The problem goes like this, Tollaksen says: Take two radioactive atoms, so identical that “even God couldn’t see the difference between them.” Then wait. The first atom might decay a minute later, but the second might go another hour before decaying. This is not just a thought experiment; it can really be seen in the laboratory. There is nothing to explain the different behaviors of the two atoms, no way to predict when they will decay by looking at their history, and—seemingly—no definitive cause that produces these effects. This indeterminism, along with the ambiguity inherent in the uncertainty principle, famously rankled Einstein, who fumed that God doesn’t play dice with the universe.“Nature is trying to tell us that there is a difference between two seemingly identical particles with different fates, but that difference can only be found in the future,” he says. If we’re willing to unshackle our minds from our preconceived view that time moves in only one direction, he argues, then it is entirely possible to set up a deterministic theory of quantum mechanics.It bothered Aharonov as well. “I asked, what does God gain by playing dice?” he says. Aharonov accepted that a particle’s past does not contain enough information to fully predict its fate, but he wondered, if the information is not in its past, where could it be? After all, something must regulate the particle’s behavior. His answer—which seems inspired and insane in equal measure—was that we cannot perceive the information that controls the particle’s present behavior because it does not yet exist.
Man stelle sich vor: Man fuehrt ein Experiment durch, das von einer zukuenftigen Messung beeinflusst wird.
Danach bestimmt zufaellig, ob man die beeinflussende "zukuenftige" Messung durchfuehrt oder nicht und haelt sich an das Ergebnis.
In diesem Fall kann man bereits aus der ersten Messung ableiten, ob die zufaellige Entscheidung ueber das zweite Experiment positiv oder negativ ausfaellt. Die Entscheidung ist demnach nicht mehr zufaellig, sondern bereits durch das Ergebnis der ersten Messung vorgegeben.
Mindfuck!
Und die haben wirklich Experimente durchgefuehrt, die genau das zeigen:
Tollaksen and Aharonov proposed analyzing changes in a quantum property called spin, roughly analogous to the spin of a ball but with some important differences. In the quantum world, a particle can spin only two ways, up or down, with each direction assigned a fixed value (for instance, 1 or –1). First the physicists would measure spin in a set of particles at 2 p.m. and again at 2:30 p.m. Then on another day they would repeat the two tests, but also measure a subset of the particles a third time, at 3 p.m. If the predictions of backward causality were correct, then for this last subset, the spin measurement conducted at 2:30 p.m. (the intermediate time) would be dramatically amplified. In other words, the spin measurements carried out at 2 p.m. and those carried out at 3 p.m. together would appear to cause an unexpected increase in the intensity of spins measured in between, at 2:30 p.m. The predictions seemed absurd, as ridiculous as claiming that you could measure the position of a dolphin off the Atlantic coast at 2 p.m. and again at 3 p.m., but that if you checked on its position at 2:30 p.m., you would find it in the middle of the Mediterranean.
Okay, das ist noch ziemlich esoterisch, aber das Rochester-Experiment ist relativ simpel:
In the Rochester setup, laser light was measured and then shunted through a beam splitter. Part of the beam passed right through the mechanism, and part bounced off a mirror that moved ever so slightly, due to a motor to which it was attached. The team used weak measurements to detect the deflection of the reflected laser light and thus to determine how much the motorized mirror had moved.
That is the straightforward part. Searching for backward causality required looking at the impact of the final measurement and adding the time twist. In the Rochester experiment, after the laser beams left the mirrors, they passed through one of two gates, where they could be measured again—or not. If the experimenters chose not to carry out that final measurement, then the deflected angles measured in the intermediate phase were boringly tiny. But if they performed the final, postselection step, the results were dramatically different. When the physicists chose to record the laser light emerging from one of the gates, then the light traversing that route, alone, ended up with deflection angles amplified by a factor of more than 100 in the intermediate measurement step. Somehow the later decision appeared to affect the outcome of the weak, intermediate measurements, even though they were made at an earlier time.
Oder ist alles doch nur Zufall
“The future can only affect the present if there is room to write its influence off as a mistake,” Aharonov says.
Nachdem ich den ganzen Artikel gelesen habe, bin ich unschluessig:
Es scheint relativ einfach, das Ganze als selektive Wahrnehmung abzutun, aber ist es die selektive Wahrnehmung eines menschlichen Geistes, der ein Muster in den Ereignissen sehen will (unsere Wahrnehmung ist darauf programmiert, Muster zu erkennen, deshalb projezieren wir Muster in zufaellige Ereignisse), oder ist die selektive Wahrnehmung eines menschlichen Geistes, der nicht im Stande ist, ausserhalb eines linearen Ablaufs der Zeit zu denken (und die drei Zeitebenen unserer Wahrnehumng sind in Wirklichkeit ineinander verdrillt)?
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