NSF grant to IU researcher funds study of 'fundamental length'

Mar 23, 2010

The National Science Foundation has awarded a $221,660 grant to Indiana University faculty member Amit Hagar for the first comprehensive study of fundamental length, a concept that has intrigued theoretical physicists off and on for nearly a century.

The three-year grant from the NSF Division of Science, Technology and Society to Hagar, an assistant professor in the Department of History and Philosophy of Science in the College of Arts and Sciences, will support study of the idea that space, rather than being continuous, is made up of discrete units.

Titled "Length Matters: The History and the Philosophy of the Notion of Fundamental Length in ," the project will combine philosophy with written and oral history, including interviews with leading figures in the debate over fundamental length. It will seek to bring light to some of the most pressing methodological issues in modern theoretical physics.

"The study will consider the diverse scientific and philosophical motivations for introducing the notion of fundamental length into modern theories of physics," Hagar said. "The discussion will characterize and then analyze the possible phenomenological consequences of this notion, which are currently at the center of heated debates among high-energy physicists who are struggling to unify the general with ."

It may seem self-evident that space is a continuum which can be divided into an infinite number of ever-smaller units, and that there is no "fundamental" unit of length. But Hagar points out that scientific advances have often involved "shifts in perspective" that allow us to see the world in new ways -- much as understanding the Earth's rotation demolished the idea that the Sun was circling the Earth.

In the case of fundamental length, the notion goes back to the ancient Greek philosopher Zeno, whose paradoxes exposed tension between views of space as infinite and discrete. In the 1930s, Werner Heisenberg and other physicists were drawn to the concept of fundamental length as they attempted to write down a quantum theory of electromagnetism. But the idea was largely rejected as impossible to reconcile with established findings.

Remarkably, Hagar said, the notion of fundamental length made a comeback in the 1950s and '60s with efforts to develop a theory of quantum gravity, a next step in the attempt to develop a unified theory that has driven for decades. But incorporating the idea will not be easy. It would require a theoretical structure that allows for new predictions while maintaining agreement with well-established principles.

"This challenge, currently faced by theories of quantum gravity, is also what makes the story of the notion of fundamental length so timely," Hagar said, "as it best exemplifies the delicate balance between conservatism and innovation that characterizes the practice of extending 'old' physics into new regimes."

Hagar has previously published two chapter-length articles on the history and philosophy of the concept of fundamental length. The grant will enable him to produce six more chapters, resulting in the first extended monograph on the topic.

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broglia
1 / 5 (1) Mar 23, 2010
The concept of minimal length is observer dependent. For example, the interior of black hole would appear like chaotic continuum for outer observer from outside. But when we get more closer, some density fluctuations would dissolve and some more distant one would appear. It's simmilar to observation of foggy landscape under haze - when we get closer, the new reality emerges, while some more distant one will dissapear.

http://www.newsci...zon.html

The whole model is complicated by the fact, observer would gradually dissolve in dense vacuum of black hole, too. Therefore the reality inside of black hole is virtual: for rather weak and brittle creatures it appears like very hot and dense gas, but for some very dense objects it could appear like rather transparent and could environment. Of course, such object would evaporate outside of black hole, instead - which makes notion of interior and exterior relative too.
Maxims
1 / 5 (1) Mar 23, 2010
Sounds like Heim theory where the unit of fundamental length is the metron. It can correctly derive particle masses and is a unified theory.

http://en.wikiped...m_theory
broglia
1 / 5 (1) Mar 23, 2010
The basic question here could be, whether inside of black holes the Planck length is really distance scale limit, or whether some other, a much smaller distance scale could exist there for potential observers existing there. You can read some works of prof. Amit Hagar there:

http://mypage.iu....pub.html

broglia
1 / 5 (1) Mar 23, 2010
Sounds like Heim theory where the unit of fundamental length is the metron. It can correctly derive particle masses and is a unified theory.
I presume, Heim theory is relevant for our conditions, in proximity of black hole the electron existing here would "swell" in dense vacuum around it and it would become more lightweight, then Heim's theory predicts. Near black hole nearly every matter would evaporate to accretion radiation, only most dense and primitive particles would remain. Interesting question is, whether some more dense electrons could exist, whose properties would be in relation in another stable particles existing there. Such particles may not be directly observable by us, because they would appear like semitransparent neutrinos from outside.
broglia
1 / 5 (1) Mar 23, 2010
Some theories are intepreting space-time expansion like fall into giant black hole - the energy spreads more slowly gradually and the space-time expands. In accordance with this model we can experience gradual swelling of iridium prototypes: iridium prototype "swells" and the kilogram prototype is losing weight.

http://www.physor...759.html
http://www.physor...s64.html

Recently another experimental evidence of space-time expansion was found

http://www.opfocu...&s=4

http://physics.ve...699.html

Not that in this model the light speed as measured by interference of light in vacuum remains invariant - what is changing there is the light speed, determined/compared by using of solid rulers or planetary systems, which doesn't expand so fast, like surrounding space-time.
broglia
1 / 5 (2) Mar 23, 2010
The swelling of matter could make observational evidence of dark matter illusory, because the expansion of space-time is determined by using of standard candles, i.e. Cepheid supernovas, which would become less and less stable (and bright) in vacuum gaining density. As you can see, the invariant interpretation of observational data isn't so straightforward, as it may appear at the first look.

http://opa.yale.e...?id=7354
http://www.entang...dle.html
jonnyboy
2.7 / 5 (3) Mar 23, 2010
I just love it when the comments are the most interesting part of the story. It appears to me that what we (US taxpayers) are paying is $75K a year for 3 years for someone to write the history of the concept of fundamental length. IMHO this is nothing but an incredible waste of precious resources.
panorama
2 / 5 (1) Mar 23, 2010
I just love it when the comments are the most interesting part of the story. It appears to me that what we (US taxpayers) are paying is $75K a year for 3 years for someone to write the history of the concept of fundamental length. IMHO this is nothing but an incredible waste of precious resources.


