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arxiv: 2506.19184 · v3 · pith:4VCGMANWnew · submitted 2025-06-23 · ❄️ cond-mat.mes-hall · cond-mat.mtrl-sci

Real-Space Approach to Light-Induced Hall Transport in Disordered Materials

Jorge Martinez Romeral , Luis M.Canonico , Aron W.Cummings , Stephan Roche This is my paper

Pith reviewed 2026-05-19 07:17 UTC · model grok-4.3

classification ❄️ cond-mat.mes-hall cond-mat.mtrl-sci
keywords real-space transportlight-induced Hall conductivitydisordered graphenetime-resolved responsecircularly polarized lighttopological versus trivialfar-from-equilibrium dynamicsenergy relaxation
0
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The pith

A linear-scaling real-space method computes time-resolved Hall conductivity in driven disordered graphene and finds the signal generated in trivial systems but suppressed in topological ones, with the response persisting after the light is

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper presents a computational approach that tracks electrical currents in materials subjected to intense light pulses while incorporating both imperfections and energy dissipation on the same footing. When tested on gapped monolayer and bilayer graphene under circularly polarized light, the calculations produce a finite Hall conductivity in ordinary gapped sheets and eliminate it in those with topological properties. The resulting Hall signal oscillates throughout the drive and continues with sizable amplitude once the pulse ends before gradually returning to equilibrium. The calculations further indicate that realistic levels of disorder leave this dynamical response intact rather than destroying it.

Core claim

We introduce a linear-scaling real-space methodology to compute time-resolved electrical responses of materials driven far from equilibrium, with energy relaxation and disorder treated on equal footing. Applying this approach to gapped monolayer and AB-stacked bilayer graphene driven by a circularly polarized optical pulse, we observe the generation/suppression of a finite Hall conductivity when the system is trivial/topological. This Hall signal oscillates during optical driving and remains sizable after the light is switched off before relaxing toward equilibrium. Remarkably, this dynamical Hall response is robust in the presence of realistic descriptions of disorder, suggesting that and

What carries the argument

The linear-scaling real-space methodology for calculating time-resolved electrical responses far from equilibrium while treating disorder and energy relaxation equally.

Load-bearing premise

The linear-scaling real-space methodology accurately captures far-from-equilibrium dynamics, energy relaxation, and disorder effects on equal footing without introducing uncontrolled approximations that alter the predicted Hall response.

What would settle it

Time-resolved transport measurements on gapped graphene samples under circular light that either detect or fail to detect an oscillating Hall conductivity that survives after the pulse ends and matches the amplitude seen in simulations with added disorder.

Figures

Figures reproduced from arXiv: 2506.19184 by Aron W.Cummings, Jorge Martinez Romeral, Luis M.Canonico, Stephan Roche.

Figure 1
Figure 1. Figure 1: FIG. 1. Schematic of light-induced quantum transport in [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. Top panels: number of carriers multiplied by the density of states, for [PITH_FULL_IMAGE:figures/full_fig_p003_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. Top panel: Hall conductivity of BLG as a function [PITH_FULL_IMAGE:figures/full_fig_p004_3.png] view at source ↗
read the original abstract

We introduce a linear-scaling real-space methodology to compute time-resolved electrical responses of materials driven far from equilibrium, with energy relaxation and disorder treated on equal footing. Applying this approach to gapped monolayer and AB-stacked (Bernal) bilayer graphene, when driven by a circularly polarized optical pulse, we observe the generation/suppression of a finite Hall conductivity when the system is trivial/topological. This Hall signal oscillates during optical driving and remains sizable after the light is switched off before relaxing toward equilibrium. Remarkably, this dynamical Hall response is robust in the presence of realistic descriptions of disorder, suggesting that disorder and relaxation dynamics can be leveraged as design parameters rather than as limitations. More broadly, our new methodology enables the investigation of electrical responses in driven, complex disordered quantum materials and highlights how engineered energy-transfer pathways can enable ultrafast optoelectronic functionality.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The paper introduces a linear-scaling real-space methodology to compute time-resolved electrical responses of materials driven far from equilibrium, with energy relaxation and disorder treated on equal footing. Applying this to gapped monolayer and AB-stacked bilayer graphene under circularly polarized optical pulses, it reports generation of finite Hall conductivity in trivial systems and suppression in topological ones. The Hall signal oscillates during driving, remains sizable after the pulse is switched off before relaxing to equilibrium, and is robust to realistic disorder, positioning disorder and relaxation as potential design parameters.

