The Future Can Impact The Present?

Not all people who come here may be science minded, and some of this might be fairly uncomfortable material to absorb.  However, the author has done a superb job of making some very fuzzy and complex concepts manageable.

It is a very long article, but it is well worth the 30 minutes it takes to read it.  I will excerpt below for context, with a link to follow.

Tollaksen’s group is looking into the notion that time might flow backward, allowing the future to influence the past. By extension, the universe might have a destiny that reaches back and conspires with the past to bring the present into view. On a cosmic scale, this idea could help explain how life arose in the universe against tremendous odds. On a personal scale, it may make us question whether fate is pulling us forward and whether we have free will.

…snip….

That belief crumbled when experiments began to reveal the indeterministic effects of quantum mechanics—for instance, in the radioactive decay of atoms. 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.

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.

“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.

…snip…

By the late 1980s, Aharonov had seen a way out: He could study the system using so-called weak measurements. (Weak measurements involve the same equipment and techniques as traditional ones, but the “knob” controlling the power of the observer’s apparatus is turned way down so as not to disturb the quantum properties in play.) In quantum physics, the weaker the measurement, the less precise it can be. Perform just one weak measurement on one particle and your results are next to useless. You may think that you have seen the required amplification, but you could just as easily dismiss it as noise or an error in your apparatus.

The way to get credible results, Tollaksen realized, was with persistence, not intensity. By 2002 physicists attuned to the potential of weak measurements were repeating their experiments thousands of times, hoping to build up a bank of data persuasively showing evidence of backward causality through the amplification effect.

Just last year, physicist John Howell and his team from the University of Rochester reported success. 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.

This amazing result confirmed a similar finding reported a year earlier by physicists Onur Hosten and Paul Kwiat at the University of Illinois at Urbana-Champaign. They had achieved an even larger laser amplification, by a factor of 10,000, when using weak measurements to detect a shift in a beam of polarized light moving between air and glass.

…snip…

The free will issue is something that Tollaksen has been tackling mathematically with Popescu. The framework does not actually suggest that people could time-travel to the past, but it does allow a concrete test of whether it is possible to rewrite history. The Rochester experiments seem to demonstrate that actions carried out in the future—in the final, postselection step—ripple back in time to influence and amplify the results measured in the earlier, intermediate step. Does this mean that when the intermediate step is carried out, the future is set and the experimenter has no choice but to perform the later, postselection measurement? It seems not. Even in instances where the final step is abandoned, Tollaksen has found, the intermediate weak measurement remains amplified, though now with no future cause to explain its magnitude at all.

I put it to Tollaksen straight: This finding seems to make a mockery of everything we have discussed so far.

Tollaksen is smiling; this is clearly an argument he has been through many times. The result of that single experiment may be the same, he explains, but remember, the power of weak measurements lies in their repetition. No single measurement can ever be taken alone to convey any meaning about the state of reality. Their inherent error is too large. “Your pointer will still read an amplified result, but now you cannot interpret it as having been caused by anything other than noise or a blip in the apparatus,” he says.

In other words, you can see the effects of the future on the past only after carrying out millions of repeat experiments and tallying up the results to produce a meaningful pattern. Focus on any single one of them and try to cheat it, and you are left with a very strange-looking result—an amplification with no cause—but its meaning vanishes. You simply have to put it down to a random error in your apparatus. You win back your free will in the sense that if you actually attempt to defy the future, you will find that it can never force you to carry out postselection experiments against your wishes. The math, Tollaksen says, backs him on this interpretation: The error range in single intermediate weak measurements that are not followed up by the required post­selection will always be just enough to dismiss the bizarre result as a mistake.

OK, so I excerpted a lot.  🙂

Source

In essence, the implications are that the futures effects ripple into the past, effecting time frames in a sort of reverse causation.  This is quite a curiosity, as it gives us a glimpse into a mechanism for traversing time.

And the concept of time flowing in reverse (with our perception causing the seeming forward movement of temporal flow) is not new by any stretch.  But this is the first time that a viable experiment has been created and executed to test the very, very strange theory.

But philosophically, as mentioned, the “deterministic” argument begins to gain some traction.  I like the eloquence with which he stated his mathematical solution to the issue, in that predetermination may occur, but it is on a scale that is consistently relegated to statistical chance.  This explanation seems more like a hope and a prayer, until further study is done (if they can even craft an experiment to proof the current experiment).  But, that same further study will need to be done just to get a grip on the entire concept.

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