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RE: Theory of Everything
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Is mathematical pattern the theory of everything?
Garrett Lisi is an unlikely individual to be staking a claim for a theory of everything. He has no university affiliation and spends most of the year surfing in Hawaii. In winter, he heads to the mountains near Lake Tahoe, California, to teach snowboarding. Until recently, physics was not much more than a hobby.
That hasn't stopped some leading physicists sitting up and taking notice after Lisi made his theory public on the physics pre-print archive this week (www.arxiv.org/abs/0711.0770). By analysing the most elegant and intricate pattern known to mathematics, Lisi has uncovered a relationship underlying all the universe's particles and forces, including gravity - or so he hopes. Lee Smolin at the Perimeter Institute for Theoretical Physics (PI) in Waterloo, Ontario, Canada, describes Lisi's work as "fabulous".

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A sophisticated, new analysis has revealed that the next frontier in particle physics is farther away than once thought. New forms of matter not predicted by the Standard Model of particle physics are most likely twice as massive as theorists had previously calculated. The result comes from a just-published study that was featured on the cover of Physical Review Letters.
To see the infinitely small bits of matter that make up our universe, physicists build ever more powerful accelerators, the microscopes they use to see matter. But while the trend is to more powerful accelerators, the precision achieved by some less powerful ones can pinpoint the best places to look for never-before-seen particles. It turns out that high-precision measurements can reveal the signature of new forms of matter.
In a recent study, Jefferson Lab scientists combined data from two Jefferson Lab experiment groups, G-Zero and HAPPEx, and from the PVA4 collaboration at Mainz and SAMPLE at MIT-Bates. These groups conducted experiments in which electrons were used to precisely probe the nucleus of the atom.
The experiments studied the weak nuclear force, one of the four forces of nature. Using the experimental data from all of these groups, Jefferson Lab researchers precisely determined the effects of the weak force on the building blocks of the proton, up and down quarks.
Moreover, when this new analysis was combined with still other measurements, it raised the predicted mass scale for the discovery of new particles to about one Tera-electron-volts (1 TeV) more than a factor of two higher than previously thought. The discovery is noteworthy, because experimental improvements of this magnitude rarely occur more often than once in a decade.
The result also shows one possible impact of data from the upcoming Q-weak experiment in Jefferson Lab's Hall C. It shows that, with Q-weak's anticipated accuracy, the experiment will improve the current analysis's measurement of the effects of the weak force on up and down quarks by a factor of five. It could also raise the predicted mass for new particles another 1 TeV.

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Finding evidence to back up a theory of everything was always going to be difficult. Now two particle physicists say they may have tracked some down - lurking inside black holes.
The pair's calculations have revealed that black holes might be harbouring enigmatic hypothetical entities called magnetic monopoles. If they are, not only would physicists have stumbled upon a key ingredient for a theory of everything, but it may explain why some black holes rotate.
Physicist Paul Dirac first proposed magnetic monopoles in 1931. Unlike magnetic poles, which come in north and south pairs, monopoles carry just a single magnetic "charge". Dirac proposed that monopoles are necessary to explain why electrons carry just a single electric charge.

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Early String Theory research and the anomalies that led to the introduction of M-theory, the next possible "Theory Of Everything", an excerpt from NOVA's Elegant Universe



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Planck Mass
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Title: What is Special About the Planck Mass?
Authors: C. Sivaram (1) ((1) Indian Institute of Astrophysics)

Planck introduced his famous units of mass, length and time a hundred years ago. The many interesting facets of the Planck mass and length are explored. The Planck mass ubiquitously occurs in astrophysics, cosmology, quantum gravity, string theory, etc. Current aspects of its implications for unification of fundamental interactions, energy dependence of coupling constants, dark energy, etc. are discussed.

