In search of extra dimensions: Hang on -- a new reality may be around the corner

spaceref.com ^ | 19 Feb 02 | Press Release

[RightWhale]

http://www.spaceref.com/news/viewpr.html?pid=7456

PRESS RELEASE

Date Released: Monday, February 18, 2002

American Association for the Advancement of Science

In search of extra dimensions: Hang on -- a new reality may be around the corner

BOSTON, MASS. -- "Reality is merely an illusion, albeit a persistent one," according to the late Albert Einstein. But, "if everything is an illusion and nothing exists," humorist Woody Allen has observed, "I definitely overpaid for my carpet."

Hang onto your carpet receipts:

Our understanding of reality -- that is, a world where events happen over time within a three-dimensional space -- may be turned on its head by the year 2005, scientist Maria Spiropulu said today during the American Association for the Advancement of Science (AAAS) Annual Meeting.

"The way we think about things is about to change completely," said Spiropulu. "This is truly a revolution in the way we understand our world."

Spiropulu, a 32-year-old scientist with the Enrico Fermi Institute at the University of Chicago, is hot on the trail of extra dimensions. She's using new methods to prove, experimentally, whether our reality is more complicated than we previously assumed.

"We are very close" to a new reality, she said. "Right now, we imagine space and time as a static question, and we solve equations as a function of space and time. But, what we're learning is that, at the very large scale or the very small scale, space and time are dynamic. What is happening at those scales, we cannot explain. So we have to wonder, do these scales hold some extra dimensions?"

Traditionally, physicists have mathematically explained all that happens in the world by using a "standard model." In this system, all matter is made of lightweight "leptons" (such as electrons and neutrinos) and quarks. Three forces manipulate these particles: electromagnetism, and strong and weak nuclear reactions.

But, this traditional approach doesn't explain gravity, the fourth force. The conventional rules of quantum mechanics have been successfully married with Einstein's Theory of Special Relativity, which explains the behavior of very fast objects -- but not with his Theory of General Relativity, the guidebook to gravitational force. Mathematical gobbledygook usually results from trying to combine quantum mechanics and general relativity. Consequently, we still don't know, for example, what happens to particles sucked into a black hole.

In an effort to uniformly explain all events, physicist Gunnar Nordstrom (1881-1923) first introduced the notion of an extra dimension at the beginning of the 20th century. Perhaps, he thought, gravity happens in a realm we don't understand and can't mathematically define. Some 10 years later, Theodor Kaluza (1885-1954) and Oskar Klein (1894-1977) took Nordstrom's ideas another step forward: An extra dimension may be curled up like an unimaginably small ball, they said, on the order of the Planck scale -- the smallest unit of length in the universe (10 to the minus 33 centimeters).

The idea of an extra dimension was resurrected yet again in the late 1990s, as scientists began to ask whether Newton's Law of Universal Gravitation reliably predicts gravity's behavior below the centimeter scale, Spiropulu explained. Physicists were energized in 1997 by the discovery of possible links between the standard model and "superstring theory" -- the notion that a series of extremely tiny, vibrating strings may lurk beneath the level of quarks and leptons.

Researchers Nima Arkani-Hamed, Savas Dimopoulos, and Gia Dvali then caused further excitement, by suggesting that at least one of these tiny dimensions might, in fact, be large enough to measure. Still, no one has produced undeniable proof of superstrings, and many questions persist.

Since then, Spiropulu reported to AAAS attendees, experiments have shown that Newton's Law is valid down to the 200-micron level. That is, gravity "follows the rules" at that scale. But, the physical reality below this level remains a mystery. Somewhere within the Planck scale, or at extreme energy levels, an incredibly small extra dimension may finally combine gravity and electromagnetism, Spiropulu suggested.

"We're very close into the energies where we can see effects of a very low-energy Planck scale," she said. "If an extra dimension is mirroring the Planck Scale, that means that gravity and the electromagnetic theory is going to be unified tomorrow."

