Article
Physics, Multidisciplinary
Wu Wang, Jie Zhou, Boqun Liu, Xu Wang
Summary: A new approach to excite the isomeric Th-229 nuclear state is proposed, using laser-driven electron recollision process which does not require precise knowledge of the energy of the isomeric state. The well timed excitation can be exploited to control the coherence of the isomeric state, with experimental realization within reach using tabletop laser systems.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Yuxing Bai, Xiaolei Hao, Weidong Li, Jing Chen
Summary: In the above-threshold ionization spectrum, we theoretically identify a two-cutoff structure in the recollision energy distribution, with the second cutoff induced by the acceleration of the Coulomb field. This second cutoff affects the photoelectron momentum spectrum and the differential cross-sections in the laser-induced electron diffraction scheme.
RESULTS IN PHYSICS
(2022)
Article
Physics, Multidisciplinary
Frieder Lindel, Edoardo G. Carnio, Stefan Yoshi Buhmann, Andreas Buchleitner
Summary: We adjust the quantum statistics of a bosonic field to deterministically manipulate a quantum system into a desired state. Accessible states of the field in experiments enable precise control of multilevel or multiqubit systems, even beyond the limitations of rotating-wave approximation. This extends optimal control theory to the domain of fully quantized and strongly coupled control and target degrees of freedom.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Yu-Ning Yang, Su-Qi Chen, Zhao-Han Zhang, Hui Jiang, Min Chen, Yang Li, Feng He
Summary: This paper builds a model to explain the high harmonic generation in combined EUV and midinfrared laser fields. By embodying the spin-resolved three-electron dynamics, the model results agree with the time-dependent Schrodinger equation simulations including three active electrons. The intriguing picture explored in this work is fundamentally distinguished from scenarios relying on spin-orbit coupling.
PHYSICAL REVIEW LETTERS
(2023)
Article
Optics
Zhangjin Chen, Qiongmin Ding, Qinghua Chen, Shuqi Li, Fang Liu, Huipeng Kang, Toru Morishita, Jing Chen
Summary: We simulated the two-dimensional high-energy photoelectron momentum distributions (PMDs) for high-order above threshold ionization (HATI) in intense elliptically polarized laser fields. By analyzing the center shift of the measured PMDs in elliptically polarized fields, the recollision time can be identified.
Article
Optics
L. Kelley, Z. Germain, E. C. Jones, D. Milliken, Barry C. Walker
Summary: This study addresses the challenge of finding the optimal laser intensity and wavelength to achieve high-energy, strong field rescattering, and reports maximum yields of hole creation in both K-shell and L-I shell. The results show a simple scaling of peak rescattering with atomic number and laser wavelength, suggesting a possibility to describe ideal laser parameters for general high-energy laser rescattering processes.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2021)
Article
Physics, Nuclear
Xu Wang
Summary: This article elaborates on a new method for exciting the (229)Th nucleus using laser-driven electron recollision. The method has been improved by adopting recently calculated electronic excitation cross sections, which show significantly higher values than the previously used cross sections. With the updated cross sections, the probability of isomeric excitation of (229)Th from electron recollision is calculated to be on the order of 10^(-12) per nucleus per femtosecond laser pulse. The article also analyzes the dependence of the excitation probability on various laser parameters such as intensity, wavelength, and pulse duration.
Article
Physics, Applied
Maxim Shugaev, Leonid Zhigilei
Summary: This study demonstrates that under nonablative thermoelastic irradiation regime, laser pulses with appropriate spot size and energy deposition depth can generate high-intensity surface acoustic waves (SAWs) in Si, with strain amplitudes reaching levels of 10^-4 to 10^-3. These strong SAWs have the potential to drive nonlinear profile sharpening and shock front formation during their propagation, presenting the feasibility of continuous generation of strong nonlinear pulses of SAWs for various applications.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Optics
Jie Su, Zichao Liu, Jianying Liao, Xuefei Huang, Yingbin Li, Cheng Huang
Summary: The study investigates the nonsequential double ionization of Argon atoms in counter-rotating two-color elliptically polarized fields using a three-dimensional classical model. The results show that as the relative phase between the two elliptical fields increases, the return angle of the electrons decreases and the behavior of the electron pairs shifts from anti-correlation to correlation.
