activity
20242026
collaborators

6 papers

cond-mat.stat-mech2026

Hierarchical Lorentz Mirror Model: Normal Transport and a Universal Mean--Variance Law

Raphael Lefevere, Hal Tasaki

The Lorentz mirror model provides a clean setting to study macroscopic transport generated solely by quenched environmental randomness. We introduce a hierarchical version whose di…

cond-mat.stat-mech2026

The XY and XYZ models on the two or higher dimensional hypercubic lattice do not possess nontrivial local conserved quantities

Naoto Shiraishi, Hal Tasaki

We study the quantum spin system on the -dimensional hypercubic lattice with with uniform nearest-neighbor interaction of the XY or XYZ type and arbitrar…

cond-mat.stat-mech2025

Macroscopic Irreversibility in Quantum Systems: Free Expansion in a Fermion Chain

Hal Tasaki

We consider a free fermion chain with uniform nearest-neighbor hopping and let it evolve from an arbitrary initial state with a fixed macroscopic number of particles. We then prove…

cond-mat.stat-mech2025

Absence of nontrivial local conserved quantities in the quantum compass model on the square lattice

Mahiro Futami, Hal Tasaki

By extending the method developed by Shiraishi, we prove that the quantum compass model on the square lattice does not possess any local conserved quantities except for the Hamilto…

math-ph2025

Trees that can be grown in "too many" ways: A review of Bouch's construction

Hal Tasaki

We carefully review the hierarchical construction by Bouch [Bouch2015] of trees on the square lattice that can be grown from its root in distinct ways, where denotes t…

cond-mat.stat-mech2024

The Ground State of the S=1 Antiferromagnetic Heisenberg Chain is Topologically Nontrivial if Gapped

Hal Tasaki

Under the widely accepted but unproven assumption that the one-dimensional S=1 antiferromagnetic Heisenberg model has a unique gapped ground state, we prove that the model belongs…