Abstract
The demanding experimental access to the ultrafast dynamics of materials challenges our understanding of their electronic response to applied strong laser fields. For this purpose, trapped ultracold atoms with highly controllable potentials have become an enabling tool to describe phenomena in a scenario in which some effects are more easily accessible and 12 orders of magnitude slower. In this work, we introduce a mapping between the parameters of attoscience platforms and atomic cloud simulators and propose an experimental protocol to access the emission spectrum of high-harmonic generation, a regime that has so far been elusive to cold-atom simulation. As we illustrate, the benchmark offered by these simulators can provide new insights into the conversion efficiency of extended and short nuclear potentials, as well as the response to applied elliptical polarized fields or ultrashort few-cycle pulses.
- Received 28 August 2023
- Revised 14 November 2023
- Accepted 18 January 2024
DOI:https://doi.org/10.1103/PRXQuantum.5.010328
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
Published by the American Physical Society
Physics Subject Headings (PhySH)
Popular Summary
The ability to manipulate electron dynamics on its natural attosecond timescale has been closely related to the understanding of high-harmonic generation (HHG): a highly nonlinear phenomenon where a system absorbs many photons of the driving laser and emits a single photon of much higher energy. However, since these systems are difficult to analyze and calculate, some questions about their properties and dynamics remain. Here, we provide a blueprint for exploring some aspects of HHG by using ultracold atomic clouds.
Over the past two decades, neutral atoms controlled by laser fields have emerged as a promising platform for quantum simulation and computation. After early applications with condensed-matter problems, the fields of high-energy physics and quantum chemistry can now benefit from highly controllable devices that are effectively described by the same Hamiltonian of interest. Current efforts on the simulation of attosecond processes have accessed the regime where the energy imparted by the simulated laser field is strong enough to ionize the target atoms. However, the simulation of HHG remains fundamentally elusive when the incoming pulse is induced by shaken potentials. Using external electromagnetic gradients, here we propose an alternative strategy to access HHG and extract the associated emission yield. As an illustrative example, we show how the duration and ellipticity of the incoming field affects the efficiency of HHG in these simulators. We also present details on the experimental parameters that can simulate specific atomic targets and discuss the main sources of errors, which we numerically evaluate.
Our approach to simulating high-harmonic phenomena can also be extended to other, more exotic configurations. For example, considering extended potentials or periodic traps, one could benchmark the predictive power of conventional numerical methods beyond the demanding control and tunability offered by real materials.
