Covariant quantum error correction in a three-layer quantum brain model: computational analysis of layer-specific coherence dynamics

2026/03/31 by Hikaru Wakaura · 1 voice
Biochemistry, Genetics and Molecular Biology · Physics and Astronomy · #q-bio.NC #physics.bio-ph #quant-ph

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arxiv published 2026/03/31 · arxiv updated 2026/04/13

Abstract

Quantum brain proposals require coherence on behaviorally relevant timescales, yet the gap between spin coherence times and neural decision windows has remained a quantitative obstacle. We evaluate approximate covariant quantum error correction (CQEC) -- a purification protocol constrained by the Eastin-Knill theorem -- across two radical-pair proteins parameterized by ab initio spin Hamiltonians: monoamine oxidase~A (MAO-A) and cryptochrome (CRY, PDB~4I6G). Both share a three-layer architecture (³¹P nuclear spin memory, electron spin interface, classical electrochemistry) and identical hyperfine coupling (A = 200~MHz), but differ 16-fold in nuclear T₂: 3.2~ms (MAO-A) versus 52~ms (CRY). We test whether CQEC preserves coherence over the 200~ms Schultze-Kraft veto window by mapping each protein's T₂ gap onto a simulation decoherence rate (γ_veto = T₂~gap/2T_sim): 3.08 for MAO-A, 0.19 for CRY. At γ_veto = 0.19, CQEC maintains tunneling coherence of 0.83 (95% CI [0.76, 0.79]; versus 0.12 without correction, ×6.9 improvement). At γ_veto = 3.08, coherence collapses to 0.012 even with CQEC. A T₂ sensitivity analysis confirms robustness: at T₂ = 26~ms (half the CRY estimate), CQEC-protected coherence remains 0.69. A classical Markov baseline produces only monotonic relaxation, confirming that CQEC-maintained oscillatory dynamics are genuinely quantum. However, no single protein optimizes both layers: CRY's shorter T₂^e (0.53~ns versus 1.1~ns) worsens Layer~2 fidelity. This layer-protein tradeoff, together with unresolved challenges in state preparation and entanglement distribution, defines the next targets for quantum brain research.

Citations

• The power of quantum neural networks
• A quantum-inspired classical algorithm for recommendation systems
• Quantum Information and Consciousness
• The Radical-Pair Mechanism of Magnetoreception
• Quantum Cognition: The possibility of processing with nuclear spins in the brain
• Quantum cognition: The possibility of processing with nuclear spins in the brain
• An accumulator model for spontaneous neural activity prior to self-initiated movement
• Restrictions on Transversal Encoded Quantum Gate Sets
• Unconscious determinants of free decisions in the human brain
• The Diffusion Decision Model: Theory and Data for Two-Choice Decision Tasks
• The Neural Basis of Decision Making
• Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems
• The importance of quantum decoherence in brain processes

Discussions

• Covariant quantum error correction in a three-layer quantum brain model: computational analysis of layer-specific coherence dynamics https://arxiv.org/abs/2604.08587 https://www.infiniteawareness.onli [bsky, 1 points, 0 comments]