※ [本文轉錄自 Gossiping 看板 #1OSKcHzk ] 作者: prime2477 (12345678901234567890123) 看板: Gossiping 標題: [新聞] 三狹縫實驗發現 奇異彎曲的光軌跡 時間: Sun Jan 8 04:03:22 2017 1.媒體來源: Phys.org 2.完整新聞標題: Physicists detect exotic looped trajectories of light in three-slit experiment 物理學家從三狹縫實驗中發現 奇異彎曲的光軌跡 3.完整新聞內文: January 6, 2017 by Lisa Zyga http://imgur.com/88NumP2.jpg The red path shows an exotic looped trajectory of light through a three-slit structure, which was observed for the first time in the new study. Credit: Magaña-Loaiza et al. Nature Communications 圖中的紅線顯示出，奇異彎曲的光軌跡穿過三狹縫結構，這是第一次從實驗中觀測到這種 現象。來源: Magaña-Loaiza et al. Nature Communications (Phys.org)—Physicists have performed a variation of the famous 200-year-old double-slit experiment that, for the first time, involves "exotic looped trajectories" of photons. These photons travel forward through one slit, then loop around and travel back through another slit, and then sometimes loop around again and travel forward through a third slit. (Phys.org)—物理學家已經演示了著名的且有200年歷史的雙狹縫實驗，但這是第一次涉 及光子的"奇異彎曲軌跡"。這些光子穿過第一道狹縫後，轉彎倒車穿過第二道狹縫，然後 再轉彎迴正穿過第三道狹縫。 Interestingly, the contribution of these looped trajectories to the overall interference pattern leads to an apparent deviation from the usual form of the superposition principle. This apparent deviation can be understood as an incorrect application of the superposition principle—once the additional interference between looped and straight trajectories is accounted for, the superposition can be correctly applied. 有趣的是，這些彎曲軌跡，對總干涉圖形的貢獻，與疊加原理的常見形式比較，有明顯的 誤差。該明顯誤差可以理解為不正確地使用疊加原理 - 一旦考慮了彎曲和直線軌跡之間 的附加干擾，則可以正確地應用疊加原理。 The team of physicists, led by Omar S. Magaña-Loaiza and Israel De Leon, has published a paper on the new experiment in a recent issue of Nature Communications. 由 Omar S.Magaña-Loaiza 與以色列 De Leon 領導的物理學家團隊，在最近一期的 Nature Communications 上，發表了一篇關於新實驗的論文。 Loops of light 彎曲的光 "Our work is the first experimental observation of looped trajectories," De Leon told Phys.org. "Looped trajectories are extremely difficult to detect because of their low probability of occurrence. Previously, researchers had suggested that these exotic trajectories could exist but failed to observe them." De Leon 向 Phys.org 表示，"我們的成果是第一個從實驗中觀察到彎曲軌跡"。"彎曲軌 跡極難探測，因為它們發生的機率很低。在過去，研究者曾提出這些奇異的軌跡可能存在 ，但未能觀察到它們。" To increase the probability of the occurrence of looped trajectories, the researchers designed a three-slit structure that supports surface plasmons, which the scientists describe as "strongly confined electromagnetic fields that can exist at the surface of metals." The presence of these electromagnetic fields near the three slits increases the contribution of looped trajectories to the overall interference pattern by almost two orders of magnitude. 為了增加彎曲軌跡發生的機率，研究者設計了提供表面電漿子的三狹縫結構，科學家將其 描述為"可存在於金屬表面的強限制電磁場"。在三狹縫附近的電磁場，增加了彎曲軌跡對 整體干涉圖形的貢獻，幾乎兩個數量級。 "We provided a physical explanation that links the probability of these exotic trajectories to the near fields around the slits," De Leon said. "As such, one can increase the strength of near fields around the slits to increase the probability of photons following looped trajectories." De Leon 表示"我們提供了一個物理解釋，將這些奇異軌跡的機率連繫到狹縫周圍的近場 。因此，增加狹縫周圍近場的強度，可以增加光子走彎曲軌跡的機率。" Superposition principle accounting for looped trajectories 考慮彎曲軌跡的疊加原理 The new three-slit experiment with looped trajectories is just one of many variations of the original double-slit experiment, first performed by Thomas Young in 1801. Since then, researchers have been performing versions that use electrons, atoms, or molecules instead of photons. 有彎曲軌跡的新三狹縫實驗，是原始雙狹縫實驗的許多變種之一。最初的雙狹縫實驗由 Thomas Young 在1801年進行。從那時起，研究人員一直在使用電子, 原子或分子代替光 子。 One of the reasons why the double-slit experiment has attracted so much attention is that it represents a physical manifestation of the principle of quantum superposition. The observation that individual particles can create an interference pattern implies that the particles must travel through both slits at the same time. This ability to occupy two places, or states, at once, is the defining feature of quantum superposition. 雙狹縫實驗引起了這麼多關注的原因之一是，它證明了量子疊加原理。各別的粒子可以產 生干涉圖形的觀察結果，意味著粒子必須同時穿過兩個狹縫。這種同時佔據兩個地方或狀 態的能力是量子疊加的特徵。 