Jazz Latin New Age. Aggressive Bittersweet Druggy. Energetic Happy Hypnotic. Romantic Sad Sentimental. Sexy Trippy All Moods. Drinking Hanging Out In Love. Introspection Late Night Partying. Want more? Advanced embedding details, examples, and help! To use this MP3 or any of Technetium's other tracks for commercial applications, please contact technetiummusic aol.
River Deep, Mountain High. Tin Soldier. Steve Marriott. Black Hole Sun. Chris Cornell. Summer In The City.
You're No Good. Clint Ballard, Jr. I just about played that CD to death, and I have picked up close to a dozen more albums by Mick and the guys since then, in a variety of bands and permutations. Over a year time span, as recounted on his website, www. From this body of work, he pieced together his first solo album in , Pick up the Phone, America! In order to describe real physical phenomena using string theory, one must therefore imagine scenarios in which these extra dimensions would not be observed in experiments.
Compactification is one way of modifying the number of dimensions in a physical theory. In compactification, some of the extra dimensions are assumed to "close up" on themselves to form circles. A standard analogy for this is to consider a multidimensional object such as a garden hose. If the hose is viewed from a sufficient distance, it appears to have only one dimension, its length.
However, as one approaches the hose, one discovers that it contains a second dimension, its circumference. Thus, an ant crawling on the surface of the hose would move in two dimensions. Compactification can be used to construct models in which spacetime is effectively four-dimensional. However, not every way of compactifying the extra dimensions produces a model with the right properties to describe nature.
In a viable model of particle physics, the compact extra dimensions must be shaped like a Calabi—Yau manifold. Another approach to reducing the number of dimensions is the so-called brane-world scenario. In this approach, physicists assume that the observable universe is a four-dimensional subspace of a higher dimensional space.
In such models, the force-carrying bosons of particle physics arise from open strings with endpoints attached to the four-dimensional subspace, while gravity arises from closed strings propagating through the larger ambient space.
This idea plays an important role in attempts to develop models of real world physics based on string theory, and it provides a natural explanation for the weakness of gravity compared to the other fundamental forces.
A notable fact about string theory is that the different versions of the theory all turn out to be related in highly nontrivial ways. One of the relationships that can exist between different string theories is called S-duality. This is a relationship that says that a collection of strongly interacting particles in one theory can, in some cases, be viewed as a collection of weakly interacting particles in a completely different theory.
Roughly speaking, a collection of particles is said to be strongly interacting if they combine and decay often and weakly interacting if they do so infrequently. Type I string theory turns out to be equivalent by S-duality to the SO 32 heterotic string theory. Similarly, type IIB string theory is related to itself in a nontrivial way by S-duality. Another relationship between different string theories is T-duality. Here one considers strings propagating around a circular extra dimension.
For example, a string has momentum as it propagates around a circle, and it can also wind around the circle one or more times. The number of times the string winds around a circle is called the winding number. If a string has momentum p and winding number n in one description, it will have momentum n and winding number p in the dual description. For example, type IIA string theory is equivalent to type IIB string theory via T-duality, and the two versions of heterotic string theory are also related by T-duality.
In general, the term duality refers to a situation where two seemingly different physical systems turn out to be equivalent in a nontrivial way. Two theories related by a duality need not be string theories. For example, Montonen—Olive duality is example of an S-duality relationship between quantum field theories. If two theories are related by a duality, it means that one theory can be transformed in some way so that it ends up looking just like the other theory.
The two theories are then said to be dual to one another under the transformation. Put differently, the two theories are mathematically different descriptions of the same phenomena. In string theory and other related theories, a brane is a physical object that generalizes the notion of a point particle to higher dimensions. For instance, a point particle can be viewed as a brane of dimension zero, while a string can be viewed as a brane of dimension one.
It is also possible to consider higher-dimensional branes. In dimension p , these are called p -branes. The word brane comes from the word "membrane" which refers to a two-dimensional brane. Branes are dynamical objects which can propagate through spacetime according to the rules of quantum mechanics.
They have mass and can have other attributes such as charge. Physicists often study fields analogous to the electromagnetic field which live on the worldvolume of a brane. In string theory, D-branes are an important class of branes that arise when one considers open strings.
As an open string propagates through spacetime, its endpoints are required to lie on a D-brane. The letter "D" in D-brane refers to a certain mathematical condition on the system known as the Dirichlet boundary condition. Branes are frequently studied from a purely mathematical point of view, and they are described as objects of certain categories , such as the derived category of coherent sheaves on a complex algebraic variety , or the Fukaya category of a symplectic manifold.
Prior to , theorists believed that there were five consistent versions of superstring theory type I, type IIA, type IIB, and two versions of heterotic string theory. This understanding changed in when Edward Witten suggested that the five theories were just special limiting cases of an eleven-dimensional theory called M-theory.
His announcement led to a flurry of research activity now known as the second superstring revolution. In the s, many physicists became interested in supergravity theories, which combine general relativity with supersymmetry.