Agreed.
axemaster
not rated yet Mar 23, 2010
Lol all you guys talking about Heim Theory... you are aware that Heim theory is only any good because the experimental values were inserted into the theory by hand? It doesn't have any predictive value whatsoever.
Slotin
1 / 5 (3) Mar 23, 2010
IMO fundamental length is rather the wavelenght of cosmic microwave background radiation (CMB: ~ 1.9 cm), which defines the middle of dimensional scale in our Universe. The photons of longer wavelength tend to disperse in such noise like tachyons of negative rest mass, while the photons of shorter wavelength are of positive mass and they tend to condense mutually by their gravity. The universe is negativelly curved above this size (we are observing it from inside with positive gravity and time arrow), positivelly curved bellow this scale (small objects are observed from outside and they disperse). Note that the wavelength of solitons inside of human brain is of the approximatelly the same size - we are adopted to it, as it minimizes the dispersive effects (even capillary waves at the wave surface are of the same wavelength).

Note that CMB is corresponding the Hawking radiation of small black hole (~ 2 cm in diameter), whose lifespan corresponds exactly the age of observable Univers
Slotin
1 / 5 (2) Mar 23, 2010
..experimental values were inserted into the theory by hand? It doesn't have any predictive value whatsoever.

Just try to google for the sentence "I can now say for certain that the A matrix is not involved with this new version" and you'll see, the post of yours is not relevant for reality. After all, source code for Heim's formula implementation is freely available and everyone can make sure, it doesn't contain any arbitrary numerical constants other then the fundamental ones.

http://www.daimi....Formula/

Of course, many proponents of string theory and other mainstream theories aren't very happy from this fact because of competition.
frajo
5 / 5 (1) Mar 24, 2010
the expansion of space-time is determined by using of standard candles, i.e. Cepheid supernovas,
What is a Cepheid supernova?
MarkmBha
1 / 5 (1) Mar 24, 2010
This is an amazing article. The comments are equally amazing!
antialias
not rated yet Mar 25, 2010
Soooo..instead of funding a scientific search for the fundamental length (or whether there even is one) they are funding someone to go ask _others_ what they think about the fundamental length? That is a brilliant way of getting answers....NOT.

Reminds me a lot of how they tried to find out the length of the chinese emperor's nose (who was in the forbidden city where no one could see him) by going out into the countryside and taking a census on what people thought.

Sure, you'll get an answer - but it won't be worth anything.
stealthc
1 / 5 (1) Mar 27, 2010
yeah I think that guy should take his hot air writing, and make a book out of it, and sell it. What's the bother paying this tool for work which he'll probably exploit for his own benefit anyways? Why are we paying for him to write a book for himself?
ebnv
not rated yet Mar 28, 2010
I just love it when the comments are the most interesting part of the story. It appears to me that what we (US taxpayers) are paying is $75K a year for 3 years for someone to write the history of the concept of fundamental length. IMHO this is nothing but an incredible waste of precious resources.


Why isn't there an IQ test before you can post?
ebnv
5 / 5 (1) Mar 28, 2010
....more on jonnyboy post....
Answering questions as to whether the Planck length is merely an observational limit or physical limit is fundamental to our understanding of the universe.
An effort to tease ideas from all quarters of science can hardly be termed wasteful... except in the simplest of minds I suppose.
"It will seek to bring light to some of the most pressing methodological issues in modern theoretical physics."
no value here either, yeah?
It is no wonder that the US is dead last in scores on science and mathmatics in the industrialized world when the prevaling feeling among most americans is that math and science are a waste.. ggrrrr
frajo
not rated yet Mar 28, 2010
Answering questions as to whether the Planck length is merely an observational limit or physical limit is fundamental to our understanding of the universe.
The Planck length could well have no physical meaning at all. It's just a speculative combination of certain physical values where the result is a length.
We don't even know whether the constant of gravitation still is a constant at distances smaller than, say, 0.01 mm. We simply can't measure gravitation between objects which are at a distance of less than 10**30 Planck lengths.
antialias
not rated yet Mar 28, 2010
Answering questions as to whether the Planck length is merely an observational limit or physical limit is fundamental to our understanding of the universe.

Sure, but do you think an assistant professor of the History of Science and Philosophy in an 'Arts and Sciences' department is qualified to even understand the subject matter (much less make a qualified contribution)?

Somehow I doubt that.

It would be like a casual reader of physorg making a significant contribution to quantum mechanics.
hush1
3 / 5 (2) Mar 31, 2010
Shakespeare?

To continue or not to continue. That is here discrete.

I pass. Cantor's heroics are still unmeasurable.
fullbony
1 / 5 (1) Apr 04, 2010
most of physics will come to an end when experimentation cannot be done due to energies beyond our grasp. if and when we are able do these experiments will come an advancement in the field. until then physics will be a self fulfilling prophecy of filling in the right numbers to make us happy ( and funded ).