Natural computation and its limits: Efim Liberman at the dawn of a new science.

Efim A. Liberman (1925-2011) can be considered as a founder of the new field of science that explores natural computation and its limits. He named it Chaimatics and suggested its generalization to the ultimate all-encompassing theory that unites biology, physics and mathematics. He made a number of experimental discoveries, including color coding in the retina, the participation mechanisms of Ca ions in synaptic transmission, and the measurement of potential in the coupling membranes of mitochondria and chloroplasts. He also made a decisive contribution to the proof of the chemiosmotic hypothesis of oxidative phosphorylation. In a series of works started in 1972, Liberman developed the concept of the molecular computer of the cell, which includes the programs written on DNA and RNA nucleotide sequences and executed by enzymes playing the role of processing units whereas nucleotide sequences are interpreted as commands and addresses. In this framework, Liberman predicted RNA splicing before its discovery and suggested the role of processing of small informational molecules (later defined as small RNAs) in controlling biological processes. Efim Liberman defined the fundamental property of life as a molecular and quantum computational system and introduced the idea of quantum computing inside a cell for making decisions on complex control tasks described by equations of mathematical physics. He approached the brain as a net of molecular computers and created a model of neuron operation based on the transmission of hypersound signals via cytoskeleton where the molecular computational system encodes the digital output. In 1979 Liberman published a hypothesis of human self-consciousness associated with not a chemical, but with a physical quantum coherent system and named it "extremal quantum regulator". We review here the contributions of Liberman in understanding the mechanisms of intracellular processing of information and his efforts to create an integrative theory of natural computation that aims to unite biology, physics and mathematics.