Chaotic inflation, and another leading model, new inflation, both appear to result in eternal inflation. The inflation theory it proposes a period of extremely rapid exponential expansion of the universe prior to the more gradual big bang expansion, during which time the energy density of the universe was dominated by a cosmological constant type of vacuum energy that later decayed to produce the matter and radiation that fill the universe today. The theories of eternal inflation and chaotic inflation in string theory can be quite confusing. It is really only the theory of the aftermath of a bang. This ties into string theory models which admit of a very large number of possibilities for physical parameters. Looking backwards in time, the big bang model says that the universe becomes radiationdominated and that the densitytemperature increase unboundedly in finite time, leading to the big bang. Eternal inflation is an extension of the big bang theory which results in the existence of a mul. Stephen hawkings breathtaking final multiverse theory. The usual theory of in ation breaks down in eternal in ation.
We define the euclidean dual theory on the threshold surface of eternal inflation, which therefore describes the transition from the quantum realm. A reliable theory of eternal in ation is important to sharpen the predictions of slow roll in ation. T h e inflationary universe scenario an d q u an tu m cosm ology 1 4. The unique universe a smooth exit from eternal inflation.
Eternal inflation is a hypothetical inflationary universe model, which is itself an outgrowth or extension of the big bang theory according to eternal inflation, the inflationary phase of the universes expansion lasts forever throughout most of the universe. Andrei linde brief history of the multiverse centre for theoretical. Andrei linde is another one of the fathers of inflationary big bang theory, and the originator of the chaotic inflation models. If true, eternal inflation would mean that everything that we see, plus a huge amount that we dont see hidden behind our cosmological horizon, all came from a single bubble amongst an infinity of other bubbles. Reinhardt has two main objections to the status of the theory he fathered, the first is the goldilocks problem about the number of ways in which inflation could have gone wrong, which brings us back to the anthropic principle, and the second is that perpetual inflation into the future presents us with the same problem boltzmann gave us. Eternal inflation uvafnwi universiteit van amsterdam. Based on the phrase multiple big bangs i did not think that was what was being described here. Inflation theory brings together ideas from quantum physics and particle physics to explore the early moments of the universe, following the big bang. Because the regions expand exponentially rapidly, most of the volume of the universe at any given time is inflating. Moreover, this reheating may be only local, so that inflation continues elsewhere and forever, continually spawning bigbanglike regions. Apr 27, 2018 the usual theory of inflation breaks down in eternal inflation. In eternal inflation, the quantum fluctuations in the. The partition function gives the amplitude of di erent geometries of the threshold surface in the noboundary state.
The cosmological model of eternal inflation and the. A smooth exit from eternal inflation request pdf researchgate. While the big bang theory successfully explains the. We have discussed the three main planks of evidence for the big bang model. This was confusing from the op, but inflationary theory is the theory that at the beginning, the universe had a period of incredible inflation 1026 in only a small fraction of a second. So, in particular, the standard big bang theory does not address the question of what caused theexpansion. Eternal inflation and the multiverse dark matter, dark. Its local and global behavior in dual toy models shows that the amplitude is low. When people say multiverse i usually immediately think of the many worlds interpretation of quantum mechanics in which every possible reality in the copenhagen interpretation of a system actually does exist. Eternal inflation is therefore a theory of many bubble universes individually nucleating and growing inside an everexpanding background multiverse. Although the infinity of pocket universes produced by eternal inflation are unobservable, it is argued that eternal inflation has real consequences in terms of the way that predictions are. Jan 12, 2018 inflation is one of the most famous, wellaccepted, and relatively new cosmological theories, and its part of the many cosmological theories. Whatever that theory is, it has to somehow explain the number of particles, 1090 or more. The theory of eternal inflation casts our universe as one of countless bubbles in an eternally frothing sea.
