the counter. It's a cool trick, but 'reversing the arrow of time' is a massive overstatement.
posted by cirgue at 9:39 AM on March 13, 2019 [13 favorites]

Just you wait until a rogue IBM tech sends us all back to the autumn of '95, when anything seemed possible but everything went so wrong.
posted by Iridic at 9:53 AM on March 13, 2019 [20 favorites]

First post!
posted by grumpybear69 at 9:58 AM on March 13, 2019 [51 favorites]

Here is the coverage in phys.org. They make this analogy by way of explanation:

Most laws of physics make no distinction between the future and the past. For example, let an equation describe the collision and rebound of two identical billiard balls. If a close-up of that event is recorded with a camera and played in reverse, it can still be represented by the same equation. Moreover, it is not possible to distinguish from the recording if it has been doctored. Both versions look plausible. It would appear that the billiard balls defy the intuitive sense of time.

However, imagine recording a cue ball breaking the pyramid, the billiard balls scattering in all directions. In that case, it is easy to distinguish the real-life scenario from reverse playback. What makes the latter look so absurd is our intuitive understanding of the second law of thermodynamics—an isolated system either remains static or evolves toward a state of chaos rather than order.
...
The researchers then attempted to reverse time in a four-stage experiment.
....
Stage 3: Time reversal. [I omit the description] ... An obviously far-fetched analogy for the billiards example would be someone giving the table a perfectly calculated kick

This article has more details if anyone is curious to learn more, but like me, reluctant to try to digest the primary source.
posted by exogenous at 10:16 AM on March 13, 2019 [6 favorites]

One wag on Twitter: "Amazed that no-one's asked for Cher's comment on this"
posted by exogenous at 10:24 AM on March 13, 2019 [16 favorites]

Great Scott!
posted by Foosnark at 10:45 AM on March 13, 2019 [2 favorites]

First post!

I favorited your comment before you posted it, so it may would have had not willn’t beshowen up for you quite yet.
posted by Celsius1414 at 11:42 AM on March 13, 2019 [3 favorites]

That's the power of love!
posted by Quindar Beep at 11:59 AM on March 13, 2019

I will become a time traveller like you, until I took an arrow in the...
posted by I-Write-Essays at 12:19 PM on March 13, 2019 [5 favorites]

No word, I suppose, on the fruit flies and the banana.
posted by briank at 12:25 PM on March 13, 2019 [1 favorite]

I'm gonna go ask Mark Twain's opinion.
posted by hanov3r at 12:48 PM on March 13, 2019 [1 favorite]

> I'm gonna go ask Mark Twain's opinion.

They literally split Time's Arrow in twain!
posted by Arson Lupine at 2:28 PM on March 13, 2019 [3 favorites]

Not so fast.
posted by CheeseDigestsAll at 8:46 AM on March 15, 2019