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Abstract: Arithmetic-Geometric Quantum Statistical Mechanics
SAT = PHASE TRANSITION + GALOIS SYMMETRY BREAKING: The ShunyaBar functional \(Z_{SB}(\psi) = \mathrm{Tr}(e^{-\beta L_\psi}) \cdot \prod_{k=1}^\infty \left(1 - \frac{1}{p_k^{\Gamma_k(\psi)}}\right)\), where \(L_\psi\) is a state-dependent graph Laplacian encoding geometric interactions and \(\Gamma_k(\psi) = \beta \cdot \gamma_k(\psi)\) with constraint “tightness” \(\gamma_k(\psi) > 0\), embeds into a C*-dynamical system exhibiting phase transition at critical inverse temperature \(\beta_c = 1\). For \(\beta \leq 1\) (high temperature), there is a unique KMS\(_\beta\) state representing high symmetry. For \(\beta > 1\) (low temperature), there are infinitely many extremal KMS\(_\beta\) states parameterized by \(\hat{\mathbb{Z}}^\times \cong \mathrm{Gal}(\mathbb{Q}^{\text{cyc}}/\mathbb{Q})\), with spontaneous symmetry breaking under arithmetic action on zero-temperature states. This generalizes the Bost-Connes theorem while incorporating continuous geometric structure via the Laplacian, enabling efficient optimization through controlled phase transitions.
Theorem: Phase Transition and Symmetry Breaking in the ShunyaBar System
The ShunyaBar functional:
\[Z_{SB}(\psi) = \mathrm{Tr}(e^{-\beta L_\psi}) \cdot \prod_{k=1}^\infty \left(1 - \frac{1}{p_k^{\Gamma_k(\psi)}}\right)\]
where \(L_\psi\) is a state-dependent graph Laplacian encoding geometric interactions (e.g., variable-clause graph in SAT), and \(\Gamma_k(\psi) = \beta \cdot \gamma_k(\psi)\) with \(\gamma_k(\psi) > 0\) measuring normalized constraint “tightness” (low \(\gamma_k\) for satisfied constraints, high for violated), can be embedded into a C*-dynamical system exhibiting a phase transition at critical inverse temperature \(\beta_c = 1\). Specifically:
- For \(0 < \beta \leq 1\) (high temperature), there is a unique KMS\(_\beta\) state.
- For \(\beta > 1\) (low temperature), there are infinitely many extremal KMS\(_\beta\) states, parameterized by the group \(\hat{\mathbb{Z}}^\times \cong \mathrm{Gal}(\mathbb{Q}^{\text{cyc}}/\mathbb{Q})\), with spontaneous symmetry breaking under the arithmetic action on zero-temperature states.
This generalizes the Bost-Connes theorem to incorporate continuous geometric structure via the Laplacian, while preserving the arithmetic phase transition driven by the prime-weighted product.
Construction of the Dynamical System
1. Arithmetic Component: Deformed Zeta Function
The product term \(\prod (1 - p_k^{-\Gamma_k(\psi)})\) represents the Euler product for the reciprocal of a “deformed zeta function”:
\[\zeta_\psi(\beta) = \prod_k (1 - p_k^{-\beta \gamma_k(\psi)})^{-1}\]
where \(\gamma_k(\psi)\) are state-dependent exponents. For constraint optimization, we define \(\gamma_k = 1/v_k(\psi)\) with \(v_k\) a smooth violation measure, ensuring \(\gamma_k \to \infty\) for satisfied constraints and \(\gamma_k \to 1^+\) for violated ones to avoid poles in the zeta function.
2. Geometric Component: Laplacian Spectral Geometry
The trace \(\mathrm{Tr}(e^{-\beta L_\psi})\) represents the partition function of a quantum harmonic oscillator on the graph with Laplacian \(L_\psi = D_\psi - A_\psi\), where the degree matrix \(D_\psi\) and adjacency matrix \(A_\psi\) depend on \(\psi\) (weighted by violation gradients in optimization contexts). This geometric term captures the topological and spectral properties of the constraint satisfaction landscape.
