轮回宇宙（Cyclocosmos）

一首含积分和导数的散文诗

将斯坦哈德和图洛克的轮回宇宙

联系起来

作者：比尔*罗宾森（Bill Robinson）

译者：郑 中（Geongs Zhern）

科学如自然那样影响着我们的心灵

不是特殊部分的精确性

也不是数量或函数这种优美的称谓

而是团队力量和全部结果

所以我在几行诗中要讲离奇故事

关于碰撞膜中的浩大宇宙学

拿起那张讲述全部轮回故事的图

我将以蜗牛的速度吟咏这首长诗

关于爆炸和膨胀的通常理解

现在必须处理一个严格偏差

加速膨胀和变化的哈波常数

回想解决麻烦的λ论文---

那是爱因斯坦的成就；而哲学家的微妙

情况引起许多争议

无厘头弄出个新的标量势

幂指数增长，但为何、何时、何去、因此

的本意是什么？

它为何发生？大爆炸之前

发生了什么？而精细常数

如此多，如此重要；我们抛弃假设

我们的小泡泡恰好合适

宇宙其余部分，现在丢失于夜空

超出我们视界（即膨胀）是无边界的

这恰恰就是狭义的，虽然之前是无根据的

为了理解自身居于宇宙秩序中

一种在特别场所熟悉的名称

事物在丹麦腐烂

而不只是哈姆雷特会作评论

现面对这种神秘性，我们可做什么呢？

或许也听听一点哥白尼的历史训示

一把奥克母锋利的剃刀

割掉传统---不作思想的奴隶

我们居于一张邻近的膜上

穿过无可飞越的第五维

当它们被费曼分开，标量势

支配着膨胀并偶然收缩

它加速爆炸，并产生新物质

使一切变得比早期理论

所预测的曲率更平缓

我们的宇宙就是这个系列之一

不断复发，呈无限序列

熵在递增，看似稀释

无人可解，而万物不停息

爱因斯坦的幽灵皱眉尖叫

“GR给出什么？你用β、φ点和人为的标量因子

制造了一个灾难，我可爱的传统钟现在走着共形时间---

理论听起来就像牵强的韵诗！”

