arXiv subjects

Lior Oppenheim

Publications and source records attributed to Lior Oppenheim.

3 recordsLinked to original sources

arXiv2026

Improving CFT Operators Using Machine Learning

Finite-size effects limit the accuracy with which conformal data can be extracted from lattice simulations of critical systems. While action improvement suppresses some corrections to scaling, it does not address operator-dependent effects arising from imperfect lattice representations of continuum conformal fields. In this work, we propose a data-driven method for improving lattice operators themselves, constructing estimators with enhanced overlap with the corresponding primary operators of the continuum conformal field theory. We identify improved lattice representations of leading spin and energy operators in three two-dimensional critical systems: the Ising model, the q = 3 Potts model, and the dilute q = 3 Potts model. In all cases, the resulting operators exhibit reduced corrections to scaling and yield more accurate estimates of scaling dimensions compared to conventional lattice choices. The code and analysis workflows used to produce these results are made available in an accompanying GitHub repository.

cond-mat.str-el↗

arXiv2023

Machine Learning the Operator Content of the Critical Self-Dual Ising-Higgs Gauge Model

We study the critical properties of the Ising-Higgs gauge theory in $(2+1)D$ along the self-dual line which have recently been a subject of debate. For the first time, using machine learning techniques, we determine the low energy operator content of the associated field theory. Our approach enables us to largely refute the existence of an emergent current operator and with it the standing conjecture that this transition is of the $XY^*$ universality class. We contrast these results with the ones obtained for the $(2+1)D$ Ashkin-Teller transverse field Ising model where we find the expected current operator. Our numerical technique extends the recently proposed Real-Space Mutual Information allowing us to extract sub-leading non-linear operators. This allows a controlled and computationally scalable approach to target CFT spectrum and discern universality classes beyond $(1+1)D$ from Monte Carlo data.

cond-mat.str-el↗

arXiv2022

Incoherent chiral-induced spin selectivity

The observation of spin-dependent transport through organic chiral structures has sparked numerous fundamental and applicative questions ranging from biology to spintronics. By now, there is a broad consensus that the effect results from the combination of spin-orbit coupling and the systems' unique geometry. However, two key challenges remain. Firstly, accounting for the magnitude of the measured effect in light of the weak spin-orbit coupling in organic systems. Secondly, understanding its observation not only in tunneling-dominated short molecules, but also in longer ones where phonon-assisted hopping via localized states is operative. We focus on the latter and find that localization and the complete loss of coherence due to phonons do not impede strong spin polarization of charge carriers passing through the molecule. Moreover, hopping decouples the energy scale for observing spin-selective transport from the magnitude of the spin-orbit coupling. Thus, our result may explain the observation of large spin selectivity at room temperature and under large applied voltages.

cond-mat.mes-hall↗