Transcript String/M-Theory - Wheaton College

Astronomy, OFotU
The String Landscape & Multiverse,
The Anthropic Principle, and
Anselm’s Ontological Argument
Dr. Gerald B. Cleaver
Wheaton College
26 Mar 2008
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Outline
 Intro
to String Theory
 Landscape of String Theory
 Anthropic Principle
 Anselm’s Ontological Argument
A10a     a  g abc b Ac .
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500 Physicists seeking Einstein’s final goal
the Theory of Everything (Physical)
Scientific Understanding of Universe
Sought in String (M) Theory
A10a     a  g abc b Ac .
10
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Science Fiction has become Science
Extra Dimensions (7 to be exact)
 Parallel Universes (at least 1 + maybe a few more)
 Multiple Universes (perhaps ~ 10100 to 500)
 Warped Spacetime
 Time before Time
 Future for the Universe

A10a     a  g abc b Ac .
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String Theory implies
nature of reality & existence is
more complex …
more beautiful …
yet more simple …
then ever imagined before!
Aa     a  g abc b Ac .
Visible Universe
13.7 billion
light years
In diameter
= 8 x1022 mi
trillion galaxies,
trillion stars per
galaxy
All Matter & Forces in the Universe
Unified by String Theory
Particles & Forces
Like Notes on a Violin String
B
A
♪♫
♪♫
C
D
♪♫
♪♫
E
♪♫
F
G
♪♫
String Interactions consistent w/
Relativity
Astronomy, OFotU
Quantum Mechanics
Requires String Theory w/
9 + 1 Dimensional Spacetime
Astronomy, OFotU
Strings have two vibrations – CW & CCW
Spin = # of Vibrations in our 3+1 Dim. Spacetime
Gravitons = Spin 2 Particles
= Strings w/ both vibes in 3+1 Dim S-T
Photons, Gluons, W+,-, Z (non-grav. force part.)
= Spin 1 Particles
= Strings w/ 1 vibe in 3+1 Dim S-T
& 1 vibe in 6 Dim Comp Space
SUSYMatter
= Spin 0 Particles
= Strings w/ both vibes in 6 Dim Comp
Space
9 Dim 3 Large Dim
+ 6 Compact Dim
Products of 6 Circular Directions
Forming
Spherical
or
Too Simple!
Toroidal
too simple to result in
Either the matter particles that exist …
Sean Carroll, From the Universe to the Laboratory,
http://pancake.uchicago.edu/~carroll
So more complex shapes investigated …
S. Carroll, http://pancake.uchicago.edu/~carroll
Or the force carrying particles …
Require
Calabi-Yau Compactification Shape
from 6 Compactified Dimensions
2 Dim Surface C-Y Surface—Need to extend to 6 Dim
jpierre
R. Brandenberger
Energy Modes
R. Brandenberger
String Duality
R. Brandenberger
Finite Initial Size and
Temperature of Universe
Nagging Problem for 1st Decade (1985-95):
Not Just 1 10-Dimensional String Theory
But 5!
www.sukidog.com/jpierre/strings/
Solution: Duality (Equality) of All 5
String Theories
www.sukidog.com/jpierre/strings/
Each ‘Theory” is SAME THEORY
IN DIFFERENT
MATHEMATICAL LANGUAGE
O
Й
‫א‬
‫ڜ‬
www.sukidog.com/jpierre/strings/
www.sukidog.com/jpierre/strings/
Membrane
String

w/ 10 Dim

w/ 11 Dim
R. Brandenberger
Two 9-brane “Universes”= “Us & Them”
and extra dimension between
Compactify 6 of the 9 Spatial
Directions of each Brane as Before
Horava et al.
Effective 5-Dimensional Theory
Horava et al.
Size of 5th Dimension?
10-33 cm < y < 0.1 mm
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S. Carroll, http://pancake.uchicago.edu/~carroll
Tests for sub-mm.directions
Fgrav = -Gm1m2/r2  -Gm1m2/r2+n
1/r2 form of gravity being tested.
Standard gravity verified down to 0.15 mm
at Univ. of Wash. with 97% confidence level
Manufacturing of
Stringy Blackholes!

