The Penrose-Hameroff Orch-OR hypothesis proposes that tubulin dimers in a neuron's microtubules can hold a superposition of two conformational states. Each superposed dimer displaces a tiny amount of mass between the two states, so the coherent ensemble carries a gravitational self-energy difference EG between the branches of the superposition. Penrose's objective-reduction criterion (after Diosi) says the superposition survives only for a finite time before gravity itself forces a definite outcome:
τ = ħ / E_G (Diosi-Penrose collapse time)
E_G ≈ k_G · N² (self-energy of N coherently superposed dimers)
This simulation tracks N(t), the number of tubulin dimers currently held in superposition, and integrates EG(t) over time. When the accumulated phase EG·t/ħ reaches 1, an objective-reduction event fires: every superposed dimer collapses to a definite classical state simultaneously — in the Orch-OR picture, one "orchestrated" moment of conscious experience, hypothesised to recur near 40 Hz (gamma-band) when the lattice is fully recruited.
- Recruitment rate — how fast unrecruited dimers are driven into superposition; this is the "orchestrating" input from microtubule-associated proteins (MAPs) in the original hypothesis.
- Thermal decoherence — the per-second chance a superposed dimer is knocked back to a classical state by warm, wet cytoplasm before OR can occur — the central objection critics raise against Orch-OR (Tegmark 2000).
- Gravitational coupling kG — scales EG, i.e. how quickly self-energy accumulates toward the ħ threshold; a stand-in for the (still unmeasured) effective mass displacement per dimer.
- Anesthetic pulse — general anesthetics are hypothesised (controversially) to suppress tubulin quantum coherence directly; the pulse zeroes recruitment for a few seconds so no OR events can fire, mimicking loss of consciousness.
This remains a speculative, heavily contested theory — mainstream neuroscience holds that warm biological tissue decoheres far too fast for this mechanism to matter, and no experiment has confirmed gravitationally-induced collapse in microtubules. The model above implements the proposed mechanism faithfully so you can see exactly what it would predict, not a claim that it is correct.