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The author discusses states of matter other than solids, liquids, and gases that arise from transitions among electrons in materials that can be described in part by string theory and quantum physics. He describes the applicability of quantum entanglement in explaining the instantaneous anticorrelation communications that appear to occur between electrons. Topics include the theory of gravitation developed by the physicist Albert Einstein, crystal structures, superconductors, black holes, and collaboration between specialists in string theory and condensed matter. The impact of electron spin on barium iron arsenide is mentioned.

The article discusses the Big Bang theory, which is a theory of cosmic inflation first proposed by astronomer Alan Guth in 1980. Topics include the theory of cosmic inflation, which states the universe expanded faster than the speed of light a fraction of a second after the big bang, the value of the inflation theory in helping astronomers understand the cosmos, and physicist Paul Steinhardt's alternative to the inflation theory, called the cyclic universe theory, which is based on the string theory. Also discussed is the logical self-destruction of the inflation theory and a no-boundary proposal of the universe by physicists Stephen Hawking and James Hartle.

The article looks at developments in cosmology and the possible existence of other universes in a multiverse cosmos. Topics include a history of cosmological theory with a focus on the work of physicist Albert Einstein, the expansion of the universe and inflationary cosmology, the shortcomings of the big-bang theory, the repulsive gravity of dark energy, the multiverse solution to the mystery of dark energy, and the attempt of string theory to unify all matter and forces into a single mathematical reality.

The article explores the concept of the multiverse, the idea that our universe is one of many other universes. Various theories about the nature of the multiverse are presented, including whether other universes are duplicates of ours or different, whether universal inflation infers multiple universes that share our universe's laws and constants, and the implications of string theory on a hierarchy of universes.

The article discusses the scientific idea behind the multiverse, or the cosmological concept that billions of other universes exist. Explanations behind the idea, including chaotic inflation, string theory, and levels of the multiverse, are discussed. Arguments of cosmologists on topics such as space infinity, physics theories, and concepts about fundamental constants are explored. Topics include extrapolation and metaphysical issues, the need for observational testing, and the lack of solid evidence about the multiverse. INSETS: IN BRIEF;Does the Glove Fit?.

The article reports how a forgotten number system invented in the 19th century, called octonions, may provide the simplest explanation for why the universe could have ten dimensions. The authors note that octonions have established a place in string theory and that if the string theory is a correct representation of the universe, it could explain the number of dimensions the universe contains. Topics include the relationship of real and imaginary numbers, such as octonions, how imaginary numbers can be thought of as geometric manipulations, and how octonions can advance the understanding of particle physics research in the fields of supersymmetry and string theory. INSETS: Math in Multiple Dimensions;The Problem with Rotations.

An essay is presented, which is based on the book "The Grand Design," by Stephen Hawking and Leonard Mlodinow, in which physicists Hawking and Mlodinow argue that the quest to find a final theory to everything may not lead to a unique set of equations. Topics include an overview of how physicists are using the string theory to try and reconcile Albert Einstein's theories of gravitation and quantum physics into a final theory of everything and why it is flawed.

The article discusses the possibility of the existence of a fifth force that may help explain the mysteries of dark energy. Topics include a brief overview of the basic theory of a fifth force, which was postulated by astrophysicists Justin Khoury and Amanda Weltman, an explanation of the string theory, from which the fifth force was devised, and how the changing masses of chameleon particles could help explain dark energy.

An interview is presented with mathematician Shing-Tung Yau, best known for developing the math behind string theory, which suggests the universe is comprised of 10-dimensional vibrating strings. Yau comments on his interest in topology as a way to reveal the structure of space. He also discusses how the underlying structure of space may explain the laws of physics, and the importance of complex manifolds and complex numbers in understanding space.

The article analyzes the importance of studying quantum gravity. It states that all the fundamental forces of nature except gravity can be defined by the exchange of force-carrying particles that observe the rules of quantum theory. However, it notes that a quantum theory of gravity is needed to present an overarching theory of the workings of the world and its origin. It describes the string theory and the loop quantum gravity. A comment from Giovanni Amelino-Camelia of Sapienza University of Rome is included.

The article discusses string theory, touted as a theory of everything, and the application of its mathematical tools to explain some of the most complex yet useful types of material on Earth. The mathematical tools were originally designed for the study of the cosmos. Argentinian physicist Juan Maldacena was able to connect a condensed-down string theory with a normal field theory of particle interactions.

This article presents an interview with cosmologist Max Tegmark in which he discusses his views on parallel worlds, multiple dimensions, and alternative universes. Tegmark explains how his work has been labeled as too speculative, and how he has had to focus on his mainstream ideas in order to get jobs. His theory of a level four universe that is purely mathematical has received the most attention.

The article focuses on cosmic strings, a line of energy billions of light years long. It is narrower than a proton and so dense that it weighs similar to a continent in a size of one meter. Cosmic strings are cousins of superstrings, which is believed to make up all matter. Cosmologists mention that cosmic string could be credited for about 10 percent of the universe's structure.