噢亲爱的！毕竟爱因斯坦博士强加的宇宙协调

是严肃的事业，变动能经受检验吗？

没直接的方法，但LISA最好

在稳定与界膜之间折衷

爆炸产生的引力余波正在传播

古斯的膨胀论是正确的；如果不是

那么轮回是满意的，而斯坦哈德胜利了

在爆炸后的一秒，产生新的

解决了宇宙的重复问题

这是天堂的理论，而不是地狱的

与数据比较，理论看来正确---

星系在欧几里德空间中加速飞行

无限大具有光滑微波

那些来自爆炸的各向同性光子

就是导致膨胀的第一位原因

如果朝空间反方向看去

为何都相似？它们不曾通信！

不管星系如何快行，A与B不接触

膨胀快速平滑，然后消逝弥散

宇宙轮回以百亿年为期

然后大塌缩，现在这些区域超距通信

超出其视界，而变得符合

与演化到每个星系的碰撞谱

于是星系团和虚空皆可见

让我们游览从现在到现在的全部轮回

解释每一个步，然后显示

它如何取决于势V和标量场φ

跳过如此复杂的数学，乃至使学者攘攘

为了大胆阅读，一目千篇

我们抓住精髓，约定规范

需要图像而不是语言

V作为动能的横轴

而φ作为势能的纵轴

沿这条奇怪的曲线，从极小到当前

将达到我们曾经的时代

膨胀变得更快；不久滚下坡来

V和φ潜过零点下，膨胀减慢

直到亿万年才停止---我们即将坍缩

共形时间变为负，于是才有正常图景

仅当千亿年后，我们位于第四点

在大挤压后的一秒，万物向前

更快速地演化；然后我们神经绷紧

让我不要碰到两张膜

那是障碍。V回到其最小值

然后返回连续统的死亡零点---

或者看起来φ无穷大

标量因子变为零。只有神

或者β，可从类点终结中挽救我们

但a帽是有限的，而当膜分离时

我们通过新物质洪流的曲面

而φ返回为点，并开始新天

在一介秒后，我们返回第八个点

φ扳动天机，宇宙沉静

在第140多亿年后，变成我们宜居的状态

一个并非最优的位置和时代

斯坦哈德和图洛克的轮回理念

本来就是手段，并非固定不变

因为万有理论有其道理

它指出超越时空的存在

人类的正确研究是物理

如果它超出轮回的极限

这种循环的宇宙就完全机械

可与实验相比，但不真实

教皇、伏尔泰和斯威夫特的训导，

给我们一个死亡的世界，并拒绝

高于岩石、泥土的礼物

当我们坐下祈祷，难道一无所得？

然而，这些轮回没有描写

人类的意识，传道士说它存在

这样结束这首长诗，希望你不要厌倦

或迷惑不解，但我不在乎你打鼻鼾

客体无穷尽，超越心灵极限

我们敢否窥探？那将有什么发现？

感性和逻辑的世界撒了谎言

但这就是我们的所有，所以物理学家在试干！

译注：这首诗于2004年5月发表于Astrophysics（PY 543），于美国北卡罗来纳州立大学（NCSU）。此诗原文还算押韵，但译成汉语后，很难保持韵脚了；此诗杂许多抽象的物理术语，缺乏修辞，诗句不够精短，使一般人读起来似乎枯燥无味（必须结合那张曲线图读之）。但讲的是无奇点大爆炸的膜碰撞轮回宇宙模式，值得一读。

英文原文：

In Science, as Nature, what affects our hearts

Is not the exactness of peculiar parts;

`Tis not a number, or function, we beauty call,

But the joint force and full result of all.

So I’ll tell the quaint tale in several quatrains

Of  a vast Cosmology in Dueling Membranes.

Behold Figure One telling the whole Cycle’s Tale

While I chant this long Poem at the pace of a Snail.

The common wisdom of Bang and Inflation

Must now deal with a serious Aberration

Of accelerated Expansion and an Inconstant Hubble.

Reviving Lambda papers over the trouble—

For Einstein, Triumph; but for Philosophers subtle,

The scenarios offered cause many to grumble.

Plucked out of nowhere, this new Scalar Potential

Powers the growth, but what is essential

Is a sense of Why? When? Whither? Wherefore?

Why does it happen? What happened before

The Big Bang? And the Numbers fine-tuned,

So many, so Vital; we’re left to assume

Our little Bubble had it precisely all right.

The rest of the Cosmos, now lost in the Night

Beyond our Horizon (says Inflation) is boundless.

Right here is Special, though before it was groundless

To see ourselves Central in the Universal Order.

A privileged Place has a familiar Odor.

Something is rotten in the State of Denmark,

And not only Hamlet can make that remark.

Now what can we do when faced with this Mystery?

Perhaps we do well with lessons from History.

A touch of Copernicus, one of Occam’s close shaves,

Abandoning convention—to no Idea be Slaves.

For Steinhardt and Turok, well-versed in M Theory

(Which to most is Obtuse and makes our heads weary)

Four-D is no limit; the Five of Kaluza-Klein

Gives space for two Branes and a Solution sublime.

We live on one Brane with another nearby

Across that Fifth Dee o’r which nothing can fly.

While they’re separate by Fermis, the Scalar Potential

Governs expansion and contraction in ways Providential.

It powers the Bang and gives rise to new Matter

And makes it all happen with Curvature flatter

Than could have been possible with earlier Theories.

It means that our own Universe is just one of a Series,

Born again and again in infinite Sequence

With increasing Entropy so dilute in appearance

That no one can see it and Nothing runs down.

The Specter of Einstein comes neigh with a frown;

“What gives with GR? You’ve made a Disaster

With Beta and Phi-dot and a custom Scale Factor.

My dear Proper Clock is now Conformal Time—

Sounds like a theory contrived for the Rhyme!”

Oh dear! After all, to be charged with a crime

Of Cosmic proportions by Doctor Einstein

Is serious business. Can the Variation stand test?

There’s no direct way, but LISA is best

For choosing ‘tween ‘flation and Branes that are bouncing.

Left-over G-waves from the Bang are announcing

Guth’s Inflation is right; while if there are none,

Then Cycles have favor and Steinhardt has won.

Recurring Big Bangs with no Singularities—

As wholesome as Shakespeare without the Vulgarities.

How do they manage? It’s a little complex;

Metric dt squared is a-hat squared dx

Squared minus dt squared. It’s a-hat that matters,

Staying finite while Everything crunches to tatters—

Clear down to Quark Soup, but not down all the way  

Like Robertson-Walker’s scale factor a.

(Don’t grow to Infinity and don’t shrink to Zero;

If your theory does this than you’ll be a Hero.)

Why are things this way, and not something Other?

The cyclical Pattern is like an Attractor,

So that once it gets going it starts to converge

And all possible Variants in time nearly merge.

Not quite exactly, it’s not just repeating—

Post-Bang in a second it’s different, defeating

The problem of re-runs we all know too well;

This theory’s of the Heavens and not one of Hell.

