How the world has changed in half an hour

Breakthrough to the edge of the world

After a month and a half, the electronic one will be released, and after more than two - Boris Stern’s paper book called “Breakthrough beyond the World”. Its scientific editor is Academician of the Russian Academy of Sciences Valery Rubakov , technical and any other editor - Maxim Borisov , interlocutors: Andrey Linde, Vladimir Lukash, Vyacheslav Mukhanov, Valery Rubakov, Alexey Starobinsky . The last five are known to any earthling interested in modern cosmology. Some of them are real applicants for the Nobel Prize for the theory of cosmological inflation, which, according to the firm conviction of the author of the book, will be awarded during the life of the current generation of readers.

The book is devoted to science in general on the example of modern cosmology and, most importantly, the theory of cosmological inflation underlying it. In addition, a story is being conducted about how the universe would be investigated, physically limited in their capabilities, but not inferior to us in mind. As an example, the inhabitants of the Upiter of Jupiter Europe are taken as an example. Hence the subtitles of the book "On Cosmology of Earthlings and European."

How the world has changed in half an hour

The text below can be called a story rather than an interview. The author was prepared for questions, but Andrei regularly anticipated them - it only remained to listen and remember.

Boris Stern: Let's start with the story. When it became clear to you that the theory of inflation is the most important answer to the main issues of cosmology?

Andrei Linde : Perhaps it was stretched in time, it is better to state the chain of events. We walked around the Bu around 1976, when with David Abramovich Kirzhnitsa we were engaged in a phase transition in electriclaboration of interaction. We saw that the Universe can get stuck in a hypothermia, when a field of the Higgs field is dominated by the energy density of everything, and get stuck for a long time. This is just what later became the basis for the first inflationary models, but then we had completely different tasks - we did not think at all in this direction.

We soon thought about how to get the right entropy from this, how to explain the bario asymmetry with hypothermia (we recall that the baronic asymmetry requires a violation of thermal balance, which gives a phase transition with hypothermia. - B.Sh. ) on this topic we had work with the genus of Chibisov in 1978 - we also collided there bubbles of new Phases, as in the script of Alan Guth. But we did not have the idea to see how the phase transition affects the dynamics of the universe - we were interested in the birth of the barions.

The first self -compiled description of how the world of de Sitter could arise in 1980 in the work of Alexei Starobinsky. It was a brilliant work, in Russia it was lively discussed at seminars and conferences. I remember Andrei Sakharov was in a state of joyful excitement about Alexei's work. But there was one circumstance that puzzled me. The early Universe, described in his model by the decision of de Sitter, was not a singular - its story could be unlimitedly continued in time, bypassing the state of endless density. But the world of de Sitter at the same time turned out to be unstable, and this instability made such an assumption impossible. In addition, Alexei wrote the following in his work: "Our script is exactly the opposite of the Mizner's original chaos." This contradicted the basic idea of ​​inflationary cosmology: you need to describe how the universe has become so “good”, starting with anything. This is in the script of Guta, and in all subsequent ones. And for Alexei, on the contrary, the universe begins with a “good” pure state, from the world of de Sitter, and then all sorts of perturbations occur with it.

But these problems were fixed. Soon, Zeldovich's visionary work came out, where he offers to interpret the model of Starobinsky as a scenario of the birth of the Universe from nothing. Then this was formalized by Sasha Vilenkin. Then, in 1983, after my article on chaotic inflation, Alexei modified his model on a similar basis, and his model became part of a more standard approach to inflationary cosmology.

Despite the doubts that existed at that time, the glory of Mukhanov and Gene Chibisov decided to push all these problems aside, take the Starobinsky model and see how they would behave in it of the quantum fluctuations of the metrics - what spectrum of disturbances they will give. Previously, the most popular hypothesis was the flat spectrum of Harrison - Zeldovich, but it was taken from the ceiling, simply to explain the data on the large -scale structure of the universe. Mukhanov and Chibisov found that this spectrum was obtained from the Starobinsky model in the first approximation. They also calculated the deviation from the flat spectrum - it is actually logarithmic, and now it is precisely what is evident according to WMAP and the “bar”.

