experiments at the Large Hadron Collider

在大型強子對撞機(LHC)的實驗裡

discovered the Higgs boson.

希格斯玻色子被發現了

It was a historical day.

那是歷史性的一刻

There's no doubt that from now on,

無庸置疑地,從現在開始

the Fourth of July will be remembered

7月4號不再被認為是 美國獨立紀念日

not as the day of the Declaration of Independence,

而是發現希格斯玻色子的重要日子

but as the day of the discovery of the Higgs boson.

至少對歐洲核子研究組織是這樣的

Well, at least, here at CERN.

但是對我而言,那天最大的驚喜

But for me, the biggest surprise of that day

就是沒有太大的驚喜

was that there was no big surprise.

在物理理論學家的眼中

In the eye of a theoretical physicist,

希格斯玻子是一個很絕妙的解釋

the Higgs boson is a clever explanation

它解釋了一些基本粒子如何獲得質量

of how some elementary particles gain mass,

但是這看來就是個不盡滿意

but it seems a fairly unsatisfactory

而且不夠完整的解答

and incomplete solution.

太多問題都無法回答

Too many questions are left unanswered.

希格斯玻色子不夠美麗

The Higgs boson does not share the beauty,

不夠均稱,不夠優雅

the symmetry, the elegance,

不足以和基本粒子世界相比

of the rest of the elementary particle world.

因此,大多數理論學家

For this reason, the majority of theoretical physicists

不相信希格斯玻色子就是所有的真相

believe that the Higgs boson could not

我們希望新的粒子和新的現象

be the full story.

能隨著希格斯玻色子出現

We were expecting new particles and new phenomena

但目前從LHC對撞機得來的測量 卻沒有顯示什麼新的粒子和新的現象

accompanying the Higgs boson.

當然,目前的論斷並不是絕對的

Instead, so far, the measurements

2015年,LHC對撞機將會加倍

coming from the LHC show no signs of new particles

質子撞擊的能量

or unexpected phenomena.

這些更強烈的撞擊

Of course, the verdict is not definitive.

能讓我們進一步了探索粒子世界

In 2015, the LHC will almost double

我們一定能從中知道更多

the energy of the colliding protons,

但當下我們還沒找到新現象的證據

and these more powerful collisions

讓我們假設我們今天知道的粒子

will allow us to explore further the particle world,

包含希格斯玻色子

and we will certainly learn much more.

是自然界中僅有的基本粒子

But for the moment, since we have found

即使它們能爆發的能量 比我們今天所知的多上更多

no evidence for new phenomena, let us suppose

我們來看看這個假設會帶來什麼事

that the particles that we know today,

我們會發現宇宙驚奇又迷人的結果

including the Higgs boson,

在我繼續解釋之前

are the only elementary particles in nature,

先讓我說明希格斯玻色子是什麼

even at energies much larger

要說明的話,我們必須回到

than what we have explored so far.

宇宙大爆炸之後的百億分之一秒

Let's see where this hypothesis is going to lead us.

根據希格斯理論

We will find a surprising and intriguing result

在那瞬間 一件非常戲劇化的事件在宇宙中發生

about our universe, and to explain my point,

時空經歷轉變期

let me first tell you what the Higgs is about,

這個轉變期 和水在零度以下結冰的過程非常像

and to do so, we have to go back

但這個例子裡

to one tenth of a billionth of a second

轉變期不是分子在物質裡的重新排列

after the Big Bang.

而是時空結構的改變

And according to the Higgs theory,

在這段轉變期,空間充滿物質

at that instant, a dramatic event took place

就是我們說的希格斯場

in the universe.

這種物質我們可能看不見

Space-time underwent a phase transition.

但卻擁有物理性質

It was something very similar to the phase transition

它隨時環繞我們

that occurs when water turns into ice

就像我們在這房間內呼吸的空氣一樣

below zero degrees.

有些基本粒子和這種物質互動 從過程中獲得能量

But in our case, the phase transition

這種內在的能量 就是我們今天說的粒子質量

is not a change in the way the molecules

而藉由發現希格斯玻色子

are arranged inside the material,

LHC對撞機證實這種物質是真的

but is about a change

因為希格斯玻色子正由這種物質組成

of the very fabric of space-time.

