Friday, October 07, 2022

Strawberry Fields Forever ...


Equipoise - 2019

Nothing is real until a "measurement" is taken yet everything's connected, sounds like Strawberry Fields  Forever does it not as Alice lives here without question thanks to quantum physics and the notion of entanglement and probabilities writ large.

One of the more unsettling discoveries in the past half century is that the universe is not locally real. “Real,” meaning that objects have definite properties independent of observation—an apple can be red even when no one is looking; “local” means objects can only be influenced by their surroundings, and that any influence cannot travel faster than light. Investigations at the frontiers of quantum physics have found that these things cannot both be true. Instead, the evidence shows objects are not influenced solely by their surroundings and they may also lack definite properties prior to measurement. As Albert Einstein famously bemoaned to a friend, “Do you really believe the moon is not there when you are not looking at it?”

This is, of course, deeply contrary to our everyday experiences. To paraphrase Douglas Adams, the demise of local realism has made a lot of people very angry and been widely regarded as a bad move.

But under quantum mechanics, particles are not like socks, and only when measured do they settle on a spin of up or down. This is EPR’s key conundrum: If Alice’s particles lack a spin until measurement, how then when they whiz past Neptune do they know what Bob’s particles will do as they fly out of the solar system in the other direction? Each time Alice measures, she effectively quizzes her particle on what Bob will get if he flips a coin: up, or down? The odds of correctly predicting this even 200 times in a row are 1 in 1060—a number greater than all the atoms in the solar system. Yet despite the billions of kilometers that separate the particle pairs, quantum mechanics says Alice’s particles can keep correctly predicting, as though they were telepathically connected to Bob’s particles.

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