Compared to the data, the theory seems right—

Euclidean, with Galaxies accelerating in flight,

Infinitely large with smooth Microwave.

Those isotropic photons from the Bang is what gave

The reason for making Inflation in the first place.

If you look in directions opposite in Space,

Why are they similar? They haven’t been talking!

No A to B contact, no matter how fast they’re walking.

Inflation smoothes quickly and then disappears

Into Nowhere. But Cycles use a billion Years

Before the Crunch, so Regions now distant commune

Beyond their Horizons and become in tune

With the Spectrum of bumps that evolve to each Galaxy

And Cluster and Void that all can now see.

Let’s tour the whole Cycle from Now to Now

Explaining each step, and then showing how

It depends on Potential V and Scalar Field Phi,

Skipping Math so complex that grown Scholars cry.

We contemplate the Gist, and communicate that Deed,

For Fools rush in where Angels fear to read.

With a ratio of one to a thousand, you’ll agree

We need Pictures, not Words: see Figure Three.

With V as abscissa and Phi as the ordinate,

Energy both Kinetic and Potential coordinate

Along this strange curve from minus forever to One

Where we are now, as we’ll be when we’re done.

Our expansion grows quicker; soon we roll downhill.

V and Phi flow below zero, Expansion slows until

In Trillions of years it ceases—we’re due for Collapse.

Conformal Time flips negative, so Normality snaps.

In only Ten Billion we’re at Point number Four,

A second from Crunch. Everything onwards is more

Quickly evolving; to follow, our Minds suffer Strains.

Let me not to the meeting of two Branes

Admit impediment. V goes past its Minimum

And then back to Zero at the Death of the Continuum—

Or so it would seem when Phi is minus Infinity.

Scale factor a declines to Nothing. Only Divinity,

Or Beta, can save us from a point-like End.

But a-hat is Finite, and we pass through the Bend

With a flood of new Matter as the Branes pull apart

And Phi’s back to Zero, giving all a fresh Start.

In a Zeptosecond we return to Point Eight;

Phi puts on the Brakes and becomes quite Sedate.

Fourteen Billion Years more marks our inhabited State,

An Unpreferred Place and Unpreferred Date.

The Cyclic Idea of Steinhardt and Turok in

Essence is Method, not settled and locked in

As Theory with everything set in its place.

It points to existence beyond Time and Space.

The proper study of Mankind is Physics,  

If it be extended beyond the limits of Cynics.

This cyclical Cosmos is all mechanistic

Which compared to Experience, is not Realistic.

The Enlightenment of Pope, Voltaire and Swift

Gives us a dead World and throws out the Gift

Of something transcendent to Rock, Mud, and Clay.

Is there nothing that happens when we sit down to pray?

However advanced, these Cycles don’t feature

Our Awareness, which exists—sayeth the Preacher.

So ends this long Poem with hopes you aren’t bored

Or bewildered, and I forgive if you’ve snored.

The subject is Endless, beyond limits of Mind;

Shall we venture to look? And What shall we Find?

The World of the Senses and Logic tells Lies,

But it’s what we have here, so a Physicist—tries!

Composed May 5-8, 2004 for presentation in Astrophysics (PY 543)

At NCSU

References:  

Alexander Pope, An Essay on Criticism (1711)  

A. Pope, Essay on Man, Epistle II (1733-1744)  

W. Shakespeare, The Tragedy of Hamlet, Prince of Denmark (1604)  

W. Shakespeare, Sonnet CXVI  

Paul Steinhardt, Neil Turok, Cosmic Evolution in a Cyclic Universe, arXiv:hep-th/011098 v2  (20 Mar 2002)  

P. Steinhardt, N. Turok, Science, 296, 1436 (24 May 2002) “A Cyclic Model of the Universe”  

P. Steinhardt, N. Turok, Designing Cyclic Universe Models, arXiv:hepth/0307132 v4  (18 Jan 2004)

Figure 1 (Discover Magazine, February 2004)

Figure Two:  

Mathematical Ingredients Boiled down to a Minimum to Help Follow the Poem

The universe is flat and homogeneous

with a being the Robertson-Walker scale factor.  

The effects of β include a fifth force that violates the equivalence principle, too weakly to observe now. One possible function for β(φ):

For the transition to allow a smooth passage, a above is replaced with scale factor . This new, improved scale factor stays finite as  a → 0 at the transition. This means that on the branes,  

One of two equations of motion is

    Thus V represents what is customarily thought of as dark energy density, which acts like negative pressure.  

Proper time is rarely used in the cyclic universe literature. Instead, the two main forms of time are coordinate time t as used above, and conformal time τ; . Since it uses , τ flows through the bounce when a → 0.