Why space has exactly three dimensions - physics-math - 26 September 2013 - New Scientist

Why space has exactly three dimensions - physics-math - 26 September 2013 - New Scientist: Quantum states are described not by 1D real numbers, which all lie on a single line, but by 2D complex numbers that represent points on a plane. The way these numbers interact to produce a complete description of objects such as photons that can be in more than one state at once naturally sketches out a 3D sphere describing all those possible states. Perhaps this result is just emphasising how the dimensionality of basic quantum objects and the dimensionality of space happen to be the same.

Müller thinks not: he thinks it points to an inextricable link between space's geometry and the degree of probability inherent in quantum theory. If so, the roots of relativity and quantum theory would be embedded in the way information is exchanged in the cosmos, suggesting where to look for any unifying theories. "It offers a clue that the notion of information will be an important part of quantum gravity," says Müller.

Physicists Discover Geometry Underlying Particle Physics | Simons Foundation

Physicists Discover Geometry Underlying Particle Physics | Simons Foundation: The amplituhedron looks like an intricate, multifaceted jewel in higher dimensions. Encoded in its volume are the most basic features of reality that can be calculated, “scattering amplitudes,” which represent the likelihood that a certain set of particles will turn into certain other particles upon colliding.

Did a hyper-black hole spawn the Universe? : Nature News & Comment

Did a hyper-black hole spawn the Universe? : Nature News : ...in the bulk universe the event horizon of a 4D black hole would be a 3D object — a shape called a hypersphere. When Afshordi’s team modeled the death of a 4D star, they found that the ejected material would form a 3D brane surrounding that 3D event horizon, and slowly expand.


The authors postulate that the 3D Universe we live in might be just such a brane — and that we detect the brane’s growth as cosmic expansion. “Astronomers measured that expansion and extrapolated back that the Universe must have begun with a Big Bang — but that is just a mirage,” says Afshordi.

The model also naturally explains our Universe’s uniformity...

'Holographic Duality' Hints at Hidden Subatomic World - Wired Science

'Holographic Duality' Hints at Hidden Subatomic World - Wired Science; If strongly correlated matter is thought of as “living” on the 2-D surface of a pond, the holographic duality suggests that the extreme turbulence on that surface is mathematically equivalent to still waters in the interior. Physicists can get at the surface-level behavior by studying the parallel, but much simpler, situation below...

In the mathematical parlance of the holographic duality, certain strongly correlated matter in 2-D corresponds, in 3-D, to a black hole.... “These very complicated quantum mechanical collective effects are beautifully captured by black hole physics... For strongly correlated systems, if you put an electron into the system, it will immediately ‘disappear’ — you can no longer track it.” It’s like an object falling into a black hole.


To determine a formula for the conductivity of cuprates, Horowitz and Santos had to study how light would interact with the complicated horizon of their black hole... In the new work, they extended the calculation down to the temperature range in which cuprates become superconductive, or conduct electricity with no resistance, and again found a close match with experimental measurements of real cuprates.

Solved? 80-year-old puzzle of the infinite sphere

Solved? 80-year-old puzzle of the infinite sphere: Would a basketball spinning on a fingertip behave the same way in an infinite number of dimensions? The question has flummoxed mathematicians for 80 years, but now it looks as if the answer is yes – a find that could have implications for quantum theory.

String theorists squeeze nine dimensions into three

String theorists squeeze nine dimensions into three: In the simulation, the universe starts off as a tiny blob of strings that is symmetric in nine different dimensions. As the strings interact, a random energy fluctuation — provided by the quantum laws that govern these small scales — breaks the symmetry. Three dimensions balloon outward, leaving the other six stunted at a billionth of a trillionth of a trillionth of a centimeter, far too small to be detected.

Naked black-hole hearts live in the fifth dimension

Naked black-hole hearts live in the fifth dimension: Lehner has now proposed another situation where naked singularities might exist: in the extra dimensions proposed by string theory. The rub is that this time, they aren't unusual.

To understand why, think of black holes as points in the four dimensions we experience - three of space and one of time. These become "black strings" when extended into a fifth dimension of space (see diagram).

Black strings are unstable and break up into smaller black holes like a stream of water splitting into droplets. Lehner showed that at the point where a smaller black hole pinches off from the stream, the black hole's radius is zero, which means its density is infinite. In other words, it is a naked singularity. Lehner showed this will happen any time you have a black string.

Could a planet have only one pole?

Could a planet have only one pole?: You are on Boy's Surface, discovered by Werner Boy in 1901, and represented as a strange planet by John Pierre Petit in his book, Le Topologicon, in 1902. Each of the 'wings' can be traced by a Mobius Strip. The planet is a four dimensional object that penetrates itself without causing any holes or edges.

What if there is no Higgs boson?

What if there is no Higgs boson?:  Physicists are only looking for the Higgs particle because it is the easiest way to access the field. If they don't see it, then it suggests the field is different from the one predicted by the standard model. Normally, particles in fields are like ripples in ponds – photons are ripples in the electromagnetic field, for example. But if the field is more like molasses than water, then the ripples die away too quickly for us to detect.

That means matter might get its mass from a thick Higgs-like field that has no associated particle. To get such a goopy field, theorists need to add in more exotic possibilities – such as new particles or forces of nature...

The existence of a new force, called technicolour, could also give particles mass without the need for a Higgs boson. Technicolour would act like a heavy-duty version of the strong nuclear force, which binds quarks together in the nuclei of atoms. The technicolour force would fill space with pairs of still more new particles, which would form a soup through which other particles would travel, gaining mass in the process....

