【“ Quantum gas goes below absolute zero ”一文，对应科学网上《 科学家造出低于绝对零度的量子气体 》一文，有大量网友留言，认为是国内记者瞎翻；同时也有肖建华教授对此文英文原文滥用概念的分析，但是又有许多网友对肖教授的批判有质疑，并为nature说好话。故此，本文将Nature上原文照录如下，逐段翻译和评论，以说明国内记者未曾乱翻，而英文文章本身就在误导读者。为清楚记，以下英文原文用黑字，翻译用篮字，评论用红字。】 Quantum gas goes below absolute zero Ultracold atoms pave way for negative-Kelvin materials. 【翻译】量子气体降至绝对零度以下 超冷原子迈向负开尔文物质 【点评】从题目看，有物质确实降到了热力学绝对零度以下，有两个暗示：“below”表示确实是降到了“绝对零度”以下，Kelvin暗示这个温度肯定是以热力学温度定义的。我本人开始看题目的时候，就是这么认为，被骗进去读这篇文章。因为说“负温度”，则是一个老现象，没什么吸引力，我肯定不会去读。 Zeeya Merali 03 January 2013 It may sound less likely than hell freezing over, but physicists have created an atomic gas with a sub-absolute-zero temperature for the first time 1 . Their technique opens the door to generating negative-Kelvin materials and new quantum devices, and it could even help to solve a cosmological mystery. 【翻译】可能没有地方冷过地狱，但物理学家们首次创造比绝对零度温度还低的原子气体。这项技术打开了通向负开尔文物质和新量子器件的大门，并有助于解开宇宙学中的一个奥秘。 【点评】煽情！使我感到了少年时读《飞碟探索》时那久违了的激情。而cosmological还暗示了“宇宙起源”的意思，顿时激起了我的好奇心。 Lord Kelvin defined the absolute temperature scale in the mid-1800s in such a way that nothing could be colder than absolute zero. Physicists later realized that the absolute temperature of a gas is related to the average energy of its particles. Absolute zero corresponds to the theoretical state in which particles have no energy at all, and higher temperatures correspond to higher average energies. 【翻译】卡尔文勋爵在19世纪中期定义了绝对温标，在其定义的方式中，没有物质可以冷过绝对零度。物理学家后来认识到气体的绝对温度和构成气体的粒子的平均能量有关系。绝对零度对应于粒子完全没有能量的状态，而较高的温度对应较高的粒子的平均能量。 【点评】整段讲法，除了没给“气体”加上"理想"以外，好像没什么大问题。前面先使用热力学，后面偷偷摸摸地引入了经典统计力学，而特别强调“平均能量”。如果你不注意，不会注意到这里“平均能量”会暗示有为“负能量”或者"暗能量"做准备的情况。 当然严格讲来，如果没有使用理想气体模型，对于考虑量子力学的情况，就不能说绝对零度时粒子能量为零的话；另则对于一个物质体系而言，我们一般使用温度和体系粒子的平均动能相联系，而不是直接说"能量".因为对于经典力学所描述的系统，“能量”既包括动能还包括势能。 However, by the 1950s, physicists working with more exotic systems began to realise that this isn't always true: Technically, you read off the temperature of a system from a graph that plots the probabilities of its particles being found with certain energies. Normally, most particles have average or near-average energies, with only a few particles zipping around at higher energies. In theory, if the situation is reversed, with more particles having higher, rather than lower, energies, the plot would flip over and the sign of the temperature would change from a positive to a negative absolute temperature, explains Ulrich Schneider, a physicist at the Ludwig Maximilian University in Munich, Germany. 【翻译】然而，到了1950年代，与奇异系统打交道的物理学家们开始意识到这种讲法并不总是真实的-从技术上讲，你总是从一张概率图上读取一个体系的温度，这张概率图上画上了在特定能级上找到粒子的概率。正常情况下，大多数粒子具有平均的或者接近平均的能量，只有少数粒子在高的能级附近来回快速变动。理论上讲，如果情况倒过来，更多的粒子处于高的能量状态，而相对少量粒子处于低的能态，这张概率图就会颠倒过来，绝对温度的符号就会从正号变成负号，得到负的绝对温度。 德国慕尼黑的 Ludwig Maximilian 大学的物理学家 Ulrich Schneider做了以上解释。 【点评】以上解释，除了“ 大多数粒子具有平均的或者接近平均的能量”非常不严格（正确的说法应该是：一般情况下，低能态的粒子数多，高能态的粒子数少。B-S分布是： ；Fermi-Dirac分布是： ；Bolzmann分布是： ），其余都没啥问题。但是以上巧妙在于“ this isn't always true”，一下子就从热力学的温度定义跳到了统计力学的温度定义，偷偷地转换了概念，一般人还看不出来，懂得的人也不能说这种讲法有错。