Transcript Extra Dimensions By Stephen Fennington, Mikhail Kuchuk, and Suhas Sreeharshan

Extra Dimensions
By Stephen Fennington,
Mikhail Kuchuk, and Suhas
Sreeharshan
Kaluza-Klein Theory
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The first theory to introduce extra
dimensions was the Kaluza-Klein theory,
which was first published by Theodor
Kaluza in 1921. Kaluza extended general
relativity into 5-dimensional space-time.
“In 1926, Oskar Klein proposed that the
fourth spatial dimension is curled up in a
circle of very small radius, so that a
particle moving a short distance along that
axis would return to where it began.”1
1:http://en.wikipedia.org/wiki/Kaluza-Klein_theory
Superstring Theory
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“Most promising
candidate…for
combining quantum
mechanics and
gravity.”1
String theory requires
ten dimensions! Seven
more than we are
used to dealing with.
There are seven tiny
curled up dimensions
in every point in
space.
1: Warped Passages
String theory basically postulates
that particles aren't points but
actually tiny vibrating strings.
How can there be more spatial
dimensions?
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Extra dimensions may be
hard to visualize but their
properties can be
determined mathematically.
If there are other dimensions,
where are they?
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“Theoretical physicists have
speculated that there might be
additional spatial dimensions that
escape our notice because they are
too small.”1
Each of these dimensions are less
than 10-33 cm. “One tenth of a
millionth of a trillionth of a
centimeter.” This is known as the
Planck length.
A piece of paper looks like it only
has length and width as a string
appears only to have length. We
over look their depth because it is
so small in comparison.
1: Warped Passages
How can we detect these extra
dimensions?
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“The curled up dimension
of the Kaluza-Klein
universe is…so small that
any variation within it is
[almost] imperceptible.”1
Using very sensitive
equipment, physicists can
check for violations of
conservation of energy due
to energy leaking into
other dimensions.
Similarly they can test for
fluctuations in the
gravitational force over
very small distances.
1: Warped Passages
2: The Quantum Universe
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“The extra dimensions are
microscopic, in which case
high-energy particle
accelerators and cosmic
ray experiments are the
only ways to detect their
physical effects.”2
Kaluza-Klein Particles
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Kaluza-Klein particles are particles that
travel through higher dimensional space
and carry extra-dimensional momentum.
If we were to detect them in our regular 4
dimensional space-time, they would carry
the charge of familiar particles with
heavier masses.
Physicists can examine the properties of
Kaluza-Klein particles to determine the
nature of high dimensional space.
Do Extra Dimensions really exist?
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As of yet, no
experiments have
proven that extra
dimensions exist.
This is in part because
of the tiny size of the
extra dimensions.
The Planck length size of
the curled up
dimensions is so small
that it would take
enormous energy to see
them directly, beyond
the reach of current
accelerators
A ray of hope!
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“The LHC will have direct sensitivity to extra dimensions 10 billion times
smaller than the size of an atom. A Linear Collider would determine the
number, size and shape of extra dimensions through their small effects on
particle masses and interactions.”
Why should we care about extra
dimensions?
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String theory requires 10
dimensions and is the
most promising candidate
for unifying all the forces
in one model.
Heavy particles proposed
by string theory may be
the elusive dark matter
particles.
“Particle physics seeks to
know if dark energy, dark
matter and cosmic
inflation are affected by
the physics of extra
dimensions.”1
1: Quantum Universe
That’s it for 10 dimensions!!
THE END
References
DOE/NSF. Quantum Universe: The Revolution in
21st Century Particle Physics.
Kaluza-Klein Theory.
http://en.wikipedia.org/wiki/Kaluza-Klein_Theory.
2/26/2007
Randall, Lisa (2005). Warped Passages. New York:
Harper Collins
String Theory.
http://en.wikipedia.org/wiki/String_theory
2/26/2007