簡單來說,這就是希格斯故事的梗概

During this phase transition, empty space

但更有趣的在後頭

became filled with a substance

研究希格斯理論的同時

that we now call Higgs field.

理論學家發現

And this substance may seem invisible to us,

並非經由實驗,而只是數學演算

but it has a physical reality.

他們發現希格斯場並不是 只以我們今日發現的形式存在

It surrounds us all the time,

就像物質可以有液態和固態兩種狀態

just like the air we breathe in this room.

所以希格斯場 也就是那填滿時空的物質

And some elementary particles interact

可以存在於兩種狀態下

with this substance, gaining energy in the process.

除了已知的希格斯場之外

And this intrinsic energy is what we call

希格斯場還可能比現在 所知的高出幾十億密度存在

the mass of a particle,

光是另一種希格斯場的可能存在

and by discovering the Higgs boson, the LHC

就帶來了潛在的問題

has conclusively proved that this substance is real,

因為根據量子力學定律

because it is the stuff the Higgs bosons are made of.

兩種狀態之間的轉變是有可能的

And this, in a nutshell, is the essence of the Higgs story.

即使兩個狀態之間有能量差間隔

But this story is far more interesting than that.

詞如其名,這個現象被稱為量子穿隧

By studying the Higgs theory,

因為量子穿隧效應

theoretical physicists discovered,

我可以從這間房間消失

not through an experiment

再從另外一個房間出現

but with the power of mathematics,

簡單來說就是穿越牆壁

that the Higgs field does not necessarily exist

但別期待我會真的在你們面前表演

only in the form that we observe today.

因為讓我能穿越牆壁的機率十分渺小

Just like matter can exist as liquid or solid,

在這發生之前你們得等上好一陣子

so the Higgs field, the substance that fills all space-time,

但相信我 量子穿隧是一個真實存在的現象

could exist in two states.

且已經被很多機制發現

Besides the known Higgs state,

例如,穿隧兩極真空管 一個在電子學中常用的組件

there could be a second state in which the Higgs field

因為量子穿隧效應而被製造出來

is billions and billions times denser

但讓我們再回到希格斯場

than what we observe today,

如果超濃度的希格斯場存在

and the mere existence of another state

那,因為量子穿隧效應

of the Higgs field poses a potential problem.

在這狀態下的泡泡 可以突然出現在宇宙中的特定時空

This is because, according to the laws

就和我們煮滾水的時候一樣

of quantum mechanics, it is possible

蒸氣泡泡從水中蒸發

to have transitions between two states,

然後膨脹,從液態變成氣態

even in the presence of an energy barrier

同理,一顆泡泡在超濃度的希格斯場

separating the two states,

可以因為量子穿隧效應而出現

and the phenomenon is called,

泡泡會以光速膨脹,佔領空間

quite appropriately, quantum tunneling.

將希格斯場從熟悉帶到全新的狀態

Because of quantum tunneling,

這是個問題嗎?

I could disappear from this room

是,很大的問題

and reappear in the next room,

在日常生活中可能難以理解

practically penetrating the wall.

但希格斯場的密度 對於物質構造非常重要

But don't expect me to actually perform the trick

如果希格斯場密度只是比一般高一點

in front of your eyes, because the probability

我們就會看到原子核中原子收縮

for me to penetrate the wall is ridiculously small.

中子衰變,核子解體

You would have to wait a really long time

氫會變成宇宙中 唯一可能存在的化學元素

before it happens, but believe me,

而超濃度的希格斯場

quantum tunneling is a real phenomenon,

並不是只比今天的希格斯場 密度高上幾倍

and it has been observed in many systems.

而是幾十億倍

For instance, the tunnel diode,

如果時空被這個希格斯場填滿

a component used in electronics,

所有原子物質都會崩解

works thanks to the wonders

沒有任何分子結構能夠存在 沒有生命

of quantum tunneling.

所以我想

But let's go back to the Higgs field.