From the work of Mukhanov and Chibisov it followed that the galaxies and their accumulations nothing more than former quantum disturbances, first stretched by inflation, and then intensified due to gravitational instability. At first, such a statement caused mass rejection: how can a huge classic object appear as a result of quantum processes?! Now this is a common place.

At that time, many began to wonder how to get a large homogeneous universe, but everyone faced some problems. I got to the Rubakov seminar - they tried to explain why the universe is large and flat, based on the model of Kolman - Weinberg. But nothing came of it. When Lev Borisovich Okun called me and said Guta, I immediately explained why this would not work, we already dealt with the breakdown of a hypothermia of the scalar field. In general, it was remembered by a terrible emotional state-it was felt that the answer was close, but everything was not glued.

In the Starobinsky model, something was missing at her beginning, at the start. The Guta model is very well justified, but does not work in its final stage. The success of Gut's work is not connected with what he traveled and told everywhere. He managed to light the audience with a clear detailed argument - a pure line of thought passes through the entire article. After his article, everything became transparent, despite the fact that the problem as a whole has not yet been resolved. Zeldovich was forced to say: "We have passed inflation!"

By the way, in America a wide public opinion about inflation stuck in 1981. According to popular articles and textbooks, Alan Gut is the only hero of the new cosmological paradigm. But he himself found that his theory does not work, and a year later he confirmed this conclusion.

- Did the new script arise next year?

- Yes, very soon. Igor Tkachev already partially spoke about what I was fighting at that time. Indeed, I tried to understand where the tunnel transition of the scalar field was taking place in the Gut script, while I had to use a computer with which I was not friendly. It turned out that sometimes the field jumps under the barrier almost horizontally - that is, it turns out to be high on the slope of potential. And then it is easier: it slowly rolls down the slope (the corresponding equation was known more than a hundred years ago - this is the equation of a harmonic oscillator with viscous friction), and while it rolls, the bubble manages to grow into an entire universe! But then why do you need a barrier at all? Let the field just rolling out from the gentle top ... It seemed that I was on the right track.

This was in the early summer of 1981, late June in the evening. The family has already slept. I took the phone and climbed into the bathroom with him, so as not to wake up children, call Rubakov and ask him what he thinks about this (there are people with whom you can’t share ideas, but there are those with whom you can without any fears). Valera replied that he hears about such a scenario for the first time and did not think about it himself. I reasoned that if he had not thought of that, then most likely no one thought of, and we must act urgently. I woke my wife and discussed all this with her. (Andrei’s wife is Renata Callosh, a well-known theoretic physicist working in the field of string theory.-B.Sh . ) very quickly wrote an article, sent to Glavlit, but the publication permission came only a few months later in October 1981.

At that time, a conference was held in Gaisha, which Stephen Hawking came to. I was asked to translate his report into Russian.

It looked like this: Hawking pronounced a word that only people who knew him could make out. This word "translated" into English a graduate student. And then I translated this word into Russian. This became depressing, and I began to run forward, extrapolating the speaker's speech. Hawking proved that the Guta model cannot be saved. He said that Linda had a wonderful idea of ​​how to do this, but it did not work, and the rest of the report I translated arguments why my idea could not work. In a more stupid state, I never was: the best physicists of Moscow were sitting in the hall, on which my future depended, and I scolded myself publicly with them.

After the report, I told Hawking that I did not agree with his argument, and explained to him for about two hours why my idea should still work. He listened carefully and from time to time said: “Oh!”, - and his student translated: “But you didn’t talk about it before!” Soon Hawking was grabbed by the frightened organizers of the conference. The loss of a foreigner, and even famous, was terrible! In the end, we were found in the audience near the board, apparently experiencing great relief.

After that, Hawking invited me to his hotel. The discussion continued, then he began to show photos of his family and invited me to a conference in Cambridge, which was mainly dedicated to my script. Several people from Russia went there, including us with Starobinsky. During the conference, we realized that the new inflation scenario, which I invented in 1981, needs to be changed.

- So far, it was about new inflation. How did chaotic?

