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Is teleportation possible?
瞬間移動有可能嗎?
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Could a baseball transform into something like a radio wave,
棒球可以先轉變成電磁波之類的東西,
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travel through buildings,
穿越建築物,
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bounce around corners,
碰撞後反彈,
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and change back into a baseball?
再變回棒球嗎?
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Oddly enough, thanks to quantum mechanics, the answer might actually be yes.
很神奇地,根據量子力學,或許真的可行
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Sort of.
大概啦
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Here's the trick.
秘密是這樣的
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The baseball itself couldn't be sent by radio,
棒球本身無法由電磁波傳送,
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but all the information about it could.
但有關它的所有資訊可以
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In quantum physics, atoms and electrons
量子物理中,原子和電子
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are interpreted as a collection of distinct properties,
被視作是各種不同性質的集合體,
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for example, position,
例如:位置、
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momentum,
動量、
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and intrinsic spin.
還有自旋
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The values of these properties configure the particle,
這些性質的值共同決定粒子,
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giving it a quantum state identity.
給予它一個專屬量子態
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If two electrons have the same quantum state,
如果兩個電子有相同的量子態,
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they're identical.
他們就是相同的
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In a literal sense, our baseball is defined by a collective quantum state
口語一點來說,我們的棒球是由眾多原子的量子態
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resulting from its many atoms.
的集合所決定而成
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If this quantum state information could be read in Boston
如果這條量子態訊息可以在波士頓讀取
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and sent around the world,
再傳輸到全世界,
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atoms for the same chemical elements could have this information
訊息可以在邦加羅爾
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imprinted on them in Bangalore
標記在相同化學元素的原子上
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and be carefully directed to assemble,
再依照指示小心地組合,
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becoming the exact same baseball.
成為一模一樣的棒球
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There's a wrinkle though.
但有個困難點
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Quantum states aren't so easy to measure.
測量量子態可不簡單
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The uncertainty principle in quantum physics
量子物理中的測不準原理
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implies the position and momentum of a particle
指出一個粒子的位置和動量
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can't be measured at the same time.
無法同時測得
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The simplest way to measure the exact position of an electron
測量電子精確位置最簡單的方法
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requires scattering a particle of light, a photon, from it,
需要光粒子(光子)的散射,
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and collecting the light in a microscope.
並將光會聚在顯微鏡中
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But that scattering changes the momentum of the electron in an unpredictable way.
但是散射會隨機改變電子的動量
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We lose all previous information about momentum.
我們便失去之前所得知的、關於動量的所有資訊
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In a sense, quantum information is fragile.
也就是說,量子的資訊很脆弱
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Measuring the information changes it.
測量資訊的同時就改變了
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So how can we transmit something
那麼我們要如何傳送一個
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we're not permitted to fully read without destroying it?
我們無法完整讀取的東西而不破壞它?
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The answer can be found in the strange phenomena of quantum entanglement.
答案可以用量子糾纏的奇怪現象來解釋
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Entanglement is an old mystery from the early days of quantum physics
量子糾纏是量子物理早期的謎團
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and it's still not entirely understood.
且至今仍未被清楚地解釋
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Entangling the spin of two electrons results in an influence
兩電子自旋的糾纏會造成
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that transcends distance.
跨越距離的影響
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Measuring the spin of the first electron
測量第一個電子的自旋方向
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determines what spin will measure for the second,
便能得知第二個電子的自旋是什麼方向
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whether the two particles are a mile or a light year apart.
無論這兩個粒子距離多遠
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Somehow, information about the first electron's quantum state,
透過某種方法,第一個電子的量子態資訊,
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called a qubit of data,
又稱一量子位元的資訊,
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influences its partner without transmission across the intervening space.
能夠在不經過中間空間的情況下影響它的對應電子
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Einstein and his colleagues called this strange communcation
愛因斯坦和同事稱這種奇怪的傳訊方式為
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spooky action at a distance.
遠距離的鬼魅效應
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While it does seem that entanglement between two particles
雖然兩粒子間的糾纏現象看似
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helps transfer a qubit instantaneously across the space between them,
有助於橫越空間立即傳訊,
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there's a catch.
卻有個條件:
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This interaction must begin locally.
糾纏現象必須起於兩粒子在同一地點
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The two electrons must be entangled in close proximity
其中一個電子被傳送到別處之前
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before one of them is transported to a new site.
這兩個電子必須在極接近的距離糾纏
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By itself, quantum entanglement isn't teleportation.
若只有一個電子,量子糾纏便無法導致瞬間移動發生
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To complete the teleport,
要完成瞬間移動,
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we need a digital message to help interpret the qubit at the receiving end.
我們需要在接收端將量子位元轉換為數位訊息
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Two bits of data created by measuring the first particle.
測量第一個粒子會產生兩筆資訊
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These digital bits must be transmitted by a classical channel
這些數位資訊經由
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that's limited by the speed of light, radio, microwaves, or perhaps fiberoptics.
受光速限制的傳統途徑、無線電波、微波,又或許是光纖所傳送
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When we measure a particle for this digital message,
當我們測量到粒子的數位訊息,
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we destroy its quantum information,
我們也破壞了它的量子資訊
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which means the baseball must disappear from Boston
這表示棒球必須從波士頓消失
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for it to teleport to Bangalore.
才能瞬間移動到邦加羅爾
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Thanks to the uncertainty principle,
基於測不準原理,
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teleportation transfers the information about the baseball
瞬間移動將棒球的資訊在兩城市間傳輸
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between the two cities and never duplicates it.
而不會複製出另一顆球
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So in principle, we could teleport objects, even people,
所以理論上,我們可以瞬間移動物品,甚至人,
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but at present, it seems unlikely we can measure the quantum states
但是目前我們似乎不太可能測量出巨大物體之中
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of the trillion trillion or more atoms in large objects
上兆或更多原子的量子態
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and then recreate them elsewhere.
然後在別的地方重組它們
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The complexity of this task and the energy needed is astronomical.
這項任務的複雜度和所需能量大到無法想像
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For now, we can reliably teleport single electrons and atoms,
現在,我們可以確實地傳送各個電子和原子,
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which may lead to super-secured data encryption
這可能會使未來的量子電腦
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for future quantum computers.
有超安全資訊加密功能
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The philosophical implications of quantum teleportation are subtle.
將量子瞬間移動的哲學思考是很微妙的
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A teleported object doesn't exactly transport across space
瞬間移動的物體並非真的被運輸到別處
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like tangible matter,
像實體物質那樣,
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nor does it exactly transmit across space, like intangible information.
它也不算是像無形的資訊那樣傳輸
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It seems to do a little of both.
似乎兩種模式都有一點
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Quantum physics gives us a strange new vision
量子物理給我們一個奇特的新視角
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for all the matter in our universe as collections of fragile information.
將宇宙中所有物質視為脆弱資訊的集合
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And quantum teleportation reveals new ways to influence this fragility.
量子的瞬間移動揭示影響這種脆弱性質的新方法
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And remember, never say never.
記住,永遠別放棄
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In a little over a century,
在比一世紀長一點的時間內
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mankind has advanced from an uncertain new understanding
人類已經從剛摸索到電子
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of the behavior of electrons at the atomic scale
在原子層次的行為
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to reliably teleporting them across a room.
進步到可以確實讓他們瞬間移動到另一個空間
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What new technical mastery of such phenomena
這樣的現象
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might we have in 1,000, or even 10,000 years?
會在 1000 或甚至 10000 年後帶來什麼新的科技發展呢?
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Only time and space will tell.
只有時間和空間知道