Friday, October 16, 2009


今年3月3日写的博文,提到当年一位咏春拳友向我介绍的量子力学实验,今天在BBC的一篇文章里看到了关于这种实验以及这种现象的深入浅出的说明,黏贴如下:

TELEPORTATION

The theory: Going from here to somewhere else without passing through anywhere in between.

The science fiction: Beam me up, Scotty.

In practice: Take two particles of light and entangle them - now you can teleport quantum information - such as what their spin is - from one to the other, instantaneously.

The layman's explanation: Photons, particles of light, have a property called "spin". This can be up, down, or a mixture of the two. Alice has a photon, and she wants Bob to have one with the same spin. She can't send him hers because the Post Office is on strike, and she can't measure her spin and phone him, because the measurement can change the spin.

Fortunately, the last time she met Bob she gave him one photon from an entangled pair, and kept the other. "Entangled" means that the two photons were prepared so that their states were related in a special way. Alice lets her photon interact with her other photon from the entangled pair. This instantly teleports information about the spin to Bob's half. However, he can't "read" that information until a message arrives by more conventional means. A quick call on Alice's mobile, telling him some measurements she has made, now puts his entangled photon into the desired state.

Quantum "teleportation" destroys the original state and can't be used to send messages faster than light. It doesn't actually teleport matter - just quantum information.

Coming to a store near you?: In 1998, the quantum optics group at Caltech used "squeezed light" to teleport the state of a photon in a laboratory. It's now been done with atoms, too. In 2004 Austrian physicists teleported the state of a photon across the Danube river. Within another century it will be an amoeba. But be warned: when you are teleported, your body will be ripped to shreds and rebuilt at the other end.


Sunday, October 04, 2009


to traumatise

如果是指造成精神上的“创伤”,在英汉词典里普遍都缺了一个对应词:“刺激”。当然“刺激”的语义范围更广,但其中有一个义项是完全可以对应traumatise的。另一个比较贴切的对应词是“打击”,但很多词典也没列出。