This Twist on Schrödinger’s Cat Paradox Has Major Implications for Quantum Theory

Scientific American ^ | August 17, 2020 | Zeeya Merali on

[BenLurkin]

Wigner sharpened the paradox by imagining a (human) friend of his shut in a lab, measuring a quantum system. He argued it was absurd to say his friend exists in a superposition of having seen and not seen a decay unless and until Wigner opens the lab door.

[Nora] Tischler and her colleagues have carried out a version of the Wigner’s friend test. By combining the classic thought experiment with another quantum head-scratcher called entanglement—a phenomenon that links particles across vast distances—they have also derived a new theorem, which they claim puts the strongest constraints yet on the fundamental nature of reality.

Until quantum physics came along in the 1920s, physicists expected their theories to be deterministic, generating predictions for the outcome of experiments with certainty. But quantum theory appears to be inherently probabilistic. The textbook version...says that until a system’s properties are measured, they can encompass myriad values. This superposition only collapses into a single state when the system is observed...

Today most physicists concur that inanimate objects can knock quantum systems out of superposition through a process known as decoherence. Certainly, researchers attempting to manipulate complex quantum superpositions in the lab can find their hard work destroyed by speedy air particles colliding with their systems. So they carry out their tests at ultracold temperatures and try to isolate their apparatuses from vibrations.

Several competing quantum interpretations have sprung up over the decades that employ less mystical mechanisms...to explain how superpositions break down without invoking consciousness...The most exotic is the “many worlds” view, which says that whenever you make a quantum measurement, reality fractures, creating parallel universes to accommodate every possible outcome. Thus, Wigner’s friend would split into two copies and, “with good enough supertechnology,” he could indeed measure that person to be in superposition from outside the lab...

[DeFault User]

I asked my first philosophy prof if Berkeley’s esse est percipi could be disproved. He hemmed and coughed a bit, saying it was long and complicated,then he dismissed the class.
I’ve yet to hear it disproved.

[Reily]

I think Samuel Johnson did it when he kicked a rock!

[PTBAA]

“Am I alive or am I dead? Open the box, the suspense is killing me!”

[dp0622]

lol well now you’re getting into relativity

as in “she’s relatively ugly” before beers.

to “relatively not THAT bad” after 3 or 4.

to “relatively decent” after 5 to 7.

to “i think i’d go home with her” after 8 or 9

to “GOD I HAVE TO HAVE HER!!” at 10 or more :)

[tet68]

to “GOD I HAVE TO HAVE HER!!” at 10 or more :)

The important thing to remember is leave BEFORE
they turn the lights on at closing time.

[Political Junkie Too]

He argued it was absurd to say his friend exists in a superposition of having seen and not seen a decay unless and until Wigner opens the lab door.

But what about Wigner's boss in the next office who hasn't seen Wignor nor his friend? Is Wignor in a supersuperposition of having seen and not seen his friend measure or not measure a decay until his boss opens his door?

-PJ

[dp0622]

lol

[discostu]

Keeping in mind that the whole Schrödinger’s Cat thing exists because he didn’t like the implications of what they were saying. So he started working the math to disprove them. And wound up with the ultimate proof, kind of a “dammit they’re right”. Inevitably somebody was gonna figure out a way around it. Cause we know that’s not how stuff works in practicality. But you gotta figure out the math.

[discostu]

Right. But the question always is which version of reality are we in? And when does the wave form collapse to determine that? That’s the whole bucket behind it.