The existence of a fourth dimension of space, beyond the three we experience, could explain why particles have different masses – a fact that is usually attributed to the Higgs boson.

One weird theory could make anti-gravity and faster-than-light travel possible

One weird theory could make anti-gravity and faster-than-light travel possible: Heim Theory was originated by Burkhard Heim, a German physicist, in the mid-twentieth century. It was attempted as a way to reconcile the two pillars of physics, quantum theory and general relativity. It takes what's currently the only way out, between the two theories - extra dimensions...
Heim's goal was to find ways to convert between all kinds of energy, and in adding two dimensions to his calculations he was able to equate, at least in theory, gravitational energy and electromagnetism.

Black holes and pulsars could reveal extra dimensions - space - 21 August 2011 - New Scientist

Black holes and pulsars could reveal extra dimensions: Black holes are predicted to fritter away their mass over time by emitting particles, a phenomenon called Hawking radiation. Without extra dimensions, this process is predicted to be agonisingly slow for run-of-the-mill black holes weighing a few times as much as the sun, making it impossible to measure.

Extra dimensions would give the particles more ways to escape, speeding up the process.

Hologram revolution: The theory changing all physics - physics-math - 13 July 2011 - New Scientist

Hologram revolution: The theory changing all physics: Leonard Susskind of Stanford University in California, one of the original architects of the holographic principle, describes the duality as the "new orthodoxy". Skenderis is convinced that we are only just beginning to see its potential. "If we look forward to 50 years from now, we will see this period as a precursor to a time when physics is totally reformulated in the language of holography," he says. "Once the theory is properly fleshed out, we will be able to apply it to almost any problem."

Exotic sphere discoverer wins mathematical 'Nobel' - physics-math - 23 March 2011 - New Scientist

Exotic sphere discoverer wins mathematical 'Nobel': Imagine splitting an ordinary sphere into two halves along the middle, so that each half has a copy of every point on the equator. Now rejoin the two halves so that the southern copy of a point doesn't join its northern counterpoint. In two dimensions, there's only one way to do this: by twisting the sphere. But in seven dimensions the points can be mixed up with respect to each other in multiple different ways...
It turns out there are a total of 28 exotic spheres in seven dimensions, and they also exist in other dimensions. Dimension 15 has as many as 16,256, while others like dimensions five and six only have the ordinary sphere. Mathematicians don't yet know whether exotic spheres exist in four dimensions – a problem known as the smooth Poincaré conjecture, and related to the generalised Poincaré conjecture, which was solved in 2003.

Physicists investigate lower dimensions of the universe

Physicists investigate lower dimensions of the universe: So far, there may already be one piece of experimental evidence for the existence of a lower-dimensional structure at a higher energy scale. When observing families of cosmic ray particles in space, scientists found that, at energies higher than 1 TeV, the main energy fluxes appear to align in a two-dimensional plane. This means that, above a certain energy level, particles propagate in two dimensions rather than three dimensions.

In the current study, Mureika and Stojkovic have proposed a second test for lower dimensions that would provide independent evidence for their existence. The test is based on the assumption that a (2 + 1)-dimensional spacetime, which is a flat plane, has no gravitational degrees of freedom. This means that gravity waves and gravitons cannot have been produced during this epoch. So the physicists suggest that a future gravitational wave detector looking deep into space might find that primordial gravity waves cannot be produced beyond a certain frequency, and this frequency would represent the transition between dimensions. Looking backwards, it would appear that one of our spatial dimensions has “vanished.”
The scientists added that it should be possible, though perhaps more difficult, to test for the existence of (1 + 1)-dimensional spacetime.

Topologist Predicts New Form of Matter� - Technology Review

Topologist Predicts New Form of Matter� - Technology Review: "And topology is about to extend its influence, if Baas has his way. He points out that Borromean rings are just the simplest example of an entire periodic table of topological structures. And if it's possible to make Efimov states that are equivalent to Borromean rings, then it ought to be possible to make the others too.

This family of stuff will be a new state of matter that is governed by news rules, a kind of 'Efimov physics'.

How might this stuff behave? That isn't yet clear but Baas raises an interesting possibility. The deep and unworldly link between particles in Efimov states is remarkably similar to quantum entanglement."

Gravity up close: Looking for extra dimensions by measuring gravity at the microscopic level

Gravity up close: Looking for extra dimensions by measuring gravity at the microscopic level: "A new detection apparatus proposed by the National Institute of Standards and Technology in Boulder, Colo., hopes to explore gravity at the 100-1,000 nanometer level -- larger than atoms but many thousands of times smaller than any previous experiment has achieved. They hope to measure gravity over the shortest range yet.
Their apparatus consists of a tiny glass bead suspended in vacuum by laser beams. A gold rod is swept past the bead, disturbing its place in the laser beams. The bead then oscillates back and forth, and this pendulum-like motion provides a way to precisely measure the force of gravity between the rod and the bead."

Beyond space and time: Fractals, hyperspace and more

http://www.newscientist.com/special/beyond-space-and-time

Hypersphere Exotica: Kervaire Invariant Problem Has a Solution!

http://www.scientificamerican.com/article.cfm?id=hypersphere-exotica

Shadow world

How many dimensions space has could all be a matter of perspective

http://www.sciencenews.org/view/feature/id/9115/title/Shadow_World

Mapping the 248-Fold Way

The Atlas Project to map the structure E8

http://www.sciencemag.org/cgi/content/summary/315/5819/1647