Momentum-Resolved Two-Dimensional Spectroscopy as a Probe of Nonlinear Quantum Field Dynamics
Year: 2026
Type: article
Abstract: Emergent collective excitations constitute a hallmark of interacting quantum many-body systems, yet in solid-state platforms their study has been largely limited by the constraints of linear-response probes and by finite momentum resolution. We propose to overcome these limitations by combining the spatial resolution of ultracold atomic systems with the nonlinear probing capabilities of two-dimensional spectroscopy (2DS). As a concrete illustration, we analyze momentum-resolved 2DS of the quantum sine-Gordon model describing the low-energy dynamics of two weakly coupled one-dimensional Bose-Einstein condensates. This approach reveals distinctive many-body signatures, most notably asymmetric cross-peaks reflecting the interplay between isolated (B_{2} breather) and continuum (B_{1} pair) modes. The protocol further enables direct characterization of anharmonicity and disorder, establishing momentum-resolved 2DS as both a powerful diagnostic for quantum simulators and a versatile probe of correlated quantum matter.
Source: Physical Review Letters
DOI: 10.1103/tfdm-qshs
Institutions: ETH Zurich, University of Palermo, TU Wien, University of Salerno
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,750
Awards: Strongly correlated Quantum Fields out of equilibrium, G2933676911, Continuous quantum measurements for many-body systems, Non-perturbative approaches to strongly correlated many-body systems, G6837300207, Realizing and probing quantum fields with ultra-cold atoms, G7452299184, G753033515, G8590477180, G985102149, G993971353
OpenAlex ID: W4415337841