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Few terms in physics have ever
been
disputed as long as the cosmological constant L,
introduced in 1917 and later abandoned again by Einstein. The
discussion
about its physical meaning later had a vehement revival, when the
quantum
field theory interpreted it as a measure for the vacuum energy.Until
now,
however, there exists neither a satisfying term definition for the
cosmological
constant, nor an explicit statement of its numerical value. The
cosmologists
request a L
value that differs from zero, mainly because they believe to be able to
solve the problems of the plane space- time and of the world age hereby.
It has been tried to calculate a
numerical value for the energy density of the vacuum and by this for
the
cosmological constant, by means of the quantum field theory. But this
value
differs extremely (by the factor 10 120!)
from the vacuum energy density which would be in accordance with
astronomical
observations.
It is assumed that a much more basic
problem hides behind this discrepancy.
Probably, the mystery of the
cosmological
constant therefore is rated so high in the theoretical physics [7], p.
186:
„for the physicists, the problem
of the cosmological constant is on the very top of the list of
undisclosed
mysteries in science".
2.4 Unification of natural forces
As already mentioned before, it
is
hoped to find a mathematical model for the unification of all known
natural
forces
( electromagnetic, weak, strong
and gravitational interaction), by means of the super string theory.
[3], p. 220: The super string
theory leads us back to the origin of time, when all cosmic forces were
completely symmetrical and represented a primary super force."
According to the super string
theory,
the first symmetry fractioning took place at the Planck time, when the
universe was about 10 -43
seconds
old, and the gravitation was the first to separate from the remaining
natural
forces. By later symmetry fractioning, the other natural forces also
became
independent.
( see fig. 1 on p. 10)
In 1968, the theorists Weinberg,
Salom and Glashow succeeded to unify the electromagnetic with the weak
force into the electro weak force, on the basis of the calibration
symmetry
- the Yang-Mills-Theory. Since then, no major progress could be
achieved.
The unification of all natural forces received new impetus only in 1984
when Green and Schwarz introduced a super string model which
contained
enough symmetry to exclude certain anomalies of earlier string
theories.
But even with this, the breakthrough could not be achieved.
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