Gravity, Spiropulu said, may soon be unified in an "unexplainable hierarchy of scale."

Various scenarios or "frameworks" are emerging to describe a mysterious sister world where, as Alice in Wonderland once remarked, "nothing would be what rings, because everything would be what it isn't."

Our three-dimensional world includes the coordinates X, Y, and Z, extending infinitely throughout the universe. But, some researchers have proposed that extra dimensions may be finite, and compacted around a sphere, pole, or other geometrical shape. Others have said that quarks, the standard-model particles, may have "technicolor" cousins in another realm. Or, quarks and neutrinos may exist in a mirror-world, as "squarks" and "sneutrinos."

To learn more about what's happening at the very small scale, Spiropulu and her colleagues are staging high-energy particle collisions. Extra dimensions, she explained, would leave behind a "signature," and she hopes to detect it. The classic signature might be a graviton -- the carrier of gravity -- capable, perhaps, of trickling to another dimension. In her experiments, protons (the hydrogen nucleus is a proton) going at almost the speed of light smash head-on into anti-protons. "What comes out," she said, "is a graviton, escaping into an extra dimension, and leaving a viable signature in your detector."

In particle collisions, the conservation of energy and momentum can be measured, so that what goes into the initial experiment must jive with what's left over, post crash-test. "If it doesn't add up and you have significant imbalance," she explained, "that is a viable signal that there is an extra dimension where, if these theories are valid, gravity may become very strong, and other weird properties might kick in. The idea is that there may be a form of super-gravity in the extra dimension."

Spiropulu shared the latest experimental findings at the AAAS meeting, including a completely new -- and what she described as "totally innovative strategy" -- worked out by Harvard's Nima Arkani-Hamed and others for "dynamically generating an extra dimension and then testing it," rather than the opposite, more conventional strategy: Searching for proof of an assumed extra dimension.

"We're looking at some really neat, new ideas," she concluded. "We hope by 2005 to have great results on this topic."

[Savage Beast]

Once on a solo camping trip in Canyonlands National Park in Utah, alone in the gorgeous solitude, I was musing on the faces and maps etc. in the clouds. I knew, of course, that they were not real faces etc. and that they were illusions, projections of my mind onto the clouds.

Then I began to see faces etc. in the distant rocks, just like the clouds. These too, of course, were illusions, projections of what was in my mind.

Then I began to realize that the clouds themselves were projections of my mind, just as illusory as the faces--

And the distant rocks were also projections.

Then I realized that everything, the entire world around me, was projected from my mind onto a flowing energy field--

And that the energy field itself was a projection.

Then I realized that the only thing that is absolutely real, about me or the world around me, is God.

Later I discovered this concept in ancient (and modern) Hindu/Buddahist philosophy--the concept of the maya.

This is consistent with Christian beliefs.

Inasmuch as Jesus Christ is my only Mediator, Advocate, and Guide, and the only One to Whom I will entrust my immortal soul, I am a Christian.

This is my paradigm. It works for me. If it doesn't work for anyone else, so what? We all live in our own unique paradigms--or “frameworks” of illusions--and everybody else's paradigm is as illusory as mine is anyway.

[vannrox]

A very interesting person. Go HERE and go through one of his classes. A very interesting subject.

[Senator Pardek]

Is that where Stella got her groove back?

[vannrox]

[scouse]

This isn't a new idea. In the old Superman comics; Superman had a nemesis who went by the name of Mr Xptfpl(sp). He was from another dimension and Superman used to trick him into returning to his home dimension by causing him to repeat his name backwards.
Never ever say your name backwards.....:^))

[vannrox]

Fermilab Library Presents:
Selected Bibliographies of Fermilab Colloquia Speakers