未來希格斯場有可能會經歷轉變期

If the ultra-dense Higgs state existed,

和量子穿隧效應

then, because of quantum tunneling,

進入這個恐怖,高濃度的狀態嗎?

a bubble of this state could suddenly appear

換句話說,我問自己

in a certain place of the universe at a certain time,

希格斯場在宇宙中的命運是什麼?

and it is analogous to what happens when you boil water.

而回答這個問題的關鍵 在於希格斯玻色子的質量

Bubbles of vapor form inside the water,

在一次LHC的實驗裡發現

then they expand, turning liquid into gas.

希格斯玻色子的質量 是1260億電子伏特

In the same way, a bubble of the ultra-dense Higgs state

用我們熟悉的單位表示的話其實不多

could come into existence because of quantum tunneling.

差不多是10的負22次方公克

The bubble would then expand at the speed of light,

但是對粒子單位來說很大

invading all space, and turning the Higgs field

它就等於是整個DNA分子的重量

from the familiar state into a new state.

有了從LHC得到的資料

Is this a problem? Yes, it's a big a problem.

再加上從歐洲核子研究組織得到的

We may not realize it in ordinary life,

我們試著計算

but the intensity of the Higgs field is critical

宇宙經過量子穿隧 進入高濃度希格斯場的可能性

for the structure of matter.

結果非常有趣

If the Higgs field were only a few times more intense,

我們的計算顯示

we would see atoms shrinking, neutrons decaying

希格斯玻色子的質量非常特別

inside atomic nuclei, nuclei disintegrating,

它的質量剛剛好

and hydrogen would be

可以讓宇宙處在一個不安定的狀態

the only possible chemical element in the universe.

希格斯場的結構至今為止 仍處於搖擺不定的狀態

And the Higgs field, in the ultra-dense Higgs state,

但最終還是會崩塌

is not just a few times more intense than today,

根據我們的計算

but billions of times,

我們就像露營的人

and if space-time were filled by this Higgs state,

不小心將帳篷搭在懸崖邊

all atomic matter would collapse.

最後,希格斯場會經歷轉變期

No molecular structures would be possible, no life.

然後所有的物質會自我毀滅

So, I wonder, is it possible

所以人類文明就是這樣消失的嗎?

that in the future, the Higgs field

我不這樣覺得

will undergo a phase transition and,

我們的計算顯示

through quantum tunneling, will be transformed

希格斯場的量子穿隧

into this nasty, ultra-dense state?

在接下來的10年到100年 不太可能會發生

In other words, I ask myself, what is the fate

這是一段很長的時間

of the Higgs field in our universe?

甚至比義大利成立穩定的政府還要長

And the crucial ingredient necessary

即使發生了,我們也已經不在了

to answer this question is the Higgs boson mass.

在約50億年後

And experiments at the LHC found that the mass

太陽會變成紅巨星

of the Higgs boson is about 126 GeV.

和地球繞日的軌跡一樣大

This is tiny when expressed in familiar units,

地球會毀掉

because it's equal to something like

1兆年之後

10 to the minus 22 grams,

如果黑暗能量還在供給

but it is large in particle physics units,

太空依現在的速度膨脹

because it is equal to the weight

你連到腳趾頭這麼短的距離都看不到

of an entire molecule

因為你身邊的事物

of a DNA constituent.

都在以比光速還要快的速度膨脹

So armed with this information from the LHC,

所以要我們看到希格斯場膨脹 真的不怎麼可能

together with some colleagues here at CERN,

我對希格斯場轉換感興趣的原因是

we computed the probability

因為我想問:

that our universe could quantum tunnel

為何希格斯玻色子的質量如此特別?

into the ultra-dense Higgs state,

為何它剛剛好讓宇宙

and we found a very intriguing result.

處於轉變的邊緣?

Our calculations showed

理論學家永遠喜歡問"為什麼"

that the measured value of the Higgs boson mass

不只是想要知道現象的成因

is very special.

理論學家更感興趣的是

It has just the right value

為何一個現象會以現在這個方式運作

to keep the universe hanging

我們覺得這些"為什麼"可以給我們線索

in an unstable situation.