以后我写文章，一定要学习：I'm a gentleman.But this is not always true. Peaks and valleys 【翻译】山峰和山谷 Schneider and his colleagues reached such sub-absolute-zero temperatures with an ultracold quantum gas made up of potassium atoms. Using lasers and magnetic fields, they kept the individual atoms in a lattice arrangement. At positive temperatures, the atoms repel, making the configuration stable. The team then quickly adjusted the magnetic fields, causing the atoms to attract rather than repel each other. “This suddenly shifts the atoms from their most stable, lowest-energy state to the highest possible energy state, before they can react,” says Schneider. “It’s like walking through a valley, then instantly finding yourself on the mountain peak.” 【翻译】 Schneider和他的同事们使用钾原子制造的超冷量子气体到达了这样的绝对零度以下的温度。使用激光和磁场，他们使原子按格子排列。在正温度情况下，原子们相互排斥，使结构稳定。研究团队快速调整磁场，引起原子们相互吸引的情况胜过相互排斥的情况。“这样就使得原子们在反应过来以前，从最稳定的最低的能态变到了最高的可能的能量状态。”Schneider说，“这就好比你在山谷里穿行，却突然发现自己站到了山顶。”（ 地震吗？实在忍不住要评论一下，写得太好了 ） 【点评】就实验而言，确实漂亮。 At positive temperatures, such a reversal would be unstable and the atoms would collapse inwards. But the team also adjusted the trapping laser field to make it more energetically favourable for the atoms to stick in their positions. This result, described today in Science 1 , marks the gas’s transition from just above absolute zero to a few billionths of a Kelvin below absolute zero. 【翻译】在正温度情况下，这样的翻转是不稳定的，因为原子们将向内坍塌。但是研究团队们调整了用于粒子捕捉的激光场，使其能量最为合适以将原子们定在他们的位置上。今天的Science描述道，这一结果标志着气体从绝对零度以上转变到了绝对零度以下几个纳K。 【点评】“零度以下”名正言顺地冒出来了。但是激光早已出现，“负温度”本身不算个新鲜事。所谓"妙笔生花",如此如此。 Wolfgang Ketterle, a physicist and Nobel laureate at the Massachusetts Institute of Technology in Cambridge, who has previously demonstrated negative absolute temperatures in a magnetic system 2 , calls the latest work an “experimental tour de force”. Exotic high-energy states that are hard to generate in the laboratory at positive temperatures become stable at negative absolute temperatures — “as though you can stand a pyramid on its head and not worry about it toppling over,” he notes — and so such techniques can allow these states to be studied in detail. “This may be a way to create new forms of matter in the laboratory,” Ketterle adds. 【点评】这段就不翻了，就是说找位大牛来说“牛”而已，这个我会。 If built, such systems would behave in strange ways, says Achim Rosch, a theoretical physicist at the University of Cologne in Germany, who proposed the technique used by Schneider and his team 3 . For instance, Rosch and his colleagues have calculated that whereas clouds of atoms would normally be pulled downwards by gravity, if part of the cloud is at a negative absolute temperature, some atoms will move upwards, apparently defying gravity 4 . 【点评】这段也不翻了，“好像挑战重力”，比如像我这样的爱吹牛的也喜欢这样说。 Another peculiarity of the sub-absolute-zero gas is that it mimics 'dark energy', the mysterious force that pushes the Universe to expand at an ever-faster rate against the inward pull of gravity. Schneider notes that the attractive atoms in the gas produced by the team also want to collapse inwards, but do not because the negative absolute temperature stabilises them. “It’s interesting that this weird feature pops up in the Universe and also in the lab,” he says. “This may be something that cosmologists should look at more closely.” 【翻译】绝度零度以下的气体另一个吸引眼球的地方是它酷似"暗能量",那个对抗万有引力而使宇宙加速膨胀的神秘力量。 Schneider说明他们搞出来的相互吸引的原子们想向内坍塌，但没玩成，因为负绝对温度把原子们稳住了。他说：“这古灵精怪的性质在宇宙中和我们的实验室中冒出来，着实有趣。宇宙学家们，你们肿么看？” 【点评】“暗能量”来了，元芳，你怎么看？ 【总评】绝口不提平衡态，非平衡态这些老套的概念，这种写法，我会，小学语文老师就教过。我觉得误导是好事，重要的是应该煽情耍帅玩暧昧，这篇文章都齐了。记住几个关键点;1.below;2.hell；3.average energy；4.dark energy；5.cosmology。
标签: 耍帅