Nima Arkani-Hamed

Author(s): Arkani-Hamed, Nima; Cohen, Andrew G; Georgi, Howard
Title: Anomalies on orbifolds
Source: Physics letters: B. 516, no. 3, (2001): 395 (8 pages) Author(s): Arkani-Hamed, Nima; Cohen, Andrew G; Georgi, Howard
Title: Electroweak symmetry breaking from dimensional deconstruction
Source: Physics letters: B. 513, no. 1, (2001): 232 (9 pages)

Author(s): Arkani-Hamed, Nima; Hall, Lawrence; Nomura, Yasunori, and others
Title: Finite radiative electroweak symmetry breaking from the bulk
Source: Nuclear physics. B. 605, no. 1, (2001): 81 (35 pages)

Author(s): Arkani-Hamed, Nima; Cohen, Andrew G; Georgi, Howard
Title: Elementary Particles and Fields - (De)Constructing Dimensions
Source: Physical review letters. 86, no. 21, (2001): 4757 (5 pages)

Author(s): Arkani-Hamed, Nima; Dimopoulos, Savas; March-Russell, John
Title: Stabilization of submillimeter dimensions: The new guise of the hierarchy problem
Source: Physical review. D, Particles and fields. 63, no. 6, (2001): 64020 (1 pages)

Author(s): Arkani-Hamed, Nima; Hall, Lawrence; Smith, David, and others
Title: Exponentially small supersymmetry breaking from extra dimensions
Source: Physical review. D, Particles and fields. 63, no. 5, (2001): 56003 (1 pages)

Author(s): Arkani-Hamed, Nima; Hall, Lawrence J.; Kolda, Christopher, and others.
Title: Gravitation and Astrophysics - New Perspective on Cosmic Coincidence Problems
Source: Physical Review Letters. 85, no. 21, (2000):4434 (4 pages)

Author(s): Arkani-Hamed, Nima; Hall, Lawrence; Smith, David and others.
Title: Solving the hierarchy problem with exponentially large dimensions.
Source: Physical Review D. 62, no. 9, (2000): 96006 (1 page)

Author(s): Arkani-Hamed, Nima; Savas, Dimopoulos; Georgi Dvali
Title: The Universe's unseen dimensions
Source: Scientific American v.283 no2 (Aug. 2000) p. 62-9.

Author(s): Arkani-Hamed, Nima; Lawrence Hall; David Smith; Neal Weiner
Title: Flavor at the TeV scale with extra dimensions
Source: Phys. Rev. D v.61 no.11 (2000) p. 116003.

Author(s): Arkani-Hamed, Nima; Yuval Grossman; Martin Schmaltz
Title: Split fermions in extra dimensions and exponentially small cross sections at future colliders
Source: Phys. Rev. D v.61 no.11 (2000) p. 115004 .

Author(s): Arkani-Hamed, Nima; S. Dimopoulos; N. Kaloper; J. March-Russell
Title: Rapid asymmetric inflation and early cosmology in theories with sub-millimeter dimensions
Source: Nucl. Phys. B v.567 no.1 (2000) p. 189.

Author(s): Arkani-Hamed, Nima; Martin Schmaltz
Title: Hierarchies without symmetries from extra dimensions
Source: Phys. Rev. D v.61 no.3 (2000) p. 33005.

Author(s): Arkani-Hamed, Nima; Savas Dimopoulos; Gia Dvali; Nemanja Kaloper
Title: Elementary particles and fields - Infinitely large new dimensions
Source: Phys. Rev. Lett. v.84 no.4 (2000) p. 586.

Author(s): Arkani-Hamed, N.; S. Dimopoulos; R. Sundrum
Title: A Small cosmological constant from a large extra dimension
Source: Phys. Lett. B v.480 no.1-2 (May 4, 2000) p. 193.

Author(s): Arkani-Hamed, Nima; Savas Dimopoulos; Gia Dvali
Title: ARTICLES - Phenomenology, astrophysics, and cosmology of theories with submillimeter dimensions and TeV scale quantum gravity
Source: Phys. Rev. D v. 59 no.8 (1999) p. 86004.

