Feasibility analysis of the surface code model for the Orch-OR microtubule.

Abstract

Although the Orch-OR theory has been recognized as one of the quantum models of consciousness, it faces significant challenges due to the fragility of quantum coherence within the warm, wet, and noisy environment of the brain. In this work, we propose a potential resolution by invoking a quantum error-correction framework, specifically focusing on the surface code model. We hypothesize that the brain may inherently employ a quantum error-correction mechanism of this form. Accordingly, we first examine how the surface code protocol can be conceptually mapped onto the microtubule structure. We then analyze the attainable quantum coherence time under the surface code in comparison with the coherence time required by the Orch-OR framework. As a subsequent step, we derive feasibility conditions under which the surface code can sustain coherence times exceeding those necessary for the Orch-OR mechanism. Finally, we investigate whether the structural and dynamical properties of microtubules - such as the number of tubulin dimers and their associated error rates - can realistically satisfy these feasibility conditions. Our analysis demonstrates that the surface code model may enable quantum coherence times sufficiently long to support the requirements of the Orch-OR theory. On this basis, we argue that the Orch-OR framework retains partial validity in explaining the emergence of consciousness in the brain.