Article
Physics, Multidisciplinary
Zhiqiang Wang, Wei Quan, Xiaolei Hao, Jing Chen, Xiaojun Liu
Summary: In this study, we investigate the effect of the ellipticity on the excitation and ionization of noble gas atoms in strong laser fields. We use a semiclassical model to analyze the results at different intensities and wavelengths, considering or ignoring the nonadiabatic effect. Our findings reveal that the ratio between excitation and ionization yields shows an anomalous maximum at nonzero ellipticity when nonadiabatic effect is ignored, but this anomalous behavior disappears when nonadiabatic effect is considered. This can be attributed to the nonadiabatic corrections of instantaneous ionization rate and the initial photoelectron momentum distribution at the tunnel exit.
FRONTIERS IN PHYSICS
(2023)
Article
Physics, Condensed Matter
Pardeep Kumar, Thakshila M. Herath, Vadym Apalkov
Summary: In this study, we theoretically investigate the interaction between an ultrastrong femtosecond-long linearly polarized optical pulse and AB-stacked bilayer graphene. The angle of incidence of the pulse can manipulate the generation of current and its direction, and the symmetry of BLG affects these processes.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Article
Optics
Tian Sun, Lei Zhao, Yang Liu, Jing Guo, Hang Lv, Haifeng Xu
Summary: In this study, the Rydberg state excitation (RSE) process of H2 molecules induced by a strong laser field in the tunneling ionization region was investigated experimentally. Both neutral parent molecules H2 and fragment atoms H were observed to survive in high Rydberg states under the influence of strong 800-nm femtosecond laser fields, but their behaviors differed significantly with varying laser intensity and ellipticity. The results were compared with single and double ionization as well as RSE from the companion atom Ar. Analysis indicated that the H2 RSE was produced by the recapture or frustrated tunneling ionization process, and the nonsequential double ionization of H2 induced by recollision of the tunneled electrons played an important role in the fragment H RSE of H2 in strong laser fields.
Article
Physics, Multidisciplinary
Yan-Fei Li, Yue-Yue Chen, Karen Z. Hatsagortsyan, Christoph H. Keitel
Summary: This study investigates the longitudinal polarization of an electron beam during the interaction with counterpropagating circularly polarized ultraintense laser pulses, taking into account the anomalous magnetic moment of the electron. It is found that despite the suppression of helicity transfer from laser photons to the electron beam in linear and nonlinear Compton scattering processes, helicity transfer can still occur through an intermediate step of electron radiative transverse polarization, followed by spin rotation induced by the anomalous magnetic moment of the electron. Monte Carlo simulations demonstrate the consequent helicity transfer and electron radial polarization in femtosecond timescale. The findings highlight the importance of the leading QED vertex correction to the electron anomalous magnetic moment in the polarization dynamics in ultrastrong laser fields.
PHYSICAL REVIEW LETTERS
(2022)
Article
Optics
Peipei Xin, Tianhui Qiu, Hongyang Ma, Hua Yuan, Hongping Liu
Summary: This study investigates the photoionization dynamics of bounded electrons in different energy states of a hydrogen atom using ultrashort near-infrared laser pulses. The spectral characteristics and ionization probabilities of the different states are found to differ significantly. Comparing the momentum spectrum and angular distributions of low-energy photoelectrons reveals differences in the long-range Coulomb attraction force between the states. The analysis of photoelectron spectroscopy identifies the parity characteristics of photoelectrons in different energy intervals and their corresponding ionization processes. The momentum distributions of electrons ionized by laser pulses with different profiles are also presented, highlighting the importance of the carrier-envelope phase in determining the rotating structure of the emission spectrum.
Article
Optics
Hongqiang Xie, Hongbin Lei, Guihua Li, Jinping Yao, Qian Zhang, Xiaowei Wang, Jing Zhao, Zhiming Chen, Ya Cheng, Zengxiu Zhao
Summary: This study investigates the quantum emission properties of molecular ions, finding that collective emission behaviors can be readily observed in high-gain cases, while superradiant amplification is quenched in low-gain cases. Seed amplification and free induction decay play essential roles in the latter situation.