Author(s): Arkani-Hamed, Nima; S. Dimopoulos; N. Kaloper; J. March-Russell
Title: Early inflation and cosmology in theories with sub-millimeter dimensions
Source: AIP conference proceedings no.478 (1999) p. 237-243.

Author(s): Arkani-Hamed, Nima
Title: Larger new dimensions and quantum gravity around the corner (Video)
Source: University of California, Berkeley; Department of Physics, 1999.

Author(s): Arkani-Hamed, Nima
Title: New sub-millimeter dimensions and quantum gravity around the corner (Video)
Source: University of California, Berkeley, Department of Physics, 1999.

Author(s): Antoniadis, Ignatios; Nima Arkani-Hamed; Savas Dimopoulos; Gia Dvali
Title: New dimensions at a millimeter to a fermi and superstrings at a TeV
Source: Phys. Lett. B v.436 no.3 (1998) p. 257.

Author(s): Arkani-Hamed, Nima; Savas Dimopoulos; Gia Dvali
Title: The hierarchy problem and new dimensions at a millimeter
Source: Phys. Lett. B v. 429 no.3-4 (1998) p. 263.

Author(s): Arkani-Hamed, Nima
Title: Supersymmetry and hierarchies (Ph.D Thesis)
Source: University of California, Berkeley, May 1997.

Go to the Fermilab Colloquia Homepage

[realpatriot71]

Thats an interesting way to look at things.

[vannrox]

Gravity in Large Extra Dimensions

In 1998, Nima Arkani-Hamed found himself pondering one of the conundrums of modern physics: why is gravity so much weaker than the other fundamental forces?


Surrounded by massive objects like falling apples, orbiting moons, and our own occasionally clumsy bodies, we don't think of gravity as weak. Compared to electromagnetism, however-or the aptly named strong force that binds quarks, or even the "weak" force that governs some forms of radioactive decay-gravity is feeble. A pin on a tabletop is held down by the gravity of the entire Earth; a toy magnet snaps it up.





An aerialist on a tight wire can travel in only one dimension, forward and back. A flea on the wire finds a "rolled-up" second dimension.


Particle accelerators have shown that electromagnetism and the weak force are aspects of one electroweak force; they will soon attain enough energy to observe "grand unification" with the strong force. Gravity too is unified with these forces, but because it is weaker by scores of orders of magnitude, accelerators can never achieve the colossal energies needed to see its unification-unless Nima Arkani-Hamed is right.


With his colleagues Savas Dimopoulos of Stanford and Gia Dvali of New York University, Arkani-Hamed, now of UC Berkeley and Berkeley Lab's Physics Division, proposed that gravity may function in more than three spatial dimensions. If so, we experience only part of its effect.


In a three-dimensional world, the strength of attraction is squared when the distance between two masses is halved (by the inverse-square law we learned in school). In four dimensions, however, strength varies as the cube, in five dimensions as the fourth power, and so on. Maybe gravity isn't weak at all; maybe it only seems that way.


How big would extra dimensions have to be? For gravity to equal the other forces at a hundred-thousandth of a trillionth of an inch (the electroweak scale), one extra dimension would have to be as big as the distance between the Earth and the sun. Two extra dimensions need extend only about a millimeter, however, and the more extra dimensions there are, the smaller they can be.


Additional dimensions are surprisingly easy to overlook. Consider a performer on a high wire, confined to a single dimension, forward and back. A flea can move around the wire as well as along it, experiencing an extra dimension.


Dimensions tinier than subatomic particles, like those invoked by superstring theory, would be impossibly hard to probe. On the other hand, with a single extra dimension of astronomical size, gravity would have collapsed the solar system. Between these extremes falls the millimeter scale.


Curiously, gravity has yet to be measured at much less than a millimeter. To calculate the gravitational attraction between two masses, one of them must be smaller than the distance separating them-easy with falling apples and orbiting moons but impossible with, say, poppy seeds.