3. C*-Algebra Construction
We define the C*-algebra \(A\) as the tensor product:
\[A = A_{\text{arith}} \otimes A_{\text{geom}}\]
where: - \(A_{\text{arith}} = C^*(\mathbb{Q}/\mathbb{Z}) \rtimes \mathbb{N}^\times\) is the Bost-Connes algebra, generated by phases \(e(r)\) for \(r \in \mathbb{Q}/\mathbb{Z}\) and isometries \(\mu_n\) for \(n \in \mathbb{N}^\times\). - \(A_{\text{geom}}\) is the graph C*-algebra associated with the variable interaction graph.
The algebra satisfies relations analogous to the Bost-Connes system: - \(\mu_n^* \mu_n = 1\), \(\mu_k \mu_n = \mu_{kn}\) (arithmetic relations) - \(e(r) e(s) = e(r+s)\), \(e(r)^* = e(-r)\) (phase relations)
- \(\mu_n L_\psi \mu_n^* = n L_\psi\) (geometric scaling)
The time evolution is defined as: - \(\sigma_t(\mu_n) = n^{it} \mu_n\) - \(\sigma_t(e(r)) = e(r)\) - \(\sigma_t(L_\psi) = L_\psi\) (fixed geometry, or scaled if state-dependent)
4. Hamiltonian and Representations
We construct representations \(\pi_\alpha\) on \(\ell^2(\mathbb{N}^\times) \otimes \mathcal{H}_\psi\) where \(\mathcal{H}_\psi = L^2(G_\psi)\) for graph \(G_\psi\). The Hamiltonian decomposes as:
\[H = H_{\text{arith}} \otimes I + I \otimes L_\psi\]
where \(H_{\text{arith}} \epsilon_k = \log k \cdot \epsilon_k\) on the arithmetic basis, tensored with \(L_\psi\) on the geometric part. The full partition function becomes:
\[Z(\beta) = \mathrm{Tr}(e^{-\beta H}) = \zeta(\beta) \cdot \mathrm{Tr}(e^{-\beta L_\psi})\]
Proof of Phase Transition
1. KMS Condition Verification
A state \(\phi\) is KMS\(_\beta\) if for all \(a, b \in A\), there exists a holomorphic function \(F_{a,b}(z)\) on the strip \(0 \leq \Re(z) \leq \beta\) such that: - \(F_{a,b}(t) = \phi(a \sigma_t(b))\) - \(F_{a,b}(t + i\beta) = \phi(\sigma_t(b) a)\)
For the arithmetic part, this follows directly from the Bost-Connes construction. For the geometric part, since \(L_\psi\) is self-adjoint positive semi-definite (spectrum \(\lambda_i \geq 0\)), \(e^{-\beta L_\psi}\) is trace-class for \(\beta > 0\), and the tensor ensures the combined condition via separation of variables.
2. High-Temperature Regime (\(\beta \leq 1\)) - Uniqueness
The unique KMS\(_\beta\) state on \(A_{\text{arith}}\) is the tracial state:
\[\phi_\beta^{\text{arith}}(e(a/b)) = b^{-\beta} \prod_{p \mid b} \frac{1 - p^{\beta-1}}{1 - p^{-1}}\]
On \(A_{\text{geom}}\), the Gibbs state:
\[\phi_\beta^{\text{geom}}(x) = \frac{\mathrm{Tr}(x e^{-\beta L_\psi})}{\mathrm{Tr}(e^{-\beta L_\psi})}\]
is unique due to ergodicity properties of graph algebras for connected graphs.
The tensor product state \(\phi_\beta = \phi_\beta^{\text{arith}} \otimes \phi_\beta^{\text{geom}}\) is the unique KMS\(_\beta\) state on \(A\), as any other would violate uniqueness in either factor via modular theory and Tomita-Takesaki decomposition.