PHOTONICS RESEARCH
(2021)
Article
Optics
S. Popruzhenko, T. A. Lomonosova
Summary: The theory formulates a semiclassical analytic approach to describe the excitation of atomic Rydberg states by intense laser radiation in the multiphoton limit of ionization. By separating the electron motion in the laser field and Coulomb field of the nucleus, it allows for the calculation of classical cut-off positions in the distribution of excited atoms in principal and orbital quantum numbers, and the identification of the effects of quantum interference.
LASER PHYSICS LETTERS
(2021)
Article
Chemistry, Physical
Dominik Sidler, Michael Ruggenthaler, Christian Schaefer, Enrico Ronca, Angel Rubio
Summary: This article provides a brief introduction to the theoretical complexity of polaritonic chemistry and emphasizes the importance of ab initio methods. It proposes novel ideas and research avenues regarding quantum collectivity and resonance phenomena in reaction rates under vibrational strong coupling. A computationally efficient Langevin framework based on quantum electrodynamical density-functional theory is also suggested, revealing cavity-induced non-equilibrium nuclear dynamics. Overall, the latest ab initio results suggest a paradigmatic shift in the understanding of ground-state chemical reactions under vibrational strong coupling.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Physics, Multidisciplinary
S. Popruzhenko, D. Tyurin
Summary: This study examines the ionization process in intense electromagnetic fields using quantum orbits, investigating the concept of ionization time and electron escape probability from barriers under high electric field strengths. The research shows that the common conjecture holds true under certain conditions, but a small non-adiabatic time shift occurs for laser pulses of arbitrary shape.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Article
Chemistry, Physical
Davis M. Welakuh, Johannes Flick, Michael Ruggenthaler, Heiko Appel, Angel Rubio
Summary: Recent progress in quantum-optical experiments enables the modification and control of chemical and physical properties of atoms, molecules, and solids by strongly coupling to the quantized field. This study extends the Sternheimer approach to efficiently compute excited-state properties of strongly coupled light-matter systems within the framework of quantum electrodynamical density-functional theory. The method captures the features of strong light-matter coupling and provides an alternative approach for computing excited-state properties of large molecular systems interacting with the quantized electromagnetic field.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
News Item
Optics
Dieter Bauer
Review
Chemistry, Physical
Markus Penz, Erik I. Tellgren, Mihaly A. Csirik, Michael Ruggenthaler, Andre Laestadius
Summary: The Hohenberg-Kohn theorem is considered the conceptual basis of density functional theory, allowing for a full characterization of an electronic system's ground state using only its one-body particle density. This review clarifies the status of the Hohenberg-Kohn theorem and explores extensions of the theory that include magnetic fields. The findings suggest that the Hohenberg-Kohn theorem is not the fundamental basis of density functional theory, but rather a consequence of a more comprehensive mathematical framework. These results are particularly important for the development of generalized density functional theories.
ACS PHYSICAL CHEMISTRY AU
(2023)
Review
Chemistry, Multidisciplinary
Michael Ruggenthaler, Dominik Sidler, Angel Rubio
Summary: This review presents the theoretical foundations and first-principles frameworks to describe quantum matter within quantum electrodynamics (QED) in the low-energy regime, with a focus on polaritonic chemistry. Starting from fundamental physical and mathematical principles, the review explores the ab initio nonrelativistic QED and its applications in approximative computational methods. The benefits of these methods in understanding photon-induced changes of chemical properties and reactions are highlighted, and open theoretical questions in polaritonic chemistry are identified.
Article
Chemistry, Physical
Thomas Schnappinger, Dominik Sidler, Michael Ruggenthaler, Angel Rubio, Markus Kowalewski
Summary: Experimental studies have shown that optical cavities can influence chemical reactions through strong coupling between vibrational or electronic modes and quantized cavity modes. However, the understanding of the interaction between molecules and confined light modes is currently incomplete. In this study, we present a theoretical model that considers intermolecular interactions and accurately describes strongly coupled molecular ensembles with an optical cavity. Our results demonstrate the importance of cavity-mediated dipole-dipole interactions in energetic changes of individual molecules in the coupled ensemble.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Review
Chemistry, Physical
Markus Penz, Erik I. Tellgren, Mihaily A. Csirik, Michael Ruggenthaler, Andre Laestadius
Summary: The Hohenberg-Kohn theorem is the conceptual basis for density functional theory, which characterizes the ground state of an electronic system using only the one-body particle density. This article discusses the status of this theorem in different extensions of DFT, including magnetic fields. Current-density-functional theory (CDFT) is examined and various formulations known in the literature are reviewed. The article also explores the implications of Maxwell-Schro''dinger DFT and quantum-electrodynamic DFT.