Significance. If the methodology holds, the work provides a practical computational framework for studying ultrafast optoelectronic responses in large, disordered quantum materials that were previously inaccessible. The reported robustness of the dynamical Hall response to disorder is noteworthy and could inform device design strategies that exploit rather than avoid disorder and relaxation pathways.

major comments (2)
  1. [§2] §2 (Methodology description): The linear-scaling real-space time-evolution scheme is load-bearing for all claims of applicability to disordered systems, yet the manuscript provides no direct validation against exact diagonalization on small driven systems or recovery of the equilibrium Kubo Hall conductivity in the undriven limit. Without such benchmarks, it is unclear whether truncation or basis choices affect the predicted generation/suppression or post-pulse persistence.
  2. [§4.2] §4.2 (Graphene results): The distinction between trivial and topological cases is central to the generation/suppression observation, but the text does not specify how the topological character (e.g., via Berry curvature or Chern number) is diagnosed within the driven, relaxing, disordered simulation; this leaves open whether the reported contrast survives the approximations used.
minor comments (2)
  1. [Abstract] Abstract and §1: The term 'realistic descriptions of disorder' should be tied explicitly to the model parameters (e.g., disorder strength range and correlation length) used in the simulations.
  2. [Figures] Figure captions: Time traces should indicate the optical pulse envelope and the precise moment the drive is switched off to make the 'during' versus 'after' regimes unambiguous.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their thorough review and constructive feedback on our manuscript. We appreciate the positive assessment of the significance of our work. Below, we provide point-by-point responses to the major comments and indicate the revisions we will make.

read point-by-point responses

  1. Referee: [§2] §2 (Methodology description): The linear-scaling real-space time-evolution scheme is load-bearing for all claims of applicability to disordered systems, yet the manuscript provides no direct validation against exact diagonalization on small driven systems or recovery of the equilibrium Kubo Hall conductivity in the undriven limit. Without such benchmarks, it is unclear whether truncation or basis choices affect the predicted generation/suppression or post-pulse persistence.

    Authors: We agree that direct validation benchmarks would enhance the credibility of the methodology. Although the primary focus is on large-scale disordered systems inaccessible to exact methods, we will include in the revised manuscript a validation section demonstrating recovery of the equilibrium Kubo Hall conductivity in the undriven, clean limit. Additionally, for small driven systems, we will provide comparisons with exact diagonalization where feasible to confirm that our real-space approach reproduces the expected dynamics without significant artifacts from truncation or basis choices. These additions will be placed in Section 2 or as a supplementary appendix. revision: yes

  2. Referee: [§4.2] §4.2 (Graphene results): The distinction between trivial and topological cases is central to the generation/suppression observation, but the text does not specify how the topological character (e.g., via Berry curvature or Chern number) is diagnosed within the driven, relaxing, disordered simulation; this leaves open whether the reported contrast survives the approximations used.

    Authors: The topological classification is based on the equilibrium properties of the undriven system. Specifically, we compute the Chern number from the Berry curvature of the clean gapped bands to distinguish trivial (Chern number zero) from topological (nonzero Chern number) cases. In the simulations, the system is initialized in the corresponding equilibrium state, and the time evolution under driving, relaxation, and disorder is performed from there. We will revise the manuscript in §4.2 to explicitly describe this procedure, clarifying that the contrast is between systems with different equilibrium topological invariants, and that the dynamical Hall response maintains the distinction under the approximations employed. revision: yes

Circularity Check

0 steps flagged

No significant circularity detected in derivation chain

full rationale

The paper introduces a new linear-scaling real-space methodology for time-resolved responses in driven disordered systems and applies it to gapped graphene under circularly polarized pulses. The reported Hall conductivity generation/suppression, oscillations, and post-pulse persistence are presented as numerical outcomes of this independent computational framework rather than reductions to fitted parameters, self-definitions, or load-bearing self-citations. No equations or steps in the provided text equate predictions to inputs by construction; the central claims rest on the methodology's application to physical models without circular redefinition.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

Based solely on the abstract, the approach builds on standard quantum transport frameworks but introduces a new computational scheme. No explicit free parameters, invented entities, or ad-hoc axioms are detailed in available text.

axioms (1)
  • domain assumption Standard treatment of light-matter interaction in tight-binding models for graphene
    Invoked implicitly when applying the method to monolayer and bilayer graphene under circularly polarized light.

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