Pranav Gopal Week 15 - Quantum Amnesia

Brent Kavanaugh // Unsplash

A couple days ago I found an iceberg chart of some interesting theories and thought experiments, starting from some more popular concepts like Roko's Basilisk to what incited my blog post this week, quantum immortality. As most things with "quantum" proceeding it tend to be, I didn't really understand much of it, but I reread the Wikipedia page a couple times and understood I was way out of my depth, and that my lack of brain power outweighed my curiosity.

However, while looking into some related topics, I found my discussion point for this weeks post: Quantum Amnesia. Unlike quantum immortality, this idea seems to have stemmed from a singular study in 2008 by Lorenzo Maccone, and is a lot easier and simpler to follow. 

The basis of this topic is the concept of an "arrow of time," or the idea that time is asymmetrical and flows in a one way direction. The "issue" in this is that the laws of physics and thermodynamics are all symmetrical and can occur regardless of time going forwards or backwards. However, everyday occurrences don't typically occur both forwards and backwards. So for example, food warmed up in the microwave will cool down when placed outside, but nobody ever sees food on a plate suddenly heat up. These phenomena are backed up by the Second Law of Thermodynamics, which indicates that the entropy of a closed system never decreases. Thus, systems will gradually increase in entropy, as heat dissipates into the surroundings and other energy transfers and processes occur. These processes, theoretically, should be the same regardless of time proceeding forwards or back, so why exactly don't we see spontaneous reactions like a cold cup warming up? 

Maccone hypothesizes that these reactions occur forward and backwards regularly, providing a very unique reason as to why nobody seems to see these "backwards" reactions. Maccone, in his paper, asserts that people who witness these events have their memories erased out of necessity, since time flows only asymmetrically. He justifies this by indicating that when a system is observed, the observer and the system enter a the state of quantum entanglement, where both cannot be described without the inclusion of the other. As a result, the observer's memory of the events are erased, such that the two are no longer entangled. 

While this theory may provide a "solution" for the asymmetrical nature of the arrow of time, Maccone's theory cannot really be proved since he can't concretely indicate that entropy-decreasing phenomena actually occur. Considering the erasure of memories, Huw Price, another quantum physicist, argues that it isn't feasible for everyone to have the same orientation of time towards the future and past. As a result, nothing really is explained or solved by adopting this very improvable theory. 

This asymmetrical nature of the arrow of time still persists, despite this very unique approach to solving it. Personally, it just appears like the creation of a new mystery rather than a solution to the old. However, it would be interesting to consider that my memories are being erased on a regular basis, though it does raise quite a lot of questions.