3. Low-Temperature Regime (\(\beta > 1\)) - Multiplicity and Extremality
For the arithmetic part, extremal KMS\(_\beta\) states are parameterized by embeddings \(\alpha \in \hat{\mathbb{Z}}^\times\):
\[\phi_{\beta,\alpha}^{\text{arith}}(x) = \zeta(\beta)^{-1} \mathrm{Tr}(\pi_\alpha(x) e^{-\beta H_{\text{arith}}})\]
extremality follows from the irreducibility and inequivalence of representations \(\pi_\alpha\).
The geometric part retains a unique Gibbs state, but tensoring with arithmetic yields states:
\[\phi_{\beta,\alpha} = \phi_{\beta,\alpha}^{\text{arith}} \otimes \phi_\beta^{\text{geom}}\]
inheriting multiplicity from the arithmetic factor. Since \(\hat{\mathbb{Z}}^\times\) is infinite, there are infinitely many such extremal states.
4. Symmetry Breaking Analysis
The symmetry group \(\hat{\mathbb{Z}}^\times\) acts by automorphisms on \(A\) (arithmetic Galois action on phases \(e(r)\), trivial on geometry). At \(\beta > 1\), the action is free and transitive on extremal states \(E_\beta \cong \hat{\mathbb{Z}}^\times\), but each state \(\phi_{\beta,\alpha}\) has stabilizer subgroup:
\[G_\phi = \{ g \in \hat{\mathbb{Z}}^\times \mid g^* \phi = \phi \}\]
leading to spontaneous breaking since inner automorphisms act trivially.
At zero temperature (\(\beta \to \infty\)), weak limits of KMS\(_\beta\) states evaluate the arithmetic subalgebra in \(\mathbb{Q}^{\text{cyc}}\), with Galois action \(\gamma \phi(x) = \phi(\theta(\gamma) x)\) via class field theory, intertwining geometry via \(L_\psi\) with number theory.
5. Phase Transition at \(\beta = 1\)
At \(\beta = 1\), the zeta pole \(\zeta(1) = \infty\) induces a bifurcation. The unique high-temperature state “splits” into the low-temperature manifold via continuity of KMS states in \(\beta\) and the pole of \(\zeta(1)\), causing the trace to diverge and branch into character-parameterized states through residues and analytic continuation.
Mathematical Significance
The ShunyaBar phase transition theorem represents a fundamental synthesis of: - Number theory: via the arithmetic Bost-Connes structure - Spectral geometry: through the graph Laplacian component - Quantum statistical mechanics: through the C*-dynamical system framework - Computational complexity: via optimization applications
This grand unification of arithmetic and geometry through quantum statistical mechanics provides a new paradigm for understanding the relationship between discrete and continuous structures in complex systems.
The mathematical framework described here represents ongoing research at ShunyaBar Labs into the fundamental connections between number theory, spectral geometry, and quantum statistical mechanics. The phase transition mechanism offers a new approach to optimization and constraint satisfaction problems by leveraging the natural symmetries of arithmetic-geometric systems.
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Citation
@misc{iyer2025,
author = {Iyer, Sethu},
title = {Phase {Transition} and {Symmetry} {Breaking} in the
{ShunyaBar} {System}},
date = {2025-11-22},
url = {https://research.shunyabar.foo/posts/shunya-bar-phase-transition},
langid = {en},
abstract = {**SAT = PHASE TRANSITION + GALOIS SYMMETRY BREAKING**: The
ShunyaBar functional \$Z\_\{SB\}(\textbackslash psi) =
\textbackslash mathrm\{Tr\}(e\^{}\{-\textbackslash beta
L\_\textbackslash psi\}) \textbackslash cdot \textbackslash
prod\_\{k=1\}\^{}\textbackslash infty \textbackslash left(1 -
\textbackslash frac\{1\}\{p\_k\^{}\{\textbackslash
Gamma\_k(\textbackslash psi)\}\}\textbackslash right)\$ embeds into
a C*-dynamical system with arithmetic-geometric phase transition at
\$\textbackslash beta\_c = 1\$. This generalizes the Bost-Connes
theorem to incorporate continuous geometric structure while
preserving arithmetic phase transition, enabling efficient
optimization through controlled symmetry breaking.}
}