Following the inflationary period, the universe continued to expand, but. Eternal inflation is a hypothetical inflationary universe model, which is itself an outgrowth or. The prospects of inflationary cosmology as a viable theory would be greatly advanced if it could be established that pocket universes very much. In fact, it is easy to construct underlying particle theories that will give far more than 70 efoldings of inflation. Does the theory of eternal inflation now best explain. Worse, inflation goes on eternally, producing infinitely many outcomes, so the theory makes no firm observational predictions. However, for nearly two decades this theory was followed only by few experts in in. Eternally existing selfreproducing chaotic inflationary universe pdf. Scientists debate among and within themselves whether these troubles are teething pains or signs of a deeper rot. The oscillating universe theory is a cosmological model that combines both the big bang and the big crunch as part of a cyclical event. Once the inflation field gets triggered, it will continue the inflationary process for eternity, no matter how it got started. It is not merely the prediction of some specific theory, but it is the generic prediction for a wide class of plausible theories. If true, eternal inflation would mean that everything that we see, plus a huge amount that we dont see hidden behind our cosmological horizon, all came from a single bubble amongst an infinity. We derive a dual description of eternal inflation in terms of a deformed cft located at the threshold of eternal inflation.
We derive a dual description of eternal inflation in terms of a deformed ir cft located at the threshold of eternal inflation. Subscribe to our youtube channel for all the latest. Aug 24, 2009 the oscillating universe theory is a cosmological model that combines both the big bang and the big crunch as part of a cyclical event. The usual theory of inflation breaks down in eternal inflation. It simply states that once inflation happens, it produces not just one unive. It does not rule out the possibility of stochastic inflation, nor does the paper make any claims about the universe blowing up. T h e oscillating inflationary universe an d gravitational confinem ent a p p en d ix 2. The eternal inflation model is a modification of this model which solved the graceful exit problem. Feb 05, 2015 it does not rule out the possibility of stochastic inflation, nor does the paper make any claims about the universe blowing up. The difficulty in actualizing eternal inflation originates from the breaking of two underlying symmetries. There reason of thinking is since we cant prove the existence of everything is because the being that contain our brains doesnt want us to.
T h e in flation ary u n iverse stanford university. Eternal inflation is a hypothetical inflationary universe model, which is itself an outgrowth or extension of the big bang theory. Dec 06, 2015 it appears that eternal inflation is not eternal into the past, however, just into the future see guth paper referenced below. Testing the multiverse hypothesis requires measuring whether our universe is statistically typical among the infinite variety of universes. Jan 29, 2019 inflation theory brings together ideas from quantum physics and particle physics to explore the early moments of the universe, following the big bang.
It was developed around 1980 to explain several puzzles with the standard big bang theory, in which the universe expands relatively gradually throughout its history. After the big bang, the universe experienced a period of exponential inflation. Essentially all inflationary models lead to a regime called eternal inflation, a situation where inflation never ends globally, but it only ends locally. The phase transition to slowroll eternal inflation. Lorentz invariance and the general covariance of the theory which lead to an. Taming the multiversestephen hawkings final theory about. If modern physics is to be believed, we shouldnt be.
Inflation is one of the most famous, wellaccepted, and relatively new cosmological theories, and its part of the many cosmological theories. Furthermore, the populated landscape version of string theory independently yields a very similar model of the multiverse 811. Then it slowed down, and the energy converted into matter and radiation. Pdf a conformal field theory for eternal inflation. In physical cosmology, cosmic inflation, cosmological inflation, or just inflation, is a theory of exponential expansion of space in the early universe. Under a variation of the theory that hawking and hertog work with, called eternal inflation, this inflation continues forever in most places, but, in some patches, it stops. The theory of eternal inflation that hawking and hertog put forward is based on string theory. We derive a dual description of eternal in ation in terms of a deformed euclidean cft located at the threshold of eternal in ation. Hawking, thomas hertog submitted on 24 jul 2017 v1, last revised 4 mar 2018 this version, v2 the usual theory of inflation breaks down in eternal inflation.
According to inflation theory, the universe was created in an unstable energy state, which forced a rapid expansion of the universe in its early moments. Aug 01, 2017 cosmic inflation theory, first proposed by alan guth in 1981, modified the big bang theory the standard model by proposing that the universe, instead of unfolding at a steady pace, expanded rapidly shortly after it was created, which could account for apparent finetuning. Inflation is a paradigm for the physics of the early universe, and it has received a great deal of experimental support. The inflation theory proposes a period of extremely rapid exponential expansion of the universe during its first few moments. Inflation is not the only naturalist theory on offer. Brain in the vat theory this theory says that our brains are in a vat and being manipulated by alien or scientist in an external world.
