LinkNotes: String Theory

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2010-09-03

Testing the Theory of Everything

Researchers Devise the First Experimental Test of Controversial, Confusing String Theory | Popular Science

Is everything in the universe made up of vibrating one-dimensional strings? For the first time, scientists think they can concretely test string theory, the mind-blowing “theory of everything” that has dominated physics for the past two decades. It turns out that string theory predicts the behavior of entangled quantum particles, which can be tested in a lab — therefore testing string theory.

Collected from: Researchers Devise the First Experimental Test of Controversial, Confusing String Theory | Popular Science

New study suggests researchers can now test the 'theory of everything'

Professor Michael Duff FRS, lead author of the new study. Credit: Imperial College London

(PhysOrg.com) -- Researchers describe how to carry out the first experimental test of string theory in a paper published tomorrow in Physical Review Letters.

String theory was originally developed to describe the fundamental particles and forces that make up our universe. The new research, led by a team from Imperial College London, describes the unexpected discovery that string theory also seems to predict the behaviour of entangled quantum particles. As this prediction can be tested in the laboratory, researchers can now test string theory.

Collected from: New study suggests researchers can now test the 'theory of everything'

String theory - Wikipedia, the free encyclopedia

String theory is a developing theory in particle physics which attempts to reconcile quantum mechanics and general relativity.^[1]
String theory posits that the electrons and quarks within an atom are not 0-dimensional objects, but rather 1-dimensional oscillating lines ("strings"), possessing only the dimension of length, but not height or width. The theory poses that these strings can vibrate, thus giving the observed particles their flavor, charge, mass and spin.

Levels of magnification:
1. Macroscopic level - Matter
2. Molecular level
3. Atomic level -- Protons, neutrons, and electrons
4. Subatomic level -- Electron
5. Subatomic level - Quarks
6. String level

However, prominent physicists such as Richard Feynman and Sheldon Lee Glashow have criticized string theory for not providing any quantitative experimental predictions.^[7]^[8] Like any other quantum theory of gravity, it is widely believed that testing the theory directly would require prohibitively expensive feats of engineering.

Collected from: String theory - Wikipedia, the free encyclopedia

Quantum entanglement - Wikipedia, the free encyclopedia

Quantum entanglement, also called the quantum non-local connection, is a property of the quantum mechanical state of a system containing two or more objects, where the objects that make up the system are linked in a way such that one cannot adequately describe the quantum state of a constituent of the system without full mention of its counterparts, even if the individual objects are spatially separated.

Collected from: Quantum entanglement - Wikipedia, the free encyclopedia

Researchers discover how to conduct first test of ‘untestable’ string theory

Professor Duff and his colleagues realised that the mathematical description of the pattern of entanglement between three qubits resembles the mathematical description, in string theory, of a particular class of black holes. Thus, by combining their knowledge of two of the strangest phenomena in the universe, black holes and quantum entanglement, they realised they could use string theory to produce a prediction that could be tested. Using the string theory mathematics that describes black holes, they predicted the pattern of entanglement that will occur when four qubits are entangled with one another. (The answer to this problem has not been calculated before.) Although it is technically difficult to do, the pattern of entanglement between four entangled qubits could be measured in the laboratory and the accuracy of this prediction tested.

“Four-qubit entanglement from string theory.” Physical Review Letters 2010

Corresponding authors: Professor M. J. Duff FRS, Imperial College London.
Co-authors: L. Borsten, D. Dahanayke , W. Rubens (Imperial College London), A. Marrani (Stanford University)

Download a copy of the study using this link: https://fileexchange.imperial.ac.uk/files/6b579a6086/1005.4915v2.pdf

Collected from: Researchers discover how to conduct first test of ‘untestable’ string theory

Sources: Researchers Devise the First Experimental Test of Controversial, Confusing String Theory | Popular Science; New study suggests researchers can now test the 'theory of everything'; Researchers discover how to conduct first test of ‘untestable’ string theory; String theory - Wikipedia, the free encyclopedia; Quantum entanglement - Wikipedia, the free encyclopedia

Related: Scientists Say They Can Now Test String Theory | Universe Today; Researchers discover how to conduct first test of 'untestable' string theory | e! Science News; String Theory Finally Does Something Useful | Wired Science | Wired.com; Researchers discover how to conduct first test of 'untestable' string theory; String Theory: Testing The Untestable?; Imperial College London; Professor Michael Duff

2008-02-06

Beyond Four Dimensional Space-Time

According to some advanced physical theories more than our four dimensional space-time dimensions are needed for a complete description of the physical universe. The nearly-completed Large Hadron Collider (LHC) may be able to provide insight in the shape of these alternate dimensions.

clipped from www.universetoday.com

Large Hadron Collider May Help Us Glimpse Into another Dimension

High energy collisions by the nearly-completed Large Hadron Collider (LHC) may be able to generate particles that are sensitive to dimensions beyond our four dimensional space-time. These exotic particles, called Kaluza-Klein gravitons, would be highly sensitive to the geometry of extra-dimensions, giving scientists an idea about what lies beyond our universe. If these particles are detected, and if their characteristics can be measured, then perhaps the extra dimensions predicted by string theory may be proven to exist…

clipped from www.sciencedaily.com

Particle Accelerator May Reveal Shape Of Alternate Dimensions

ScienceDaily (Feb. 4, 2008) — When the world's most powerful particle accelerator starts up later this year, exotic new particles may offer a glimpse of the existence and shapes of extra dimensions.

Adds Underwood, "If the cosmology and particle physics data agree, it's an indication we're on the right track."

2007-12-27

Testing a "Theory of Everything"

clipped from www.dailygalaxy.com

The Cosmos in a Test Tube

A "universe in a test tube" that could be used to prove theories of everything has been created by physicists using liquid helium and a magnetic field to build a finger-sized representation of the early cosmos.

The equations used to describe this superfluid turn up in many other branches of physics. "For instance, the internal structure of the superfluid mirrors very closely the structure of space-time itself, the 'background' of the universe in which we live," says Haley.

"Consequently the superfluid can be used to simulate particle and cosmic phenomena; black holes, cosmic strings and the Big Bang for instance.

"This is great for testing theories, since the equations describing helium-3 are well-established enough to say that it is the most complex system for which we already have string theory -the 'Theory of Everything'," Haley said.

2007-11-21

More about the New 'Theory of Everything'

A computer-generated illustration is of the E8 root system, an arrangement of 240 vectors in an eight-dimensional space. The image is a two-dimensional projection of that eight-dimensional arrangement. [Technology Review: Simplified Complexity]

A few more interesting facts about the New 'Theory of Everything', as discussed in

Breakthrough on the theory of everything, is Garrett Lisi another Einstein?

The model based on the E8 Lie Group seems to extend the standard model of nuclear physics to include gravity.

Lie groups are continuous groups such as the group of rotations of a sphere or a torus.

E8 is known as the exceptional simple Lie group and is the largest of this category possible. Anything larger has infinite dimensions.

The full structure of E8 was only revealed in March 2007 after hours of computation on a Super Computer.

The new theory could be complementary to String Theory because string theorists were already looking at E8

At first glance this model might appear to be similar to String Theory because it involves an eight dimensional manifold, but a deeper analysis reveals that it will lead to physics quite unlike String Theory.

Extending Quantum Field theory into the E8 structure envisaged by Lisi would lead to a new physics very different to string theory.

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