http://imgur.com/4wEv3Z6.jpg Straight trajectories (green) and exotic looped trajectories (red, dashed, dotted) of light, where the red cloud near the surface depicts the near fields, which increase the probability of photons to follow looped trajectories. The graphs at left show simulations (top) and experimental results (bottom) of the large difference in interference patterns created by illuminating only one slit being treated independently (gray line) and the actual coupled system (blue line). The remarkable difference between the gray and blue lines is caused by the looped trajectories. Credit: Magaña-Loaiza et al. Nature Communications 光的直線軌跡(綠色)和奇異彎曲軌跡(紅色, 虛線, 虛線)。其中表面附近的紅雲描繪了近 場，這增加了光子走彎曲軌跡的機率。右側的圖為模擬(上)與實驗(下)的干涉圖形，顯示 了單獨處理照射一個狹縫(灰線)與實際耦合系統(藍線)的巨大差異。灰線和藍線之間的顯 著差異是由彎曲軌跡造成的。來源: Magaña-Loaiza et al. Nature Communications So far, all previous versions of the experiment have produced results that appear to be accurately described by the principle of superposition. This is because looped trajectories are so rare under normal conditions that their contribution to the overall interference pattern is typically negligible, and so applying the superposition principle to those cases results in a very good approximation. 迄今為止，所有先前版本的實驗，可以用疊加原理精確地描述實驗結果。這是因為在正常 條件下，彎曲軌跡是非常罕見的，使得它們對整體干涉圖形的貢獻通常可忽略，並且可用 疊加原理去解釋那些情況。 It is when the contribution of the looped trajectories becomes non-negligible that it becomes apparent that the total interference is not simply the superposition of individual wavefunctions of photons with straight trajectories, and so the interference pattern is not correctly described by the usual form of the superposition principle. 當彎曲軌跡的貢獻變得不可忽略時，很明顯地，總干涉圖形不是由各別的直線軌跡光子的 波函數疊加，因此干涉圖形不能以疊加原理的通常形式來解釋。 Magaña-Loaiza explained this apparent deviation in more detail: Magaña-Loaiza 更詳細地解釋了這種明顯的誤差: "The superposition principle is always valid—what is not valid is the inaccurate application of the superposition principle to a system with two or three slits," he said. 他表示: "疊加原理一直是正確的，不正確的是，錯誤的使用疊加原理在兩個或三個狹縫 系統"。 "For the past two centuries, scientists have assumed that one cannot observe interference if only one slit is illuminated in a two- or three-slit interferometer, and this is because this scenario represents the usual or typical case. 在過去的兩個世紀裡，科學家們認為，如果在雙或三狹縫干涉儀中，只有一個狹縫被照射 ，那麼人們不能觀察到干涉，這是因為這種情況代表了通常或典型的情況。 "However, in our paper we demonstrate that this is true only if the probability of photons to follow looped trajectories is negligible. Surprisingly, interference fringes are formed when photons following looped trajectories interfere with photons following straight (direct) trajectories, even when only one of the three slits is illuminated. "然而，在我們的論文中，我們證明只有當光子走彎曲軌跡的機率可忽略時，這種情況才 是對的。出乎意料的是，即使三個狹縫中只有一個被照射，走彎曲軌跡的光子會干涉走直 線軌跡的光子，形成干涉條紋。" "The superposition principle can be applied to this surprising scenario by using the sum or 'superposition' of two wavefunctions; one describing a straight trajectory and the other describing looped trajectories. Not taking into account looped trajectories would represent an incorrect application of the superposition principle. "疊加原理可以解釋這種令人驚奇的情況，透過使用兩個波函數的和或'疊加'; 一個波函 數描述直線軌跡的光子，另一個描述彎曲軌跡的。不考慮彎曲軌跡會使疊加原理失效。" "To some extent, this effect is strange because scientists know that Thomas Young observed interference when he illuminated both slits and not only one. This is true only if the probability of photons following looped trajectories is negligible." "在某種程度上，這種結果是很奇怪的，因為科學家知道 Thomas Young 是照射兩個狹縫 ，才觀察到干涉，而不是一個。但是這只在彎曲軌跡光子的機率可以忽略時，才是對的。 " In addition to impacting physicists' understanding of the superposition principle as it is applied to these experiments, the results also reveal new properties of light that could have applications for quantum simulators and other technologies that rely on interference effects. 除了影響物理學家用疊加原理解釋這些實驗，其結果還揭示了光的新性質，該性質可能用 於量子模擬器與其它使用干涉效應的技術。 "We believe that exotic looped paths can have important implications in the study of decoherence mechanisms in interferometry or to increase the complexity of certain protocols for quantum random walks, quantum simulators, and other algorithms used in quantum computation," De Leon said. De Leon 表示，"我們認為奇異彎曲路徑可能在干涉測量的去相干機制研究中具有重要的 意義，或是增加一些已知方法的複雜度，像是量子隨機漫步, 量子模擬器, 和用於量子計 算的其他演算法"。 4.完整新聞連結 (或短網址): https://goo.gl/lEkPLA 5.備註: 原始論文 Exotic looped trajectories of photons in three-slit interference http://www.nature.com/articles/ncomms13987 疊加原理 - 維基百科，自由的百科全書 https://zh.wikipedia.org/zh-tw/%E5%8F%A0%E5%8A%A0%E5%8E%9F%E7%90%86 態疊加原理 - 維基百科，自由的百科全書 https://zh.wikipedia.org/wiki/%E6%80%81%E5%8F%A0%E5%8A%A0%E5%8E%9F%E7%90%86 --

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