-There was a problem with the new inflation: it was assumed that the inflatonal field responsible for inflating the Universe should first come to thermodynamic balance in order to be at zero, on the top of the hill, but there was very little time for this. And if the field did not have time to terminate and is somewhere on the slope of potential? I wrote the equations -I visited a simple solution: the field still manages to inflate the universe, if the potential is enough and the path down is quite long. It seems that you can do without thermalization. But this was a psychological problem: the universe should be hot initially - everyone is used to it! The idea of ​​a hot universe was close to everyone, and it was very difficult to abandon it.

Dictionary

Cosmological inflation is the process of exponential expansion of the universe, which took place within 10-35-10-33 C in front of a large explosion. In fact, this is the “initial impetus”, which gave rise to a huge homogeneous universe.

The world of de Sitter is the solution of Einstein's equations, which just describes the inflation process in its purest form. For its implementation, it requires a vacuum with a positive energy density and negative pressure p = -ε.

Gauses - mathematically determined as the absence of correlations between the phases of decomposition along orthogonal multiples. Physically, this means that a relict radiation map arose as the sum of the disturbances independent from each other.

The logic of chaotic inflation was this: let's not try to solve all issues at once. Suppose that nature has a choice - where to start. And if nature tries different options, then for sure those for which simple equations show the entrance to the inflation mode.

Most people were completely perpendicular to this idea. Here we are not talking about logic, but about psychology or even a social effect. People have been engaged in a hot universe for a long time and stubbornly, spent a lot of time and effort on this. And then someone is trying to say to them that this is all in vain, that everything works in a completely different way. The first natural reaction in this case is to send to sleep the one who says this. It’s the same as you break your house, which you have flooded.

-Well, now this main idea has become a common place.

- Now - yes, a common place, but then it was a painful fracture. Until now, most textbooks, speaking of inflation, present an old version based on the script of Guta and on my “new inflation”. Many did not understand that these two ideas died 30 years ago and were replaced by the idea of ​​chaotic inflation that I proposed in 1983. I experienced an even more difficult fracture in 1986.

- Eternal inflation?

- Yes. She opened painfully. But a moment of recognition was very clearly captured.

The first glimpses of eternal inflation appeared even at the level of the Gut model, but there it was a drawback. Then Paul Steinhardt noticed that in new inflation this also takes place. Immediately I released a preprint, where I claimed that it was just very interesting: all the time, while inflation continues, new universes arise with different properties. The same applied to the occasion of new inflation. It was 1982.

In 1983, Alexander Vilenkin made a more elegant work on the same topic. He showed that even if the field slid somewhere from the central hill, quantum fluctuations can abandon it back and inflation will continue.

Well, in 1986 there was a moment of crystallization: the same can be done in the framework of chaotic inflation! At first, it seemed madness - the same, the constant casting of the field up can occur on the slope of potential! Moreover, this revelation came at the time of the most severe mental crisis.

Then the Gorbachev perestroika has already begun, among other things, the restructuring of Glavlit in order to simplify. But the old system was closed, and the whole year was extended with the new one, and this year we could not publish articles. It was a heavy blow. In addition, I wrote a book, and it went badly-I had to rewrite something all the time, and then I had to do everything on paper with scissors and glue-replace the sheets, cross the links, which was out of the rut. To top it off, I learned to drive a car, and at that age Motorik is no longer the same as in my youth. And when I once again drove the car into a snowdrift, the instructors screamed at me obscenities. As a result, I was in very poor condition, I felt terribly, without strength. I could not do anything - lying on the couch and reading detectives.

At this time, they suddenly called Fian-we must go to Italy with a strange mission-to give popular lectures as part of some agreements. Moreover, lectures on astronomy, which is not my main specialty. At that time, an unspoken limit acted - one trip abroad per year. It was a pity to spend this chance on this. I decided to get out of illness, especially since I really felt completely sick. In the end, the certificate that I was sick signed Vitaly Ginzburg.

However, another call came soon. I was told: if you are sick today and are not able to recover by the time of the trip, then maybe you are not able to go abroad at all? I realized that the matter is serious. He got up, took a taxi, which at that time was a responsible financial decision for me, went to the clinic and, having gone in a day of all the doctors, received a certificate that I was absolutely healthy. After that, I lay down for two days, then I got up and in a day I designed all the papers, which was usually a month or two. They called me again and said that the Italians would like to see the text of my lectures. "When?" - "Tomorrow!"

