百科知識視頻之煎蛋小學堂40 平行世界與多重世界

One of the biggest secrets of physics is that we still don't fundamentally understand what happens when the smallest things interact with big things,that is when quantum mechanics meets our everyday world.

物理學的最大秘密之一便是，我們仍然沒有從根本上理解 當極小的物體和大物體相互作用時會發(fā)生什么 也就是說，當量子力學和我們的日常生活相遇時，會發(fā)生什么。

You've probably heard of the "Schrodinger's Cat"experiment where a particle (in this case a cat)is in a superposition of two states (both dead and alive)at once,until it interacts with the outside world,normally a photon of light that we send in to see what's going on (but it could also just be a random particle that has nothing to do with us).Upon interaction with the outside world,the cat is observed as being either dead,or alive,but not both.

你也許聽說過“薛定諤的貓”的實驗。一個粒子(在這個實驗中是一只貓) 同時處于兩種狀態(tài)的疊加(即死又活)中，直到它 與外界相互作用，通常是我們?yōu)榱颂角鍍炔壳闆r發(fā)送的一束光子 有可能是一個與我們沒有任何關系的隨機粒子。在與外界 相互作用之后，人們認為這只貓或活或死，但非即死又活的狀態(tài) .

The problem is,physics can't explain how the cat,or particle,goes from being in a combination of two states at once to being in "just one",or "just the other";nor do we know how the "decision"is made.This isn't just a problem with cats,either,It plagues every single quantum mechanics experiment,famous or otherwise,from the double slit experiment and quantum teleportation to the Stern-Gerlach experiment and tests of the Bell inequalities.In every case,we can predict how likely it is for a particle to be in one state or another,but have no clue how it actually ends up that way,That's where the many-worlds picture of quantum mechanics comes in-basically,"many-worlds"proposes the idea that the quantum system doesn't actually decide-rather,at every junction where large everyday stuff interacts with a quantum system,the timeline of history splits and both possibilites happen on different,alternate branches,You know,a choose-your-own-adventure where every possible story happens.

問題是，物理學不能解釋貓，或者粒子是如何 怎么從兩種狀態(tài)的疊加一下子變?yōu)?一種狀態(tài)，或另一種，我們亦無從得知這樣的“決定”是怎么做出的 這也不只是貓的問題，它困擾著每一個量子力學實驗 無論實驗是否知名，從雙縫，干涉實驗，量子隱形傳送實驗 到斯特恩-蓋拉赫實驗，貝爾不等式的檢驗。在每一種情況下，我們 都能預測粒子在不同狀態(tài)下的可能性，但無法知道 它實際上是怎么達到這個狀態(tài)的。量子力學的多重世界的圖景就是這么 被引入的。基本上說，“多重世界”推崇的是量子系統 并不做出最終的“決定”，相反，在每個交匯處 當生活中常見的大物體和量子系統相互作用時，歷史的時間軸 分成兩半，事物的兩種可能性發(fā)生于 兩個不同的，相互間隔的分支。就是在一個什么都有可能 發(fā)生的故事里選擇自己的命運。

In this scenario,we'd think that only one possibility happened because we'd be stuck on one of the branches,in a version of ourselves that only sees one possibility happen.In some ways,this sounds pretty fishy,I mean,it's hard to test the reality of a universe that hides its true nature from us by not allowing us to test or observe its true nature.But anyway,in the many-worlds picture of quantum mechanics,"branch-points"are predicted to happen all the time,everywhere.Pretty much any time subatomic particles interact with each other,or with anything else,anywhere in the universe,there are multiple possible outcomes.Which means a LOT of branching of history.There may even be infinitely many branches.

在這種情況下，我們 認為只有一種情況發(fā)生了，因為 我們最終停在了一個分支上，也就是說我們僅僅看到一種可能性 成為現實。這似乎聽上去有些不對勁。我的意思是，想要考證 一個不容我們考證或者觀察其本質的宇宙的真實面貌 的確很難。但不論如何，在量子力學的多重世界圖景中，“分支點”一直在產生，無論任何時間或任何地點。正如 亞原子粒子在宇宙中任何地點與任何一個亞原子或者其他物質 相互作用時，會產生多種可能的結果。這對于歷史“分支”來說 意義重大。這種分支的數量可能有無窮多。

So is the Many Worlds hypothesis true?We don't know -it hasn't yet been tested experimentally.There's a bit of mathematics that supports it,and there are also a number of mathematical models that don't require such an extravagantly big & complex picture of the universe,But luckily,physics is science,not speculation,and eventually,someone,maybe even you,will perform an experiment that helps us discover the truth.

所以“多重世界”假說是真的么 我們并不知道尚無實驗對其作出證明。有很多數學公式支持它存在。同時，也有許多數學模型 并不支持如此揮霍無度而又復雜的 宇宙圖景。幸運的是，物理是一門科學而非投機活動，最終 會有人，甚至可能是你能夠設計出一個實驗來幫助我們 探索出真相。