Operational Thermalization in Quasi-Local Algebras: Lieb-Robinson Contraction and the Rigorous Srednicki Limit
Roberto Isai Crotone
We present a mathematically rigorous W*-algebraic theory of the Eigenstate Thermalization Hypothesis (ETH) on quantum spin lattices, establishing operational thermalization as a continuous algebraic contraction. Constructing the physical framework as the inductive limit of local C*-algebras on Zd, we represent the thermodynamic system via the GNS construction as a hyperfinite II1 von Neumann factor M equipped with a faithful normal tracial state τ . The observer’s computational limits are strictly encoded by a local subalgebra N defined on a finite spatial support Λ ⊂ Zd . Utilizing Lieb-Robinson causal bounds and the non-commutative ergodic properties of asymptotically abelian systems, we prove that the conditional expectation onto N contracts to the tracial state in the operator norm. Furthermore, we derive the classical Srednicki ansatz directly from the concentration of measure on energy shells of the quasi-local net. Lastly, we analyze the mathematical obstruction of this algebraic contraction in integrable systems and Many-Body Localized (MBL) phases.
•Jun 15, 2026•0 citations