ULTIMATE COMPUTING - Quantum Consciousness Studies

Toward Ultimate Computing 21
(1981) proposed that solitons could propagate through switching circuits made of
branched polyacetylene chains. He has also considered molecular computing in
periodic arrays using electron tunneling, soliton “valving” and photo-activated
conformational changes in lattice materials. He envisions three dimensional
molecular scale memory and switching densities of 10 15 to 10 18 elements per
cubic centimeter, near the theoretical limit for charge separation. A number of
materials may be suitable for soliton switching and biological propagation of
solitons in proteins has been suggested. Several authors have argued for
cytoskeletal solitons mediating information processing (Chapter 8).
Wayne State University’s Michael Conrad has defined his vision of a
molecular computer in which proteins integrate multiple input modes to perform a
functional output (Conrad, 1986). In addition to smaller size scale, protein based
molecular computing offers different architectures and computing dimensions.
Conrad suggests that “non-von Neumann, nonserial and non-silicon” computers
will be “context dependent,” with input processed as dynamical physical
structures, patterns, or analog symbols. Multidimensional conditions determine
the conformational state of any one protein: temperature, pH, ionic
concentrations, voltage, dipole moment, electroacoustical vibration,
phosphorylation or hydrolysis state, conformational state of bound neighbor
proteins, etc. Proteins integrate all this information to determine output. Thus
each protein is a rudimentary computer and converts a complex analog input to
an output state or conformation.
Conrad and Liberman (1982) have defined an “extremal computer” as one
which uses physical resources as effectively as possible for computation. They
suggest that an extremal computer should be a molecular computer, with
individual switches or information representation subunits composed of
molecules. The state of each information. subunit should be coupled to an energy
event near the quantum limit. Protein conformational states leveraged to dipole
oscillations in the nanoscale may be that limit. Conrad and Liberman conclude
that, within biological systems, macromolecular computing occurs by
conformational changes generating “reaction diffusion patterns” of concentrations
of biochemical energy molecules (cyclic AMP).
A 1984 conference (Yates, 1984) considered Chemically Based Computer
Designs (Yates, 1984) and attempted to answer 6 relevant questions. 1) Are there
fundamental, quantum mechanical limitations on computation This question
deals with energy loss due to friction or other factors in computation. The work of
Benioff (1980, 1982), Landauer (1982) and Feynman (1986) lead to the
conclusion that, in principle, computation can be achieved by a frictionless,
energy conserving system. Thus there appear to be no quantum mechanical
limitations on computation. 2) Are there fundamental, thermodynamic limitations
on computation Although there are some computing operations that are
irreversible and dissipative, the work of Landauer (1982) and Bennett (1982)
show that there are no fundamental thermodynamic limitations on computation
per se. 3) Are there fundamental limits to serial processing on digital computers
based on binary switches This question has philosophical implications (does the
universe function through continuous or discrete processes) and so cannot be
answered assuredly. The consensus of the conference was that there are probably
limits on serial, digital computing. 4) What are the practical physical limitations
on computer design There are several practical limitations to the further
miniaturization of digital switching circuits. However those limits probably won’t
be reached for decades. 5) What are the potential contributions of molecular
electronics to digital computer design The conference considered molecular
conformational changes, solitons, charge flow and other approaches. Molecular