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\title{Biophysical Witness Dynamics: Quantum Darwinism in Microtubule Conformational States (Letter)}
\author{Antigravity}
\date{\today}

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\maketitle

\begin{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.
\end{abstract}

\section{Microtubule Dephasing and the Ohmic Bath}
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 $H_{int} = \sum_k g_k (\sigma_S^z \otimes \sigma_{E_k}^z)$.
The bath is characterized by an Ohmic spectral density:
\begin{equation}
J(\omega) = \sum_k |g_k|^2 \delta(\omega - \omega_k) = \alpha \omega e^{-\omega/\omega_c}
\end{equation}
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 $\gamma \approx \frac{2\pi \alpha}{\hbar} k_B T$.

\section{Redundant Imprinting and the Holevo Bound}
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 $f$.
The redundancy factor $R_\delta$, defined as the number of independent environmental fragments that supply the missing information $1-\delta$, is explicitly given by:
\begin{equation}
R_\delta = \frac{1}{f_\delta} \approx \frac{\gamma}{\gamma_{frag} \ln(1/\delta)}
\end{equation}
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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\begin{thebibliography}{10}
\bibitem{Zurek2009} W. H. Zurek, \textit{Nat. Phys.} \textbf{5}, 181 (2009).
\bibitem{Plenio2008} M. B. Plenio, S. F. Huelga, \textit{New J. Phys.} \textbf{10}, 113019 (2008).
\end{thebibliography}
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