39 lines
2.7 KiB
Markdown
39 lines
2.7 KiB
Markdown
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---
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title: "Research Paper: Biophysical Witness Dynamics: Quantum Darwinism in Microtubule Conformational States (Letter)"
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date: "2026-06-01T08:00:00Z"
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draft: false
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tags: ["#research", "physics", "intellecton"]
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---
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**Abstract:** We apply the principles of Quantum Darwinism to the conformational dipole states of tubulin dimers within cellular microtubules. By defining a pure dephasing interaction with an Ohmic aqueous thermal bath, we formally parameterize the decoherence rate $\gamma$. We calculate the Mutual Information $I(S; E_F)$ across multiple independent acoustic phonon fragments. By demonstrating that the Holevo bound is saturated, we compute the explicit redundancy factor $R_\delta$, proving that stable, classical tubulin pointer states are robustly imprinted into the biological environment.
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## Microtubule Dephasing and the Ohmic Bath
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Let a single tubulin dimer be modeled as a two-level open quantum system representing its conformational dipole, $H_S = \frac{\omega_0}{2} \sigma_S^z$. The environment consists of acoustic phonon modes in the intra-cellular fluid. We define a pure dephasing interaction $H_{int} = \sum_k g_k (\sigma_S^z \otimes \sigma_{E_k}^z)$.
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The bath is characterized by an Ohmic spectral density:
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$$
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J(\omega) = \sum_k |g_k|^2 \delta(\omega - \omega_k) = \alpha \omega e^{-\omega/\omega_c}
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$$
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where $\alpha$ is the dimensionless coupling strength derived from molecular dipole-water interactions, and $\omega_c$ is the high-frequency cutoff of the solvation shell. At biological temperatures $T=310$ K ($k_B T \gg \omega_c$), the Markovian decoherence rate is explicitly parameterized as $\gamma \approx \frac{2\pi \alpha}{\hbar} k_B T$.
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## Redundant Imprinting and the Holevo Bound
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We partition the cellular environment into disjoint fragments $E_F$. The mutual information $I(S; E_F)$ scales with the fragment size $f$. For pure dephasing, the environment perfectly records the pointer states (the diagonal elements of $\rho_S$). The Holevo bound $I \approx H(S)$ is saturated for small fractions $f$.
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The redundancy factor $R_\delta$, defined as the number of independent environmental fragments that supply the missing information $1-\delta$, is explicitly given by:
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$$
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R_\delta = \frac{1}{f_\delta} \approx \frac{\gamma}{\gamma_{frag} \ln(1/\delta)}
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$$
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Given the massive degrees of freedom in the biological solvation shell, $R_\delta \gg 1$, proving that numerous independent biochemical pathways can concurrently deduce the classical conformational state of the tubulin dimer without perturbing its Hamiltonian.
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## References
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- **[Zurek2009]** W. H. Zurek, *Nat. Phys.* **5**, 181 (2009).
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- **[Plenio2008]** M. B. Plenio, S. F. Huelga, *New J. Phys.* **10**, 113019 (2008).
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