Coarse-grained Bootstrap of Quantum Many-body Systems
arXiv:2412.07837
Abstract
We present a new computational framework combining coarse-graining techniques with bootstrap methods to study quantum many-body systems. The method efficiently computes rigorous upper and lower bounds on both zero- and finite-temperature expectation values of any local observables of infinite quantum spin chains. This is achieved by using tensor networks to coarse-grain bootstrap constraints, including positivity, translation invariance, equations of motion, and energy-entropy balance inequalities. Coarse-graining allows access to constraints from significantly larger subsystems than previously possible, yielding tighter bounds compared to those obtained without coarse-graining.
v1: 10 figures, public code included, v2: moved example code to anc folder, v3: minor error fixed and small adjustments, v4: small adjustments