If sub-mm. dimension then it may be possible to
produce gravitons and mini-black holes (with
peco-second half-lives) at Fermilab & CERN this
decade!

Mini-black holes have distinct decays
—easily identifiable!

Black Holes Detectors for
Fermilab and CERN
Proposed Explanation for Big Bang
Implying Time Before Time!
Single
Event
Astronomy, OFotU
Astronomy, OFotU
Cyclical
Events
The colliding Branes would not remain perfectly
flat as they approach each other due to quantum
effects.
Big Bang Inflations occurs in bumps on Branes
that collide first.
Multiple, separated, Big Bang regions might have
been formed from distinct collision points of
Branes!
 Multiple universes on our Brane besides 1+
Parallel Branes along an extra spatial direction
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S. Carroll, http://pancake.uchicago.edu/~carroll
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S. Carroll, http://pancake.uchicago.edu/~carroll
S. Carroll, http://pancake.uchicago.edu/~carroll
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S. Carroll, http://pancake.uchicago.edu/~carroll
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S. Carroll, http://pancake.uchicago.edu/~carroll
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Present view of universe from Milky Way
You are here
↓
Future view of universe from Milky Way, in ~ 1 Trillion Years
Milky Way torn up in a few more 100 Billion Years
Solar system torn apart in a few more 10 Billion Years
New Scientist, 5 Feb 2005
S. Carroll, http://pancake.uchicago.edu/~carroll
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S. Carroll, http://pancake.uchicago.edu/~carroll
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S. Carroll, http://pancake.uchicago.edu/~carroll
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String Landscape
C.C.
1
10-120
~ 10100 to 500 Models in M-Theory
String Landscape
C.C.
1
10-119
10-120
Anthropic Principle of String Theory
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Examination of the State of the Universe from
Anthropic Principle and Fine Tuning
Weak Anthropic Principle (WAP): "The observed values of all physical and
cosmological quantities are not equally probable but they take on values
restricted by the requirement that there exist sites where carbon-based life can
evolve and by the requirements that the Universe be old enough for it to have
already done so." (Barrow and Tipler 1986: 16).
The Merriam-Webster dictionary defines WAP as conditions that are
observed in the universe must allow the observer to exist.
Strong Anthropic Principle (SAP): "The Universe must have those properties
which allow life to develop within it at some stage in its history."
(Barrow and Tipler 1986).
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Barrow and Tipler then proposed three (overlapping) elaborations of the SAP:
(i) "There exists one possible Universe 'designed' with the goal of generating and
sustaining 'observers.' "
This implies that the purpose of the universe is to give rise to intelligent life, with the
laws of nature and their fundamental constants set to ensure that life as we know it
will emerge and evolve. Fine tuning of constants in nature result as necessities for
life.
(ii) "Observers are necessary to bring the Universe into being."
Barrow and Tipler believe that this can be validly inferred from quantum mechanics.
(iii) "An ensemble of other different universes is necessary for the existence of our
Universe."
This interpretation sympathizes with the many worlds interpretation of quantum
mechanics. We will see a possible reemergence of this in string theory
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Fine-Tuning: The premise of the fine-tuned universe assertion is that any small change
in the twenty or so physical constants would make the universe radically different and
therefore, unsuitable for life:
If, for example, the electron's charge were slightly different, or if the strong nuclear force
were only 2% stronger, di-protons would be stable and hydrogen would fuse too easily,
making stars as we know them impossible and prevent the universe from developing life
as we know it.
Or, if the cosmological constant had been greater than it is by a factor of 10, the
universe would have expanded to fast for galaxies to ever form.
Eternal
Inflationary
Universe
Each later universe has lower cosmological
constant than did the universe from which it
came.
String Cosmology implies physical creation is
likely eternal forward. God’s creative act never
ceases. Each universe produces an infinitude
of universes.
A. Linde, Banff, 2004
Understanding of String Landscape and our Universe in relation to it
Controversial topic at the moment—numerous papers
Domain walls, near-BPS bubbles, and probabilities in the landscape,
A. Ceresole et al., hep-th/0605266.
On the Geometry of the String Landscape and the Swampland,
H. Ooguri and C. Vafa, hep-th/0605264.
Cosmological Landscape From Nothing: Some Like It Hot,
A. Barvinsky and A. Kamenshchik, hep-th/0605132.
The Supersymmetric Vistas of the Supergravity Landscape,
T. Ortin, Annalen Phys. 15 (2006) 252.
Inflation, dark matter and dark energy in the string Landscape,
A. Riddle and L Urena-Lopez, astro-ph/0605205.
Eternal observers and bubbler abundances in the Landscape,
The Landscape 'avant la lettre'.
V. Vanchurin and A. Vilenkin, hep-th/0605015.
The Landscape 'avant la lettre‘,
Role of Anthropic Principle? Hotly debated in String/M-Theory: e.g.,
On making predictions in a multiverse: Conundrums, dangers, and coincidences,
A. Aguirre, astro-ph/0506519.
The Anthropic principle and the duration of the cosmological past,
M. Cirkovic, astro-ph/0505005.
Supersymmetry breaking in the anthropic landscape,
L. Susskind, hep-th/0405189.
Is there a string theory landscape: Some cautionary notes,
M. Dine, hep-th/0405189.
Multiple universes, cosmic coincidences, and other dark matters,
A. Aguirre and M. Tegmark, hep-ph/0409072
Is there a string theory landscape?
T. Banks et al., hep-th/0309170.
Can the universe experience many cycles with different vacua?
Y. Piao, hep-ph/0407258.
String/M-Theory as presently understood has a large parameter space of variables
(angles between each compactified direction, lengths of each, plus things called
fluxes and torques) each leading to universes (observable, hidden, or both) with
differing properties. On the order of > 10100 different universes all seem equally
possible. Why our particular String/M-Theory universe?
Some scientists (e.g. Stephen Hawking) are suspicious that determination of a
particular choice of ALL of the M-Theory parameters might not be totally
determinable, based on Gödel’s Theorem, which says that one cannot formulate a
finite system of axioms to prove every result in mathematics. This means that
inconsistencies or indeterminacies can arise if one tries to prove statements that
refer to themselves.
A physical theory is a mathematical model. So if there are mathematical results
that cannot be proved, there are physical problems that cannot be solved. We do
not live outside of the universe, but instead we and our theories are both part of
the universe we are describing. Hence our theories are also self-referring. And thus
we might suspect that any Theory of Everything determined by a finite number of
known parameters or variables might ultimately be incomplete or undetermined!
Multiverse
necessitates Augustine’s Block Universe view:
God beyond all creation-beyond of all spacetimes.
Histories of all spacetimes appear as a moment
Multiverse
Anselm’s Ontological Argument:
God is that than which nothing greater can be
conceived. (Proslogion, Chap. 2, c. ~ 1100 A.D.)
A10a     a  g abc b Ac .
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Philosophical and theological issues raised by String/M-Theory and the
Multiverse Picture:

Immensely expanded concept of (10+1)-dimensional reality and
multiple universes has profound implications for meaning of
transcendence of God

Poses problems to process theology concept of God evolving with and
within a universe.

The (10+1)-dimensional bulk universe might be compared to St.
Augustine’s concept of block universe.
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String/M-Theory
Provides deeper understanding of spacetime and
reality
Presents our universe with a simplicity, order, and
beauty never before imagines. Simultaneously provides
for complexity of the (multi/uni)-verse
Suggests more to our universe than ever before
imagined.
Has implications for theological views of God regarding
meaning of transcendence—expanded view of
Augustine’s block universe.
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Interesting String (Cosmology) Web Sites (also image sources):
http://www.superstringtheory.com/ John Schwarz’ "The Official String Theory Web Site"
http://www.sukidog.com/jpierre/strings/ String Tutorial with glossary, refs & links
http://www.superstring-theory.com/EnglishVersion.html another excellent intro
http://www.superstringtheory.com/cosmo/index.html
http://www.ba.infn.it/~gasperin/
http://feynman.princeton.edu/~steinh/ Great string cosmology sites
http://www.nuclecu.unam.mx/%7Ealberto/physics/string.html
http://dmoz.org/Science/Physics/Quantum_Mechanics/
http://pages.wooster.edu/bboroson/clinks.html
worthwhile collections of links to other major string sites
** http://pancake.uchicago.edu/~carroll **
Several slides in the presentation borrowed from this site!