Model Black Hole Re-Creates Stephen Hawking Prediction
黑洞模型重塑霍金预言

A black hole analogue, which traps sound instead of light, generates "Hawking radiation," a key prediction by the theoretical physicist. Christopher Intagliata reports.
理论物理学家的重要预言“霍金辐射”，能够由一个吸收声音而非光线的黑洞模型产生。克里斯托弗·因塔利亚塔(Christopher Intagliata)报道。

撰文/播音：克里斯托弗·因塔利亚塔(Christopher Intagliata)
翻译：杨枭
审校：吴非

Black holes got their name because light can't escape them, beyond a certain radius—the event horizon. But in 1974 Stephen Hawking proposed that quantum effects at the event horizon might cause black holes to be…not completely black.
 “黑洞”得名于它对光线的吸收，在某个半径之内的光线无法逃离。这个半径被称为事件视界。但是在1974年，斯蒂芬·霍金提出，在事件视界处有量子效应出现，这可能使得黑洞变得不那么黑。

"Hawking said that pairs of particles should be created at the event horizon." Jeff Steinhauer, a physicist at the Israel Institute of Technology. "One particle exits the black hole and travels away, perhaps to Earth, and the other particle falls into the black hole."
来自以色列理工大学的物理学家杰夫·施泰因豪尔说：“霍金认为，成对的粒子在事件视界产生。其中一个离开黑洞去了比如地球这样的远方，另一个则跌入了黑洞。”

Ideally, we could just study those exiting particles…which make up the so-called Hawking radiation. But that signal is too weak. We can't see it against the universe's background radiation. So Steinhauer built a model of a black hole instead. Which traps not photons, but phonons—think of them as sound particles—using a gas of rubidium atoms, flowing faster than the speed of sound.
理论上来讲，我们可以研究那些离开黑洞的粒子，它们产生了霍金辐射。但是，辐射的信号太微弱了。我们无法将这些信号与宇宙微波背景辐射区分开。因此，施泰因豪尔改为制造了一个黑洞模型。该模型能捕获的不仅有光子，还有声子。在实验中，他利用一团移动快于声速的铷原子气体作为声音粒子。

"And that means that phonons, particles of sound, trying to travel against the flow are not able to go forward. They get swept back by the flow. It's like someone trying to swim against a river which is flowing faster than they can swim. And the phonon trying to go against the flow is analogous to a photon trying to escape a black hole."
“这说明，声音粒子试图逃离陷入黑洞的洪流但无法成功。它们全都被卷回黑洞。这就像是一个人试图逆着比游速更快的奔涌的水流游泳。试图逃离的声子就如同试图逃离黑洞的光子。”

Steinhauer doesn't actually pipe sound particles into the device. He doesn't need to. He merely created the conditions under which quantum effects predict their appearance. "So the two swimmers can come into existence simultaneously without anybody supplying energy to create them."
事实上，施泰因豪尔并没有向设备中输入声音粒子。他根本不需要。他仅仅创造了由量子效应预言的声子存在的环境条件。“无需任何人提供任何能量支持，两个游泳者自发地同时产生。”

He ran the test 4,600 times—the equivalent of six days—and took pictures of the results. And indeed, he saw a correlation between particles emanating into and out of the model black hole…an experimental demonstration of Hawking radiation. The results appear in Nature Physics. [Jeff Steinhauer, Observation of quantum Hawking radiation and its entanglement in an analogue black hole]
施泰因豪尔测试了4600次——相当于六天时间，然后拍下了结果的图片。他确实观察到了进出黑洞的粒子的相关性，从实验上证明了霍金辐射。该结果发表在了《自然-物理学》期刊上。

Steinhauer also determined that the partner particles had a quantum connection, called entanglement…which could help theorists investigating the information paradox. "So there's the question of where does information go, if one throws it into a black hole?" This study can't answer that. But, he says, "it helps give hints, to direct physicists towards the new laws of physics, whatever they might be."施泰因豪尔也判定了成对粒子的量子纠缠关系，这能够帮助理论物理学家研究信息悖论。“所以现在的问题是，如果信息陷入了黑洞，那它去了哪儿呢？”这项研究并不能回答这个问题，但他也表示：“这项研究为物理学家提出物理新定律给出了线索，无论全新的物理定律会多么令人惊异。”

原文链接：
https://www.scientificamerican.com/podcast/episode/model-black-hole-re-creates-stephen-hawking-prediction/

（题图来源：http://www.scientificamerican.com）