The ultimate goal of physics is to find the
all natural phenomena.
An essential guiding principle in the development of
physical theory is symmetry, in the sense that most natural
symmetry laws, telling that the action representing the
dynamics of the observed physics is invariant under some
The highly successful Standard Model is an outstanding example
Often people expect that beyond the Standard Model you will find a larger
In the search of the ultimate fundamental theory
one favoured scenario is the Grand Unification approach,
which so to speak repeats the Standard Model scheme. The idea
is that we should search for a force corresponding to a larger
symmetry group, which at lower energies breaks down to the symmetry
group corresponding to the forces we see there.
In the Random Dynamics approach, it is however not assumed that
the Standard Model tells you anything about its own extension.
If symmetry is one corner stone in the search for physical laws,
another guiding principle is simplicity. As inheritors
of Occam's razor
we have learnt to look for the simplest scheme, and believe
that the fundamental principles are by definition simple.
That does however not imply that Nature itself is "simple"
at a fundamental scale, on the contrary:
As we climb up the energy scale there are more
and more degrees of freedom, not only the degree of
symmetry, but also complexity increases with energy.
What goes on at a fundamental scale, like the Planck
scale, is probably enormously complicated and is most simply
described in terms of randomness.
This is the punch line of Random Dynamics, a theory
developed by Holger Bech Nielsen
at the Bohr Institute, and his collaborators.
Unlike the Grand Unification scheme, in the Random Dynamics approach
the natural laws are
expected to get more complicated at higher energy. It is only
by the formulation "the fundamental world machinery is essentially random"
that the Random Dynamics model is simple. If one would formulate the
details of the "laws", it would be exceedingly complicated!
The idea is that a sufficiently complex and general model
for the fundamental physics at (or above)
the Planck scale, will in
the low energy limit (where we operate) yield the physics we know.
The reason is that as we slide down the energy
scale, the structure and complexity characteristic
for the high energy level, are shaved away.
The features that survive are those that are common for
the long wavelength limit of any generic model of
fundamental supra-Planck scale physics.
The ambition of Random Dynamics is to "derive" all the known physical
laws as an almost unavoidable consequence of a random fundamental
"world machinery", which we take to be
a very general, random mathematical structure
, which contains non-identical elements and
some set-theoretical notions. There are also strong
exchange forces present, but
there is as yet no physics: at some stage
comes about, and then physics follows.
The physics that we experience at our low energy level emerge from this primal mathematical set, but since we have no means to achieve precise knowledge about the structure at the fundamental scale, we postulate that is merely a generic fundamental structure (possibly among many others) which gives rise to the world we observe.
A mathematical theory does not "mean" anything in itself, to interpret
it means to relate it to concepts that emerge from one's own,
sensory experience. These concepts are to be looked upon as "primitive", and
in this sense Random Dynamics is more Aristotelian than Newtonian.
We believe that we do not talk about "what is always there", because we
are in somehow
genetically adjusted to "what is always there". Therefore we tend to describe
not "what is always there", but the perturbations of "what is always there".
Only in crazy theories like Random Dynamics do we try to formulate "what is
In this connection Aristotle is better than Newton - in the sense that
there is always friction around, and what we really need to describe is the
concept of dynamics, like in F=ma. Initially the energy concept is not that necessary
- since we don't need the Hamiltonian to describe everything.
That the fundamental structure comes without differentiability
and with no concept of distance, that is,
no geometry, not even topology, implies an apriori lack of
locality in the model. We cannot
put in locality by hand, since the lack of geometry forbids locality to
be properly stated. Thus the principle of locality, taken say as a path way
Lagrangian density only locally depending on the fields,
cannot be put in before we have space and time.
Holger Bech Nielsen