Whereas general relativity makes sense in any number of dimensions, supergravity places an upper limit on the number of dimensions. Initially, many physicists hoped that by compactifying eleven-dimensional supergravity, it might be possible to construct realistic models of our four-dimensional world.
The hope was that such models would provide a unified description of the four fundamental forces of nature: electromagnetism, the strong and weak nuclear forces , and gravity. Interest in eleven-dimensional supergravity soon waned as various flaws in this scheme were discovered. One of the problems was that the laws of physics appear to distinguish between clockwise and counterclockwise, a phenomenon known as chirality. Edward Witten and others observed this chirality property cannot be readily derived by compactifying from eleven dimensions.
In the first superstring revolution in , many physicists turned to string theory as a unified theory of particle physics and quantum gravity. Unlike supergravity theory, string theory was able to accommodate the chirality of the standard model, and it provided a theory of gravity consistent with quantum effects.
In ordinary particle theories, one can consider any collection of elementary particles whose classical behavior is described by an arbitrary Lagrangian. In string theory, the possibilities are much more constrained: by the s, physicists had argued that there were only five consistent supersymmetric versions of the theory.
Although there were only a handful of consistent superstring theories, it remained a mystery why there was not just one consistent formulation. They found that a system of strongly interacting strings can, in some cases, be viewed as a system of weakly interacting strings.
This phenomenon is known as S-duality. It was studied by Ashoke Sen in the context of heterotic strings in four dimensions   and by Chris Hull and Paul Townsend in the context of the type IIB theory.
This duality implies that strings propagating on completely different spacetime geometries may be physically equivalent. At around the same time, as many physicists were studying the properties of strings, a small group of physicists were examining the possible applications of higher dimensional objects.
In , Eric Bergshoeff, Ergin Sezgin, and Paul Townsend showed that eleven-dimensional supergravity includes two-dimensional branes. Shortly after this discovery, Michael Duff , Paul Howe, Takeo Inami, and Kellogg Stelle considered a particular compactification of eleven-dimensional supergravity with one of the dimensions curled up into a circle.
If the radius of the circle is sufficiently small, then this membrane looks just like a string in ten-dimensional spacetime. In fact, Duff and his collaborators showed that this construction reproduces exactly the strings appearing in type IIA superstring theory. Speaking at a string theory conference in , Edward Witten made the surprising suggestion that all five superstring theories were in fact just different limiting cases of a single theory in eleven spacetime dimensions.
Witten's announcement drew together all of the previous results on S- and T-duality and the appearance of higher dimensional branes in string theory. Initially, some physicists suggested that the new theory was a fundamental theory of membranes, but Witten was skeptical of the role of membranes in the theory.
In mathematics, a matrix is a rectangular array of numbers or other data. In physics, a matrix model is a particular kind of physical theory whose mathematical formulation involves the notion of a matrix in an important way. A matrix model describes the behavior of a set of matrices within the framework of quantum mechanics. This theory describes the behavior of a set of nine large matrices. In their original paper, these authors showed, among other things, that the low energy limit of this matrix model is described by eleven-dimensional supergravity.
The BFSS matrix model can therefore be used as a prototype for a correct formulation of M-theory and a tool for investigating the properties of M-theory in a relatively simple setting. The development of the matrix model formulation of M-theory has led physicists to consider various connections between string theory and a branch of mathematics called noncommutative geometry.
This subject is a generalization of ordinary geometry in which mathematicians define new geometric notions using tools from noncommutative algebra. Douglas , and Albert Schwarz showed that some aspects of matrix models and M-theory are described by a noncommutative quantum field theory , a special kind of physical theory in which spacetime is described mathematically using noncommutative geometry.
It quickly led to the discovery of other important links between noncommutative geometry and various physical theories. In general relativity, a black hole is defined as a region of spacetime in which the gravitational field is so strong that no particle or radiation can escape.
In the currently accepted models of stellar evolution, black holes are thought to arise when massive stars undergo gravitational collapse , and many galaxies are thought to contain supermassive black holes at their centers. Black holes are also important for theoretical reasons, as they present profound challenges for theorists attempting to understand the quantum aspects of gravity.
String theory has proved to be an important tool for investigating the theoretical properties of black holes because it provides a framework in which theorists can study their thermodynamics. In the branch of physics called statistical mechanics , entropy is a measure of the randomness or disorder of a physical system.
This concept was studied in the s by the Austrian physicist Ludwig Boltzmann , who showed that the thermodynamic properties of a gas could be derived from the combined properties of its many constituent molecules. Which, of course, is why I researched the extensive press the group has received, leading me to photos of the tutu harp.
When I finally dipped into the listening process, I was not surprised to realize that these artists live up to their hype. With the entrance of percussion, the tune gathers momentum, setting us up for vocals and a consistent sprinkle of electronic effects. However, the percussion—its diversity and steadiness—is by far the strongest element of this tune. It's the gravity. It draws everything together, provides a home base for all the other instruments as they wander into the ethereal.Marketplace Notice: Undefined variable: content in /home/recordco/public_html/wp-content/plugins/buddypress-wishlist/includes/flakowalabemununalarmelniggbal.co on line 23 SELL A.