According to inflation theory, the universe was created in an unstable energy state, which forced a. Subsequent developments included the detailed theory of eternal in. The mechanisms that lead to eternal inflation in both new and chaotic models are described. This is the general scheme of chaotic inflation as it. Eternal inflation theory by sunshine eaton on prezi. In the original version of the inflationary theory guth 1981, the state that drove the. Cosmological inflation is an addition to the highly successful big bang model of the universe. In this section i discuss the mechanisms that make eternal in. According to eternal inflation, the inflationary phase of the universes expansion lasts forever throughout most of the universe.
The fe ermangraham expansion implies that in terms of the variable rthe asymptotically lorentzian ds domain of the theory is to be found along the vertical line. Inflation, or the inflationary universe theory, was originally developed as a way to overcome the few remaining problems with what was otherwise. However, according to the theory of eternal inflation, some bubbles of space stopped. Eternal inflation is an extension of the big bang theory which results in the existence of a multiverse but there is no hard evidence that it does, or must, exist. What stephen hawkings final paper says and doesnt say.
In essence, all this paper is really saying is that the chaotic inflation theory does not create eternal inflation, and therefore no multiverses are created. Eternal inflation otoh is not cyclic, though its selfsimilar. Subsequent developments included the detailed theory of eternal inflation in the new inflation scenario vilenkin 1983 and the theory of eternal chaotic inflation. Jan 21, 2014 eternal inflation is therefore a theory of many bubble universes individually nucleating and growing inside an everexpanding background multiverse.
Eternal inflation and string theory landscape andrei linde. However, according to the theory of eternal inflation, some bubbles of space stopped inflating or slowed on a stopping trajectory, creating a small fractal deadend. Most people, even physicists, use them fairly interchangeably. We derive a dual description of eternal inflation in terms of a deformed ir cft located at the. The partition function gives the amplitude of different geometries of the threshold surface in the noboundary state. We derive a dual description of eternal inflation in terms of a deformed euclidean. Thus, although the model of eternal inflation cannot be considered proved, this is the strongly preferred current scenario of the cosmic evolution.
Eternal inflation, also known as chaotic inflation, is the most widely currently accepted theory of inflation. Since this question has already been answered in detail by others, this is my attempt to write a very simple and easytounderstand response. These leave little room for doubt that the basic model is correct. Stephen hawkings final theory about our universe has just. Cosmic inflation theory loses hangups about scientific method. That is, if this theory holds true, then the universe in.
In this model, parts of the universe are always in this false vacuum phase, and thus inflate. Note also that eternal inflation is thought to be eternal only into the future, not into the past, whereas a really periodic universe like penroses would be eternal into the past and into the future. The theory describes how the matter evolved from one form to another as the universe evolved, but the theory does not address the question of how the matter originated. In particular a quantum model of eternal in ation speci es a prior over the socalled zero modes, or classical slow roll backgrounds, in the theory. This is because the physics of eternal in ation speci es initial conditions for classical cosmology.
Dec 20, 2010 eternal inflation otoh is not cyclic, though its selfsimilar. A conformal field theory for eternal in ation by eudald correig fraga the study of the dynamics of the universe is one of the biggest goals in physics. The difference is that in eternal inflation, the growth need not have stopped all at once. If inflation really is eternal, and thus goes on forever, then over time it would create an infinite number of. Various proposals are circulating for ways to fix inflation or replace it. Indeed, its the speculative theory that universes can spontaneously appear out of nothing, possibly but not necessarily from a region in an existing universe.
This is an excellent example of how concepts on the cutting edge of science can get blurred, even between different experts in the field. Each of these miniuniverses could have different values of the fundamental physical parameters. We derive a dual description of eternal inflation in terms of a deformed euclidean cft located at the threshold of eternal inflation. This volume is the only monograph covering the exciting and dazzling recent developments in quantum cosmology, including the theory of the multiverse and eternal inflation pioneered by a vilenkin, a linde, s w hawking, and others. May 02, 2018 the theory of eternal inflation that hawking and hertog put forward is based on string theory. Eternal inflation in stringy landscapein stringy landscape. Jhep042018147 where r is the overall radial coordinate in euclidean ads, with scale factor er. May 02, 2018 its based around a concept called eternal inflation, first introduced in 1979 and published in 1981. Apr 16, 2010 the inflation theory proposes a period of extremely rapid exponential expansion of the universe during its first few moments. Eternal inflation and its implications princeton physics. Thus, we are led to at least think about a theory that might explain how the universe got to be so big.