All this looked like madness. But it occurred to me that there was a good side in this. During the year, I could not publish anything out of my works abroad, and now, if I do something interesting, they will send my work themselves without any Glavlite by diplomatic mail. It is stupid to miss this opportunity, but there is no need to print the old. What can I come up with a new one in half an hour to immediately print and send it tomorrow? I wrapped my arms around my head and began to swing from side to side: what can I come up with in half an hour?

And after half an hour I had the theory of eternal chaotic inflation. This was one of the most powerful emotional shocks of my life. Of course, I no longer had the strength to print it in one evening, but a month later, leaving to Italy, I had three new works on this topic, which I sent three different magazines from there. So it is likely to happen in life: when fate twists a person, squeezes him like a spring, if he does not break, then then straightens with the same force.

At first it seemed incredible: the inflaton field due to quantum fluctuations with sufficiently general assumptions can jump up the slope of the potential-up to the plank values ​​of the energy density. When the potential reaches meanings close to Plankovsky, large fluctuations of all other fields are excited. And this means that the vacuum can rebuild - the field will roll down again, inflating the space with another vacuum, with other laws of physics. As if the bandage from the eyes slept! The world changed, and it was a shock.

Я понял, что должен заново переписать книжку, над которой работал. В статье я писал, что не надо пытаться объяснять, почему мир именно таков, каким мы его видим. Когда-то Эйнштейн настаивал именно на таком подходе: нужно объяснить, почему законы физики и физические константы именно такие, какие есть, а другого не может быть. Но мир не единственен, и набор законов природы — тоже. Они таковы, потому что мы можем жить только там, где законы нам позволяют жить. Рыба может жить только в воде, мы — только на суше под слоем атмосферы, и так далее. Надо объяснять совсем другое: как образуется много разных частей Вселенной (или разных вселенных) с разной физикой, чтобы в каких-то из них могли жить мы или кто-то еще.

— Это было более четверти века назад. С тех пор кое-что изменилось, в том числе открыто ускоренное расширение Вселенной, которое можно назвать современной демонстрацией того, что механизм работает. Данные WMAP и «Планка» льют воду на ту же мельницу. Насколько вообще космологическая инфляция утвердилась в общественном сознании, и есть ли конкурентоспособные альтернативы?

— Как сказал Черчилль: «Демократия — худшая форма правления, за исключением всех остальных, которые пробовались время от времени». Конечно, в теории инфляции есть проблемы. И, конечно очень важно исследовать все возможные альтернативы — только после этого можно быть уверенным в теории. Очень интересно, если удастся найти нечто разумное.

Вопрос в том, как исследуются альтернативы. Если человек делает это честно, как, например Валера Рубаков, это очень полезная деятельность. А если человек просто делает карьеру на альтернативных теориях, это порой выглядит удручающе. Например, люди, занимающиеся альтернативными теориями, говорят: «Мы уже всё решили». Им указывают на конкретные ошибки. Через год они, слегка подправив модель, говорят: «Мы опять уже всё решили». And so on. Самое плохое в этом то, что таким образом отвращается от науки молодежь — наблюдая подобный цирк, легко прийти к заключению, что вся наука такова. Получается так, что одни занимаются физикой, а другие — обустройством социальной ниши.

Конечно же, нельзя исключить, что вдруг появится нечто, более мощное, чем теория инфляции. В этом случае я был бы первым, кто это приветствовал. И уж точно лучше не отсиживаться в кустах, подобно Остапу Бендеру, когда их догнал настоящий автопробег. Я бы чувствовал себя в подобной позиции отвратительно! Но пока на горизонте не видно ничего, что бы могло составить реальную конкуренцию. Кстати, еще один важный момент. В отличие от альтернативных моделей, в теории инфляции не важно, через что проходит Вселенная перед тем, как раздуться. Это может быть стадия сжатия некой предшествующей вселенной. Это может быть обычная космологическая сингулярность — инфляция стартует от состояния, близкого к планковскому, независимо от того, откуда последнее взялось.