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Planck Length
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Title: Planck Length and Cosmology
Authors: Xavier Calmet

We show that an unification of quantum mechanics and general relativity implies that there is a fundamental length in Nature in the sense that no operational procedure would be able to measure distances shorter than the Planck length. Furthermore we give an explicit realisation of an old proposal by Anderson and Finkelstein who argued that a fundamental length in nature implies unimodular gravity. Finally, using hand waving arguments we show that a minimal length might be related to the cosmological constant which, if this scenario is realised, is time dependent.

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RE: Theory of Everything
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Title: Gamow Legacy and the Primordial Abundance of Light Elements
Authors: E. Terlevich (INAOE), R. Terlevich (INAOE), V. Luridiana (IAA-CSIC)

The presently accepted "Theory of the Universe" was pioneered 60 years ago by Gamow, Alpher and Herman. As a consequence of the, later dubbed, Hot Big-Bang, matter was neutrons, and after some decay protons, and a history of successive captures built up the elements. It wasn't until some 15 years later (with the discovery of the Cosmic Microwave Background radiation) that Gamow and colleagues theories were validated and present day Standard Big-bang Nucleosynthesis theory was developed. We will discuss the importance of state of the art observations and modelling in the quest to determine precise values of the primordial abundance of D and 4He, using observations of astrophysical objects and modern day atomic parameters. In particular, we will present the search for understanding and coping with systematic errors in such determinations.

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The Big Questions: Is the universe deterministic?
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New Scientist tackles eight of the deepest challenges faced by science - from reality and consciousness, to free will and death, in The Big Questions special features.

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Gravity
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Title: A Lower Limit to the Scale of an Effective Theory of Gravitation
Authors: R. R. Caldwell, Daniel Grin

Researchers consider a linearised, effective quantum theory of gravitation which is cut off at a low energy scale in order to accommodate the smallness of the cosmological constant.
This theory predicts departures from the static Newtonian inverse-square force law on distances below ~0.05 mm. However, they show that such a cutoff also leads to changes in the long-range behaviour of gravity, and is inconsistent with observed gravitational lenses.

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GRAVITY IS NORMAL DOWN TO THE 100-nm LEVEL.

Gravity at the level of planets is well studied, and was known accurately even in Newton's day. This is owing to the fact that the other physical forces, such as the strong and weak nuclear forces, don't operate over such great distances, and electromagnetic forces between immense far-apart, electrically-neutral objects like planets are dilute.
Gravity at shorter lengths, by contrast, is harder to measure, partly because all the other forces are in full play.
Furthermore, theories of particle interactions hypothesizing the existence of additional spatial dimensions suggest that the strength of gravity will depart from Newton's famous inverse-square formulation.
To test these propositions, various tabletop setups have been devised to probe gravity below the micron level.
One previous experiment, conducted by Eric Adelberger's group at the University of Washington, ruled out extra gravity components having strength comparable to conventional gravity down to a size scale of about 100 microns .

A new experiment, carried out by a Indiana/Purdue/Lucent/Florida/Wabash collaboration examines a shorter distance scale-100 nm - but is able to rule out
only corrections to gravity that are, in fact, a trillion times larger than gravity itself. Nevertheless, such measurements help to constrain the general pursuit of unified theories of particle physics, including explanations of gravity.

The sort of "Yukawa" corrections being sought are analogous to the force proposed by Hideki Yukawa in the 1930s to explain how mesons transmit the nuclear force between nucleons and would come about because of transmission of the presumed force particles associated with the hypothetical extra dimensions. The present measurements improve the
exclusion of such corrections by a factor of ten. According to Ricardo Decca of Indiana University-Purdue University, the sensitivity of the apparatus should grow by a factor of a hundred over the next year. The size of the sample is smaller here than in many other tabletop gravity experiments.

The flea-sized torsional apparatus must operate with such concern for forces acting over small distances that one of the chief goals here is reducing the background produced by the Casimir force - a quantum effect in which two very close objects are drawn together because of the way they exclude vacuum fluctuations (that is, the
spontaneous creation of pairs of virtual particles) from occurring in a slender volume of space - between a flat plane and sphere lying only 200 nm apart.


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