液晶中的魔法 | 諾獎得主Wilczek專欄_風聞
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作者 | Frank Wilczek (麻省理工學院教授、2004年諾貝爾獎得主）
翻譯 | 梁丁當**、胡風**
來源：蔻享學術
當我們學到掌控物理世界的新方法時，魔法就會降臨。很多科技放到一百年前完全就是魔法，比如，核能、磁共振成像和GPS，它們都來自神奇的量子世界。那麼現代魔法在哪裏呢？
製造顯示屏的神奇材料擁有創造未來技術的驚人潛力。
The uncanny material in your TV display may hold astonishing potential for creating future technologies.
物理學中最吸引人的領域或許是宇宙學和那些尋找新基本定律的研究。但除此之外，還有一個前沿領域也是非常有意思的，那就是尋求魔法。當然，我指的不是騙人的小把戲，而是科幻作家亞瑟·C·克拉克（Arthur C. Clarke）所詮釋的那種魔法——他有個著名的定律：“任何足夠先進的科技，皆與魔法無異。”
The most glamorous fields in physics are probably cosmology and the search for new fundamental laws. While those subjects are glorious, there’s also another frontier to relish: the pursuit of magic. Of course, here I don’t mean trickery but magic in the spirit of the science-fiction writer Arthur C. Clarke’s famous law: “Any sufficiently advanced technology is indistinguishable from magic.”
每當我們學到掌控物理世界的新方法時，魔法就會降臨。很多科技放到一百年前完全就是魔法，比如，核能、磁共振成像和GPS，它們都來自神奇的量子世界。
This kind of magic happens when we learn new ways to control the physical world. Many technologies that would have seemed utterly magical a hundred years ago—including nuclear energy, magnetic resonance imaging and GPS—have bubbled up from the quantum world.
可是現代魔法還有另外一個分支，它的源頭不像量子力學那樣顯赫，至今沒有受到足夠的重視，還有非常巨大的潛力尚未發揮出來。你可以從肥皂盒裏粘糊糊的殘漬中隱約察覺到它的蛛絲馬跡。基礎科學課常常宣稱物質有三態：固態、液態和氣態，然而自然界中的物態遠比這豐富。這種黏性物質就屬於三態之外的另一種物態：液晶。
But there’s another branch of modern magic, underappreciated and still vastly underdeveloped, that has humbler origins. You can see a hint of it in the gooey residue left behind in your soapdish. Elementary science classes advertise three “states of matter”—solid, liquid and gas—but that barely scratches the surface of what’s out there. That goo is something else: a liquid crystal.
液晶是一種既能像液體一樣流動，又能像晶體一樣與光發生相互作用的獨特物態。它們通常由較長的有機分子構成。液晶的奇妙之處在於，一方面這些分子定向排列成某種規則的圖案，而另一方面它們的中心卻可以自由移動。這些方向固定的分子就像一個個小的電磁波接收天線，可以吸收光，並將其轉換成另外的形式。
Liquid crystals, which flow like liquids but interact with light like crystal, are a distinct phase of matter. They are usually made from long organic molecules. Their basic secret is that those molecules are oriented in regular patterns, while their centers can move freely. The oriented molecules act like little antennas for the electromagnetic waves we see as light. They absorb those waves and then retransmit them in altered forms.
由於液晶兼有晶體改變光的能力與液體的流動性，它們可以用於製作超柔韌、對顏色敏感的稜鏡和偏振片。這使得它們在顯示器製造方面極為有用。實際上，液晶是絕大多數現代計算機顯示屏的核心材料。
Because liquid crystals combine light-altering properties with fluidity, they can provide ultra-flexible, color-sensitive lenses and polarizers. This makes them tremendously useful for building visual displays. Indeed, liquid crystals are central players in most modern computer screens.
液晶的數學理論融合了晶體複雜的對稱性與流體豐富的動力學，並進一步分析了這些因素對液晶的光學特性有怎樣的影響。1991年，法國物理學家皮埃爾-吉勒·德熱納（Pierre-Gilles de Gennes）因其對液晶理論的貢獻榮獲諾貝爾物理學獎。
The mathematical theory of liquid crystals combines the intricate symmetry of crystalline patterns with the dynamical richness of liquid flows and then examines how these elements interact with light. In 1991, Pierre-Gilles de Gennes won the Nobel Prize in Physics for his contributions to that theory.
然而我們對液晶的理解還遠不止於此，更神奇的是，液晶還是生命的核心。有一種特殊的二維液晶，它捲曲形成閉合球面，組成了細胞表面以及細胞內不同功能單元之間的薄膜。這些液晶能選擇性地讓各類不同物質通過，從而讓細胞可以進食、消化、排泄與呼吸。它們還會生長、發芽和分裂，而這些活動正是生物發育與繁殖的根本基礎。
Yet when it comes to our understanding of liquid crystals, the best is yet to come. In fact, liquid crystals are central to life itself. A special kind of twodimensional liquid crystal, closed up into sphere-like surfaces, forms the membranes that define the boundaries of cells and of functional units within cells. These crystals can selectively dissolve complex protein molecules, thus accommodating cellular eating, digestion, excretion and respiration. They can also grow, bud and fission—activities that are the soul of biological development and reproduction.
在這方面，人類的工程師還遠不及大自然。我們的機器不會複製、生長和自我修復，在調控與環境的互動時，也遠達不到生物那般的精妙複雜。人類發展液晶技術的主要瓶頸是：儘管我們有描述液晶的出色方程，卻並不擅長利用它來指導創新設計。
Human engineers haven’t caught up to nature’s skill in this medium. Our machines don’t reproduce, develop, heal or regulate intercourse with their environment with anything approaching the sophistication of biology. A major bottleneck is that although we have good equations for liquid crystals, we’re not yet good at using those equations to guide creative design.
這個問題可能太複雜了，以至於超越了我們大腦本身的能力。而邊做邊學（或更準確地説，邊模擬邊學）的計算機程序則很可能勝過我們人類的邏輯推導，幫我們獲得更多的成功設計。技術就是這樣進步的：今天的魔法會孕育出明天的魔法。
This problem may be too complicated for unaided human brains. It seems likely that computer algorithms, which learn by doing (or, more accurately, by simulating), will yield more successful designs than conventional human logic. In this way, today’s magic will conjure up tomorrow’s.
作者簡介：**Frank Wilczek：**弗蘭克·維爾切克是麻省理工學院物理學教授、量子色動力學的奠基人之一。因在夸克粒子理論（強作用）方面所取得的成就，他在2004年獲得了諾貝爾物理學獎。
本文經授權轉載自微信公眾號「蔻享學術」。
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