Continued from page 1
This is where
first of two major difficulties arose:
To determine what will happen in a specific experiment involving a specific particle and experimental setting – an observation must be made. This means that, in
absence of an observing and measuring human, flanked by all
necessary measurement instrumentation –
outcome of
wavefunction cannot be settled. It just continues to evolve in time, describing a dizzyingly growing repertoire of options. Only a measurement (=the involvement of a human or, at least, a measuring device which can be read by a human) reduces
wavefunction to a single solution, collapses it.
A wavefunction is a function. Its REAL result (the selection in reality of one of its values) is determined by a human, equipped with an apparatus. Is it recursive (TM computable and compatible)? In a way, it is. Its values can be effectively and mechanically computed. The value selected by measurement (thus terminating
propagation of
function and its evolution in time by zeroing its
other terms, bar
one selected) is one of
values which can be determined by an effective-mechanical method. So, how should we treat
measurement? No interpretation of quantum mechanics gives us a satisfactory answer. It seems that a probabilistic automaton which will deal with semi recursive functions will tackle
wavefunction without any discernible difficulties – but a new element must be introduced to account for
measurement and
resulting collapse. Perhaps a "boundary" or a "catastrophic" automaton will do
trick.
The view that
quantum process is computable seems to be further supported by
mathematical techniques which were developed to deal with
application of
Schrodinger equation to a multi-electron system (atoms more complex than hydrogen and helium). The Hartree-Fok method assumes that electrons move independent of each other and of
nucleus. They are allowed to interact only through
average electrical field (which is
charge of
nucleus and
charge distribution of
other electrons). Each electron has its own wavefunction (known as: "orbital") – which is a rendition of
Pauli Exclusion Principle.
The problem starts with
fact that
electric field is unknown. It depends on
charge distribution of
electrons which, in turn, can be learnt from
wavefunctions. But
solutions of
wavefunctions require a proper knowledge of
field itself!
Thus,
SE is solved by successive approximations. First, a field is guessed,
wavefunctions are calculated,
charge distribution is derived and fed into
same equation in an ITERATIVE process to yield a better approximation of
field. This process is repeated until
final charge and
electrical field distribution agree with
input to
SE.
Recursion and iteration are close cousins. The Hartree-Fok method demonstrates
recursive nature of
functions involved. We can say
SE is a partial differential equation which is solvable (asymptotically) by iterations which can be run on a computer. Whatever computers can do – TMs can do. Therefore,
Hartree-Fok method is effective and mechanical. There is no reason, in principle, why a Quantum Turing Machine could not be constructed to solve SEs or
resulting wavefunctions. Its special nature will set it apart from a classical TM: it will be a probabilistic automaton with catastrophic behaviour or very strong boundary conditions (akin, perhaps, to
mathematics of phase transitions).
Classical TMs (CTMs, Turing called them Logical Computing Machines) are macroscopic, Quantum TMs (QTMs) will be microscopic. Perhaps, while CTMs will deal exclusively with recursive functions (effective or mechanical methods of calculation) – QTMs could deal with half-effective, semi-recursive, probabilistic, catastrophic and other methods of calculations (other types of functions).
The third level is
Universe itself, where all
functions have their values. From
point of view of
Universe (the equivalent of an infinite TM), all
functions are recursive, for all of them there are effective-mechanical methods of solution. The Universe is
domain or set of all
values of all
functions and its very existence guarantees that there are effective and mechanical methods to solve them all. No decision problem can exist on this scale (or all decision problems are positively solved). The Universe is made up only of proven, provable propositions and of theorems. This is a reminder of our finiteness and to say otherwise would, surely, be intellectual vanity.

Sam Vaknin is the author of Malignant Self Love - Narcissism Revisited and After the Rain - How the West Lost the East. He is a columnist for Central Europe Review, United Press International (UPI) and eBookWeb and the editor of mental health and Central East Europe categories in The Open Directory, Suite101 and searcheurope.com.
Visit Sam's Web site at http://samvak.tripod.com