The article discusses the string theory of Laura Mersini-Houghton of the University of North Carolina and collaborator Richard Holman of Carnegie Mellon University as a way of explaining a void in the universe which is 900 million light years across. The void was discovered in August 2007 by Lawrence Rudnick, Shea Brown and Liliya Williams of the University of Minnesota who were analysing a survey of radio-emitting galaxies carried out by the Very Large Array of telescopes at the National Radio Astronomy Observatory.

The article discusses a theory that combines the principles of sting theory and the cosmic inflation theory. The author explains that ideas are being proposed about the universe being apart of a "multiverse" which contains many universes all interacting with one another. This could explain why our universe is slowing down and may also suggest that it will speed up when the right forces act on it. INSETS: MANY UNIVERSES IN ONE;STRINGLISH;Why Is Our Universe 3-D?.

The article discusses scientists' efforts to find the elusive "theory of everything" which would unite the theory of relativity with subatomic theory. String theory was created in the 1970s and posits that the laws of physics may be dictated by the complex movements of string-like particles acting in a nine-dimensional universe. Theorist Joe Polchinski's efforts to test whether string theory works by using cosmological data are discussed.

The article discusses the debate over the string theory and a theory of everything. The cynics claim that no matter how many slick TV documentaries or breathless articles appear on string theory, the fact is that a direct test is impossible. The defenders of the theory cite a series of experiments that may in the coming years probe the periphery of string theory, through cosmic rays and the Large Hadron Collider near Geneva, Switzerland.

Examines the claims regarding string theory. Sources of gravity waves; Description and function of the Large Hadron Collider; Materials used by different countries in capturing dark-matter particles.

The article reports that particles created in the big bang flew apart, eventually combining into larger particles, atoms, planets, trees and people as the universe expanded. For years, physicists have used this analogy between atom smashers and the universe as a guiding principle towards the elusive theory of everything. The main reason for this is that the atom smasher idea happens to fit well with string theory, the theory that replaces subatomic particles with tiny vibrating strings, and is supposed to describe the whole universe and unify all of physics.

The article discusses whether physical constants of nature are really constant. Physicists call them the constants of nature. Such quantities as the velocity of light, Newton's constant of gravitation, and the mass of the electron are assumed to be the same at all places and times in the universe. The desire to explain the constants has been one of the driving forces behind efforts to develop a complete unified description of nature, or "theory of everything." Researchers have found that the best candidate for a theory of everything, the variant of string theory called M-theory, is self-consistent only if the universe has more than four dimensions of space and time. So far string theory offers no explanation for the observed values of the constants. Astronomy entered the constants story soon after the discovery of quasars. Because the path of light from a quasar to us is so long, it inevitably intersects the gaseous outskirts of young galaxies. That gas absorbs the quasar light at particular frequencies, imprinting a bar code of narrow lines onto the quasar spectrum. Based on a total of 128 quasar absorption lines, we found an average increase in a of close to six parts in a million over the past six billion to 12 billion years. If so, we must confront the likelihood that α really has been changing.

The article presents the author's opinions about the string theory related to the universe. In string theory, there is a startling new picture: the subatomic particles of the universe, that is, electrons, quarks, and neutrinos; are all different resonances of a string vibrating much like a rubber band. Each "note" of the string represents a different subatomic particle. For thousands of years, it was assumed that all matter could be broken down to points, not strings. This string picture is so different that it could only have been discovered by accident. And the new theory allows the whole of physics to be reduced to the harmonies of these strings. The whole universe consists of a symphony of strings.

This is an article that analyses string theory in relation to the universe. According to string theory, the laws of physics that we see operating in the world depend on how extra dimensions of space are curled up into a tiny bundle. The Kaluza-Klein idea has been resurrected and extended as a feature of string theory, a promising framework for the unification of quantum mechanics, general relativity and particle physics. The key question is, What determines this geometry? Because there is more than one parameter, we should actually think of this vacuum energy curve as one slice through a complex, multidimensional mountain range, which Leonard Susskind of Stanford University has described as the landscape of string theory see middle illustration on page 85. With the advent of quantum field theory, empty space-the vacuum--became a busy place, full of virtual particles and fields popping in and out of existence, and each particle and field carries some positive or negative energy. INSETS: Strings and Tubes;The Hidden Space;Topography of Energy;Bubbles of Reality

Presents an interview with Lawrence M. Krauss, the chair of the physics department at Case Western Reserve University. Opinion of Krauss that string theory has failed to shed light on the nature of dark energy; Discussion of his book "The Physics of Star Trek"; Lack of scientific knowledge in society; Fight of Krauss against creationist teachings in the schools.

Most people have at least heard of string theory, even if their ideas about what it actually is may be a bit vague. One of the most widely publicised aspects of string theory is its need for extra "tiny" dimensions of space. But in the last few months there have been developments that are quietly beginning to do away with the need for these extra dimensions. The fantastical but perhaps appealingly exotic idea that the universe has myriad extra dimensions on top of the four experienced may soon be considered rather dated.