Moreover, "as test masses get smaller, residual electromagnetic effects come into play and swamp gravitation," says Arkani-Hamed. "Nobody knows what the real force of gravity is at short distances."


That situation may soon change. Clever tabletop experiments test gravity at ever shorter distances. If they should observe a sudden startling increase in its strength at short distances, extra dimensions are the logical suspect.


Even more dramatic effects could be produced in particle accelerators such as the Large Hadron Collider now under construction in Europe. If some of the particles that carry gravity escape into extra dimensions, high-energy collisions would show a mass-energy deficit, apparently violating the first law of thermodynamics. Conversely, regions of immensely strong gravity might be created at short range-miniature black holes that quickly evaporate, releasing a shower of radiation "from nowhere."


Indeed, if our three-dimensional universe resides on a "wall" in a larger "bulk" of multiple dimensions, our world might be just one of many worlds, or it might be folded upon itself many times. Distant reaches of the cosmos and whole other universes might lie less than a millimeter away.


"In this view, 'dark matter' might be just ordinary matter," Arkani-Hamed suggests, "because the light from a star on a fold only one millimeter away might have to travel billions of light years 'along the wall' to reach us. Although we feel its gravity, we haven't seen it yet." A wide range of other puzzles might be solved if extra dimensions are real. And if we do the experiments, Arkani-Hamed says, "we have a good chance of seeing evidence for or against these ideas in the next ten years."


As recently as 1996 one science-writing pessimist was predicting the "end of science," asserting that what isn't already known never can be; his assumption has proved spectacularly wrong. Arkani-Hamed is one of several young theorists who suspect there may be more dimensions of space than meet the eye. By offering to solve some of physics' most intractable problems, their fresh ideas have revitalized science.

[Savage Beast]

Maybe that's what happened to me in Canyonlands. I said my name backwards and flipped into another dimension. Then I said it sideways and wasn't in any dimension at all. That's when I knew they were all illusions. That's one lesson I've never forgotten.

[RightWhale]

this kind of imbecilic posturing

You are correct. The scientist can only present his theory. It is up to the audience and the peers to play the part of avant-garde critics.

Scientists who oversell their pet ideas sometimes are classified as crackpots. It's not the idea itself that leads to such classification, it is the PR.

[Arkie2]

Yeah, but you'd have to send the check to the 5th dimension

[RightWhale]

This is consistent with Christian beliefs

It is, although many Christians are not aware of it. Also consistent with Islam. And Plato.

[scouse]

Wow!

[sweetliberty]

"God or perhaps God is"

Very much biblical as well...."I AM" is the greatest name of God or Yahweh from the Hebrew.

[RightWhale]

One of his papers.

He seems to be a recent Ph.D. capable of throwing out everything and starting over.

[freedomlover]

I just got around to seeing The Matrix (on DVD) two nights ago. I'm glad because I now understand this stuff a lot better.

[blam]

"Last I heard we were at 11 dimensions. That was several decades ago."

I read an article years ago about there being 10 dimensions. The only thing I remember about the article was that the writer believed that electro-magnetism was a consequence of something that was happening in another dimension. Hmmm

[Savage Beast]

It is interesting. And, when you think about it, we all live on different mental and spiritual diminsions, within paradigms, all the time and at the same time, superimposed upon one another, and these may not differ from different physical diminsions.

For example, while you're reading this, you're focused on what you're reading, but on some level you're aware of the room you're in and that the earth is round etc. This is important, because, though we can be aware of the illusory nature of the maya--and may other things on many other dimensions--we must function within our paradigms--milk the cows, pay the rent, avoid accidents, care for our children, study for exams.

It is also important not to confuse this with moral relativism. When we're functioning in the paradigm of everyday life--or in any paradigm for that matter--it is important to make sound decisions, including moral decisions. In fact, each of us is responsible for his own behavior and destiny. Certainly no one else is.

[Aurelius]

BUMP