Естественно, в теории есть неясные места. Никакая версия инфляции не идеальна. Основные проблемы начинаются при приближении к самому началу — к планковским масштабам. Но эти проблемы носят общий характер — как сшить гравитацию с квантовой механикой; какова роль теории струн? Мы привыкли работать в классическом времени, а как с ним работать в условиях квантовой гравитации в режиме, когда все часы и линейки немедленно ломаются, и говорить о «времени», когда родилась Вселенная, становится трудно?

— Наконец, благодаря WMAP и «Планку» дошло дело до того, что данные позволяют выбирать между разными версиями инфляции. Найдут ли все-таки гравитационные волны и на каком уровне?

— Не так давно делались ставки, что отношение амплитуды гравитационных волн к амплитуде скалярных возмущений, обозначаемое как r, будет найдено на уровне 15%. Есть несколько вариантов теории, которые предсказывают отношение r на уровне 3…4 x 10-3.

— Так это ровно то, что называл Алексей Старобинский для своей модели — полпроцента!

— Да, но тут не только его модель, что само по себе является удивительным. Например, Михаил Шапошников с Фёдором Безруковым придумали хиггсовскую инфляцию, где инфлатоном выступает поле Хиггса, но не просто так, а имея неминимальное взаимодействие с гравитацией. Их модель совершенно не похожа на модель Старобинского. А предсказания дает точно такие же. И не они одни. Например, мы с Ренатой Каллош тоже пробовали строить разные потенциалы на основе супергравитации и нашли огромный класс теорий с такими же предсказаниями. Может быть, в этом странном факте заключена какая-то важная подсказка, которую мы пока не понимаем?

— Дойдут ли наблюдатели до этого уровня?

- Maybe. Причем, скорее, на наземных установках. Их преимущество перед космическими экспериментами — возможность неограниченного наращивания. Появились новые деньги — поставили новые приемники в дополнение к старым — точность возросла. Правда, подавляющее большинство суперструнных моделей инфляции дает вообще безнадежно малый вклад гравитационных волн — ниже порога регистрации любого мыслимого эксперимента.

Что касается данных «Планка» -с ними связана довольно драматическая история. Простые и наиболее естественные модели инфляции говорят, что реликтовое излучение должно быть с хорошей точностью гауссовым. Тем не менее, существуют модели инфляции с несколькими взаимодействующими друг с другом полями, где гауссовость нарушается. Людей, занимающихся такими моделями, много — это достаточно широкая социальная ниша.

В какой-то момент пошли слухи, что команда WMAP намерила отклонение от гауссовости. Народ из вышеупомянутой ниши взбодрился. Я позвонил одному из членов команды, он сказал, что слышит такое впервые, — никаких отклонений они не видят. Мы, затаив дыхание, ждали результатов «Планка». Жили, как на вокзале, — пока не было ответа наблюдателей, рот был заткнут. Наконец в марте прошлого года космологические результаты «Планка» были опубликованы. Практически никаких отклонений от гауссовости, предсказания простейших моделей инфляции подтверждены.

Люди, занимающиеся сложными моделями инфляции, были несчастны. А для нас — как будто плотину прорвало! Значит, можно ничего не бояться и продолжать заниматься тем, что представляется наиболее красивым и естественным.

— Так, пожалуй, это и есть главный результат «Планка» на данный момент. В остальном — только уточнение относительно WMAP.

— Согласен, это и есть главный результат.

PS На этом интервью завершилось без пафосно закругляющегося конца, поскольку оба устали — Андрей устал говорить, а автор, принципиально не пользующийся электронной записью, устал воспринимать и фиксировать сказанное закорючками на бумаге.

PPS Интервью было взято до объявления результатов по обнаружению гравитационных волн экспериментом BICEP2 в Антарктиде (см. ТрВ-Наука, № 150). Вот что Андрей написал вдогонку: «Недавние результаты полученные на установке BICEP2 рядом с Южным Полюсом показывают, что амплитуда гравитационных волн может оказаться очень большой, вплоть до r = 0,2, близко к тому, что предсказывают простейшие варианты хаотической инфляции. Если эти результаты подтвердятся, то это достижение будет сопоставимо по значению с открытием бозона Хиггса. Но пока еще рано подводить итоги. Нужно провести независимую проверку и понять причины разницы в результатах BICEP2 и предыдущих попыток найти сигнал от гравитационных волн. Одно несомненно: мы живем в эпоху великих космологических открытий!»