The article focuses on whether the big bang was really the beginning of time. After string theory made its comeback as a theory of gravity in the 1980s, it was applied to black holes and cosmology. Conditions near the zero time of the big bang were so extreme that no one yet knows how to solve the equations. Nevertheless, string theorists have hazarded guesses about the pre-bang universe. Two popular models are floating around. The first, known as the pre-big bang scenario combines T-duality with the better-known symmetry of time reversal, whereby the equations of physics work equally well when applied backward and forward in time. The other leading model for the universe before the bang is the ekpyrotic ("conflagration") scenario. The pre-big bang and ekpyrotic scenarios share some common features. Both begin with a large, cold, nearly empty universe, and both share the problem of making the transition between the pre- and the post-bang phase. Mathematically, the main difference between the scenarios is the behavior of the dilaton field. Like the details of the inflationary phase, those of a possible pre-bangian epoch could have observable consequences, especially for the small variations observed in the cosmic microwave background temperature. Analysis of the microwave background is not the only way to verify these theories. The pre-big bang scenario should also produce a random background of gravitational waves in a range of frequencies that, though irrelevant for the microwave background, should be detectable by future gravitational-wave observatories. Moreover, because the pre-big bang and ekpyrotic scenarios involve changes in the dilaton field, which is coupled to the electromagnetic field, they would both lead to large-scale magnetic field fluctuations. Vestiges of these fluctuations might show up in galactic and intergalactic magnetic fields.

Maybe cosmic acceleration isn't caused by dark energy after all but by an inexorable leakage of gravity out of our world. Cosmologists and particle physicists have seldom felt so confused. Although our standard model of cosmology has been confirmed by recent observations, it still has a gaping hole: nobody knows why the expansion of the universe is accelerating. Researchers commonly attribute the acceleration to some mysterious entity called dark energy, but there is little physics to back up these fine words. The only thing that is becoming clear is that at the largest observable distances, gravity behaves in a rather strange way, turning into a repulsive force. The laws of physics say that gravity is generated by matter and energy, so they attribute a strange sort of gravity to a strange sort of matter or energy. Over the years, physicists have come up with a few plausible approaches to quantum gravity, the most prominent being string theory. When Astronomers encountered the cosmic acceleration, their first reaction was to attribute it to the so-called cosmological constant. To get around this problem, a number of physicists have proposed that the acceleration is caused not by space itself but by an energy field that suffuses space like a thin fog. INSETS: FROM FLATLAND TO FOUR DIMENSIONS;THREE WAYS TO ADD A DIMENSION;THE SURLY BONDS OF BRANES;THE POLARIZED BRANE

Presents an interview with Brian Greene, a physics professor at Columbia University. His contributions to the popular understanding of the string theory; Importance of the fundamental discoveries about the universe and general relativity; Consideration of Greene's book 'The Elegant Universe' which was a finalist for the Pulitzer Prize; Equations involving the impact of spacetime on true quantum theories of gravity; Relationship between physics and geometry; Development of anthropic ideas.

String theory is the most ambitious attempt of theoretical physicists to explain the laws of nature. Based on the idea that elementary particles have an extended structure that resembles tiny loops of string, it has the potential to unify all the forces in nature, including the elusive quantum theory of gravity. The cosmological constant represents an energy content of the vacuum and empty space. That may sound like an oxymoron, empty space having energy, but in modern physics the vacuum is a complicated object in which violent quantum fluctuations are continually taking place. Electrons, positrons, photons and all the other elementary particles are constantly being created and annihilated so quickly that to our slow ponderous detectors they are usually invisible. But they are there and they give rise to an energy density in what we ordinarily think of as empty space. The terms vacuum energy density and cosmological constant mean the same thing and are used interchangeably. Then, why does such vacuum energy make a difference? If it is always there in the background why don't we reset the zero of energy and just ignore it? The answer lies in the theory of gravitation. According to physicist Isaac Newton, the measure of an object's gravitational potency is its mass. Physicists describe this by saying that mass is the source of the gravitational field in much the same way that electric charge is the source of the electric field. Thus the gravitational field surrounding the sun is about a million times the field of the Earth because the sun is a million times more massive. But according to physicist Albert Einstein, mass and energy are really the same thing. Every object has an energy content given by the formulae, E = mc[sup2]. Therefore, we can consider the gravitational field to be a response to the presence of energy.

Focuses on efforts by theoretical physicists to prove the existence of unseen dimensions in the universe. Need of the string theory for six extra space dimensions; Existence of dark matter; Potential benefits of the study of the unseen dimensions.

Focuses on the theory by Gabrielle Veneziano of the European Laboratory for Particle Physics that the universe began long before the Big Bang. Problems inherent in the original Big Bang model, such as singularity; Application of the string theory to the Big Bang Theory; Use of quantum mechanics to explain the origin of particles such as electrons, positrons, and photons; Perceived problems with the pre-Big Bang scenario.