Thermalization, ETH and generalized Gibbs ensembles
Research context
theory comparison · conditional · As of 2026-10-10
ETH proposes that suitable local-observable matrix elements in many chaotic energy eigenstates have thermal structure, allowing narrow-energy isolated preparations to approach thermal local expectations.
Key knowledge
ETH proposes that suitable local-observable matrix elements in many chaotic energy eigenstates have thermal structure, allowing narrow-energy isolated preparations to approach thermal local expectations. Integrable systems with additional conserved charges can instead require a generalized Gibbs ensemble. Closed-system global entropy/unitarity and local relaxation are different statements; thermalization is not guaranteed for every Hamiltonian or observable.
Values and equations
ρ_GGE=Z⁻¹exp(−Σ_jλ_jQ_j)
- ρ_GGE
- Normalized generalized ensemble
- Q_j
- Chosen conserved charges with their own units
- λ_j
- Multipliers with reciprocal charge units
- Z
- Dimensionless normalizing trace
Conditions and scope
- Specify Hamiltonian, conserved charges, initial energy width, observable support and limit/order of limits; numerical evidence is model bounded.
- Localization, scars, integrability and prethermal windows can obstruct or delay thermal behaviour. A GGE requires an adequate charge set, not an arbitrary count of parameters.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Inspected §§4.1–4.3 and 8: narrow-energy states, local observables, numerical ETH evidence and generalized Gibbs alternatives; source check dated 2026-10-10. Scope is limited to the cited statements, equations and assumptions, not the whole publication.
2026-10-10 · Author source inspection of the displayed claim, model assumptions and equations; independent exact-content and branch-inventory review is a separate gate. Contemporary status is a dated snapshot, not a promise of ongoing monitoring.
Entry details
Permanent link to this entry ↗- Record identity
- research-physics-eth-gge-comparison
- Revision
- research.1
- Structured reference record
- Postgraduate & research reference