[How to spot quantum quackery (量子いんちき医療を見抜くには) (2010/09/20)) on CosmicLog]

Q: You do see that in some science-fiction shows - for example, last season on "Fringe." And quantum mechanics is often used as the explanation for that.

A: Quantum mechanics is often quoted as the explanation for many things, because it's so weird that people latch onto it as a hope, to explain everything that they would like to believe about the universe. Everything from the possibility of disappearing and reappearing, to the possibility of having strange new forms of communication. We'd like to be able to influence things just by thinking about them, we'd like to transport ourselves elsewhere without getting on an airplane. All those things can be attributed to quantum mechanics -- first of all, because it's so poorly understood by the public, and especially because it's so verifiably weird. It's used as an excuse to be even weirder. I think of what Niels Bohr said to Wolfgang Pauli about theories that are "not crazy enough to be true." Quantum mechanics is crazy, but it's just crazy enough to make the world still be sensible at a macroscopic level, the level that we experience.

It's truly amazing that you can separate two elementary particles that were originally tied together, and often make a measurement of one particle that instantly affects the other, even if it's on Alpha Centauri. That sounds like magic. There are lots of things in quantum mechanics that sound like magic. But sounding like magic and being magic are two different things.

Cosmic Log: "Fringe"のラストシーズンのようなSF番組を見ていると思う。そして、それらでは、その説明に量子力学が多用されているのを。

Lawrence Krauss: 量子力学が多くの物事の説明に使われる。これは、量子力学があまりに奇妙なので、人々が宇宙について信じたいことなら何でも説明できるのだという望みを持っていて、手放せないからだ。消失と再出現の可能性から、奇妙な新たな通信手段の可能性まで、どんなものでも。我々は、物体について考えるだけで、その物体に影響を与えることができるようになりたいと思っている。そして、我々は航空機の乗らずに、どこにでも行きたいと思っている。それらすべてを量子力学のせいにできるのは、まずもって、一般人が量子力学をほとんど理解しておらず、特に検証可能な奇妙さについてわかっていないからだ。ニールス・ボーアがパウリに「正しくなるにはクレージーさが足りない」理論について語ったことを思い出す。量子力学はクレージーだが、マクロレベル、すなわち我々が経験するレベルで、世界を認識できる程度にクレージーだ。


Q: Obviously, quantum mechanics has lots of real-life applications, including in your television set and your microwave oven. But are there new, weird applications that people might see that have an impact on everyday life, beyond the woo-woo?

A: Absolutely. One has already been recognized: If we do carefully prepare quantum systems, and keep them isolated, we can perform quantum magic technologically ? potentially on scales that we haven't been able to do before. We might be able to create quantum computers, for example, that will simultaneously do many different calculations at once, because the quantum world is capable of doing many things at the same time. We may be able to use quantum communication in ways that we haven't done before.

The debate here is that we'll be able to use quantum mechanics to break codes, in particular to determine the big prime numbers that are at the basis of the security of your credit cards and your bank cards. Right now they use a key that's based on the products of large prime numbers, and no computer could determine the prime factors in a time shorter than the age of the universe. But quantum-mechanical computers might be able to, and then of course we'd have to start thinking about how to make things more secure.

The flip side of that is that you can use quantum mechanics, again in specially prepared systems, to communicate in a way that will allow us to know when someone is eavesdropping. So on one hand you have a threat to security, and on the other you have a possible boon for security. We don't know which way it's going to go.

One other area where quantum mechanics works on a macroscopic scale is in superconductivity and superfluidity. Those are two places where the quantum world leaks into the classical world. We're not using either superconductivity or superfluidity yet on the scale that I think people thought we might. But we're certainly using them at the Large Hadron Collider, which we couldn't even operate if we didn't have superconducting magnets.

So when you hear about quantum mechanics and devices, you can say, "OK, that sounds reasonable." But when you hear about quantum mechanics and consciousness, you should assume the author is a crackpot unless proven otherwise. Moreover, assume that they want your money. ...

Cosmic Log: テレビや電子レンジなど、量子力学の応用されたものが実生活には多くある。しかし、日々の生活に影響を与えるような新たな奇妙な応用例があるだろうか?

Lawrence Krauss: もちろんだ。ひとつは既に知られているものだ。もし我々が注意深く量子システムを準備できて、それを外界から孤立させられれば、原理的には我々は量子の魔法を技術的に実行できる。我々は、たとえば、異なる計算を同時に実行できる量子コンピュータを作れるかもしれない。というのは、量子世界では、多くのことが同時に起きるからだ。また、我々はこれまでに実現したことがない方法で、量子通信を可能にできるかもしれない。





Q: Why do you think that people have seized upon this? I guess it's a sign that quantum physics is entering the mainstream...

A: Well, yeah, the point is that there have been these new-age desires for lots of things to make the world better: crystals, energy vortices. ... People latch onto their dreams, and they always try to match them to reality. Quantum mechanics is a replacement for the phrase "anything goes." Once anything goes, you can have anything you want. So what better thing to have than something that gives you everything you want? The point is, with quantum mechanics, everything doesn't go. On certain scales, for certain times, in certain regions, everything goes and strange things happen. But it's not true for the universe at large.

Often, people who are trying to sell whatever it is they're trying to sell try to justify it on the basis of science. Everyone knows quantum mechanics is weird, so why not use that to justify it? ... I don't know how many times I've heard people say, "Oh, I love quantum mechanics because I'm really into meditation, or I love the spiritual benefits that it brings me." But quantum mechanics, for better or worse, doesn't bring any more spiritual benefits than gravity does.

Cosmic Log: 何故、人々は量子力学に心を奪われるのだろうか? それは量子力学がメインストリームに入ってきたという徴候ではないだろうか。

Lawrence Krauss: いや、まあ、ポイントは、クリスタルとかエネルギーボルテックスとか、世界を良くする多くの物へのニューエイジの欲望があることだ。人々は夢にとらわれ、その夢を現実と一致させようとする。量子力学は「何でもアリ」の言い換え表現である。何でもアリになれば、望むものは何でも手にできる。望む物を何でも与えてくれる何か、よりも良いものは何だろうか。量子力学についてポイントは、何でもアリではないことだ。特定の空間スケールと時間スケールと特定の場所では、何でもアリで奇妙なことが起きる。しかし、大規模な宇宙では、それは成立しない。


このあとは、Lawrence KraussによるScientific American掲載記事へつづく...

posted by Kumicit at 2010/09/26 06:25 | Comment(0) | TrackBack(0) | Quackery | このブログの読者になる | 更新情報をチェックする



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