New Perspective on Detection and Dephasing in Two-Dimensional Electronic Spectroscopy
Coherent multidimensional spectroscopy enables the identification of spectral structure and quantum dynamics with remarkable detail. Over the past two decades, the chemical physics community has leveraged these capabilities to address key problems across chemistry, materials science, and condensed matter physics. Yet, the information content encoded in these experiments is far richer than what is routinely extracted.
We are pleased to share our new Perspective, recently submitted for publication and now available on arXiv:
This work advances a central conceptual idea emerging from our recent efforts in ultrafast nonlinear spectroscopy: the measured homogeneous linewidth is not determined solely by a material’s intrinsic quantum dynamics, but also by the observable through which those dynamics are projected experimentally.
In other words, detection is not merely a means of measuring a multidimensional spectrum—it is a constitutive part of what the spectrum fundamentally represents.
Using a unified theoretical and simulation framework, we demonstrate that coherent emitted-field detection and action-detected approaches (including photoluminescence, photocurrent, and related observables) can yield distinct operational definitions of dephasing, even when probing the same underlying many-body dynamics. More broadly, these results point toward the evolution of multidimensional spectroscopy from a general probe of coherence into a platform for observable engineering in complex quantum materials.
This direction forms a central component of the scientific strategy of the CERC Interaction lumière–matière / Light–Matter Interactions and the Institut Courtois, with the goal of designing nonlinear spectroscopies that selectively access the correlations, relaxation pathways, and emergent dynamics most relevant to materials functionality and quantum condensed matter.
We are especially pleased to highlight that this is Simón Paiva’s first first-author publication of his PhD, marking an important milestone and the beginning of a promising research trajectory.
We thank Simón Paiva-Ortega, Hao Li, and Eric Bittner for their collaboration and intellectual partnership on this project.