ACS PHYSICAL CHEMISTRY AU
(2023)
Article
Optics
Lina Bielke, Christoph Juerss, Vincent Burgtorf, Dieter Bauer
Summary: In frequently studied two-band models for solid-state high-order harmonic generation, the wavelength range of interband harmonics can theoretically extend from the minimum to the maximum band gap. However, there is a laser-intensity-dependent cutoff that may occur at a lower energy level than the maximum band gap, unless the laser intensity is high enough for electrons to explore the entire Brillouin zone. This cutoff is formed by destructive interference of electron emissions from different initial states in the Brillouin zone. Our findings, based on calculations for Su-Schrieffer-Heeger chains, are applicable to other two-band systems as well. The completeness of destructive interference and formation of the cutoff depend on the fine sampling of the Brillouin zone or the sufficient length of the finite chain in position space.
Article
Materials Science, Multidisciplinary
Christoph Juerss, Dieter Bauer
Summary: Edge states play an important role in the electron dynamics of two-dimensional topological insulators. This work compares the numerically simulated high-harmonic generation in the bulk of the Haldane model to the generation in finite flakes with edge states, explaining the differences. The results show that peaks for energies below the bulk band gap appear in the spectra of finite flakes, with the positions of these peaks depending strongly on the size of the flakes.
Article
Materials Science, Multidisciplinary
Vasil Rokaj, Markus Penz, Michael A. Sentef, Michael Ruggenthaler, Angel Rubio
Summary: In this paper, a translationally invariant framework called quantum-electrodynamical Bloch (QED-Bloch) theory is introduced to describe the behavior of periodic materials in a homogeneous magnetic field and their strong coupling to the quantized photon field. The theory predicts the existence of fractal polaritonic spectra and reveals how a terahertz cavity can modify the standard Hofstadter butterfly. When the quantized photon field is absent, the QED-Bloch theory captures the well-known fractal spectrum of the Hofstadter butterfly and can be used to describe the behavior of two-dimensional materials in strong magnetic fields. The paper also explores the effect of cavity confinement on Landau levels and finds that the cavity alters the quantized Hall conductance and modifies the Hall plateaus.
Article
Physics, Multidisciplinary
Vasil Rokaj, Michael Ruggenthaler, Florian G. Eich, Angel Rubio
Summary: Cavity modification of material properties and phenomena is a novel research field mainly driven by the advancements in strong light-matter interactions. Despite the progress made, exact solutions for extended systems strongly coupled to the photon field are currently unavailable, and current theories and experiments rely heavily on finite-system models. In this study, the authors revisit Sommerfeld's theory of the free electron gas in cavity quantum electrodynamics and analytically solve the system in the long-wavelength limit for a general number of noninteracting electrons. They demonstrate that the ground state of the electron-photon system is a Fermi liquid containing virtual photons. Additionally, they show the modifications induced by the cavity field on plasmon-polariton excitations, optical conductivity, and DC conductivity of the electron gas.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Multidisciplinary Sciences
Christian Schaefer, Florian Buchholz, Markus Penz, Michael Ruggenthaler, Angel Rubio
Summary: This work presents a nonperturbative formulation of quantum electrodynamics in the long-wavelength limit without considering photons, providing an accurate starting point for ab initio methods with the potential to increase accuracy. The formulation takes into account the quantized nature of light while remaining computationally simple enough for a wide range of applications.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Physics, Multidisciplinary
Davis M. Welakuh, Michael Ruggenthaler, Mary-Leena M. Tchenkoue, Heiko Appel, Angel Rubio
Summary: This study highlights the alternative approach of ab initio simulations of coupled light-matter systems to enhance the performance of photon sources. By treating light and matter equally, it is discovered that pathways for down-conversion processes can be created and enhanced, leading to increased efficiency and nonclassicality of the photon source.
PHYSICAL REVIEW RESEARCH
(2021)