找尋自然的基本定律

The Higgs field is in a wobbly configuration

而能解答我問題的可能答案

that has lasted so far

開啟了整個宇宙 真的是字面上的開啟

but that will eventually collapse.

一直有人懷疑

So according to these calculations,

我們的宇宙只是 眾多宇宙泡沫堆中的一個泡泡

we are like campers

眾多宇宙裡有數以萬計的泡泡

who accidentally set their tent

每個泡泡都是一個不同的宇宙

at the edge of a cliff.

擁有不同的內容物

And eventually, the Higgs field

還有不同的定律

will undergo a phase transition

在這個假設下

and matter will collapse into itself.

我們只能討論確定希格斯質量的可能性

So is this how humanity is going to disappear?

那麼解開謎團的關鍵

I don't think so.

就在這眾多宇宙中的統計特性

Our calculation shows that quantum tunneling

它可能類似沙灘上的沙丘

of the Higgs field is not likely to occur

基本上你可以想像 在沙灘上的任何坡度找到沙丘

in the next 10 to the 100 years,

但是沙丘的坡度通常都在30到35度左右

and this is a very long time.

原因很簡單

It's even longer than

因為風堆起沙子,重力讓沙子掉下來

the time it takes for Italy to form a stable government.

所以大部分的沙丘

(Laughter)

都擁有剛好接近崩塌的斜度

Even so, we will be long gone by then.

類似的事情也可能 發生於眾多宇宙中的希格斯玻色子

In about five billion years,

在眾多宇宙的泡泡中

our sun will become a red giant,

希格斯的質量 可能也在希格斯場接近崩塌的邊緣

as large as the Earth's orbit,

就像在沙丘的例子裡 有兩個互相抗衡的效應一樣

and our Earth will be kaput,

我的故事不會結束

and in a thousand billion years,

因為我們還不知道故事的結局

if dark energy keeps on fueling

科學一直在前進

space expansion at the present rate,

為了解開謎團,我們需要更多數據

you will not even be able to see as far as your toes,

希望LHC不久後 又會為這個故事提供更多新線索

because everything around you

光是發現希格斯玻色子的質量

expands at a rate faster than the speed of light.

就讓我們知道這麼多

So it is really unlikely

我一開始假設 已知的粒子都在宇宙之中

that we will be around to see the Higgs field collapse.

甚至超出我們所知的宇宙

But the reason why I am interested

從這我們發現能跨越時空的希格斯場

in the transition of the Higgs field

可能處在刀鋒 隨時可能引起宇宙崩塌

is because I want to address the question,

我們發現這可能提醒我們

why is the Higgs boson mass so special?

我們的宇宙 只是眾多宇宙沙灘中的一顆沙粒

Why is it just right to keep the universe

但我並不知道我的假設正不正確

at the edge of a phase transition?

這就是物理學的運作方式

Theoretical physicists always ask "why" questions.

一套測量可將我們推向認識宇宙的新路

More than how a phenomenon works,

也可以送我們進死胡同

theoretical physicists are always interested in

但不論結果如何

why a phenomenon works in the way it works.

有一件事我很確定:

We think that this these "why" questions

這趟旅程將會充滿驚喜

can give us clues

謝謝

about the fundamental principles of nature.

And indeed, a possible answer to my question

opens up new universes, literally.

It has been speculated that our universe

is only a bubble in a soapy multiverse

made out of a multitude of bubbles,

and each bubble is a different universe

with different fundamental constants

and different physical laws.

And in this context, you can only talk about

the probability of finding a certain value of the Higgs mass.

Then the key to the mystery

could lie in the statistical properties

of the multiverse.

It would be something like what happens

with sand dunes on a beach.

In principle, you could imagine to find sand dunes

of any slope angle in a beach,

and yet, the slope angles of sand dunes

are typically around 30, 35 degrees.

And the reason is simple:

because wind builds up the sand, gravity makes it fall.

As a result, the vast majority of sand dunes

have slope angles around the critical value,

near to collapse.

And something similar could happen

for the Higgs boson mass in the multiverse.

In the majority of bubble universes,

the Higgs mass could be around the critical value,

near to a cosmic collapse of the Higgs field,