Orbit-Based Methods for Multielectron Systems in Strong Fields
Lead Research Organisation:
Lancaster University
Department Name: Physics
Abstract
Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.
People |
ORCID iD |
| Henning Schomerus (Principal Investigator) |
Publications
Bellec M
(2020)
Observation of supersymmetric pseudo-Landau levels in strained microwave graphene.
in Light, science & applications
Keil R
(2016)
Universal Sign Control of Coupling in Tight-Binding Lattices.
in Physical review letters
Lai X
(2015)
Influence of the Coulomb potential on above-threshold ionization: A quantum-orbit analysis beyond the strong-field approximation
in Physical Review A
Malzard S
(2015)
Topologically Protected Defect States in Open Photonic Systems with Non-Hermitian Charge-Conjugation and Parity-Time Symmetry.
in Physical review letters
Poli C
(2014)
Degeneracy doubling and sublattice polarization in strain-induced pseudo-Landau levels
in Physical Review B
Poli C
(2015)
Selective enhancement of topologically induced interface states in a dielectric resonator chain.
in Nature communications
Schomerus H
(2014)
Non-Hermitian-transport effects in coupled-resonator optical waveguides
in Physical Review A
Weich T
(2014)
Formation and interaction of resonance chains in the open three-disk system
in New Journal of Physics
| Description | Main achievements Theory/Methodology In the course of the project, which also involved researchers at UCL and Leeds, we have successfully implemented and modified quantum-mechanical and semiclassical initial value representations (IVRs) in order to describe one-electron systems in one and three dimensions in strong fields. Examples of such approaches are the Coupled Coherent States method and the Herman Kluk propagator. We have focused on high-order harmonic generation and strong-field ionization (see Zagoya et al, New J. Phys. 16, 103040 (2014); C. Symonds, et al, Phys. Rev. A 91, 023427 (2015)). Thereby, we faced the following challenges, which were not trivial to overcome: (a) Typically, IVRs are applied in quantum chemistry, for which the electronic wave packet is initially in the continuum, while in strong-field physics it is initially bound. How to treat ionization and in particular tunnelling using such methods has been the target of considerable debate in the semiclassical community. (b) High-order harmonic generation is a coherent process building up close to the core over at least a few cycles of the driving field. Hence, apart from the problems of how to treat an initially bound wave packet with IVRs, there is the issue that these approaches degrade over many cycles of the field. We have solved problems (a) and (b) by showing that there is transmission near the potential barrier and using a reprojection technique in the CCS method to correct for this degradation. The outcome of the IVRS exhibits an excellent agreement with more standard methods such as the solution of the time-dependent Schrodinger equation (TDSE) in a grid. The semi-analytical strong-field method developed by us, which was called the Coulomb Quantum-Orbit Strong-Field Approximation (CQSFA) was successfully employed to compute and analyze above-threshold ionization spectra (X. Lai, et al, Phys. Rev. A 92, 043407 (2015)) and, more recently, near-threshold fan-shaped interference structures that occur in photoelectron momentum distributions and cannot be reproduced using more established strong-field methods such as the Strong-Field Appproximation (SFA; see Lai et al, arXiv:1703.04123). We have provided a unique explanation for this effect as a holographic pattern formed by the interference of direct electron trajectories with those deflected by the residual Coulomb potential. In comparison to existing Coulomb-corrected approaches, the developed method can be applied to all scattering angles and leads to fewer cusps in the near-threshold region. Furthermore, while standard methods require a few million orbits, we are able to produce converged results with three. We are currently performing a detailed analysis of near-threshold interference patterns in Above-threshold Ionization (ATI) using the Herman Kluk propagator and the CQSFA, and a publication is in preparation. This, together with the research below, has prepared the ground for studying two-electron systems using the CQSFA, which will be done in the next few months. Applications Laser-Induced Nonsequential Double Ionization: Simultaneously, we have investigated interference in correlated two-electron systems using the SFA, in the context of recollision-excitation with subsequent ionization (RESI). In this case, an electron is freed by tunnel ionization, propagates in the continuum and it is driven back by the field towards its parent ion. This recollision promotes a second electron to an excited state, from which it subsequently tunnels. We have provided theoretical evidence that quantum interference in RESI is much more robust than previously expected, and may survive integration over many degrees of freedom and even focal averaging (A. Maxwell and C. Faria, Phys. Rev. A 92, 023421 (2015) and Phys. Rev. Lett. 116, 143001 (2016)). This interference stems from different events and from several intermediate channels. These effects may be controlled by an appropriate pulse choice. In order to explain current experiments (M. Kubel et al., New J. Phys. 16, 033008 (2014)), however, we had to introduce ad hoc phases and amplitudes to account for the absence of the Coulomb potential. Since, formally, the second electron can be described in the same way as ATI, we are ready to apply the CQSFA to this problem and develop a more rigorous approach. Plasmonically enhanced HHG: Recently, it has been suggested that plasmonic enhancements in systems such as nanostructures may enhance the HHG conversion efficiency and maximal harmonic order in several orders of magnitude. With this aim in mind, and taking into account that spatially inhomogeneous fields are potentially a good testing ground for our methods, we have used the TDSE, classical-trajectory methods and analytical models to investigate such systems in reduced-dimensionality models with effective potentials employed in the literature. We have shown that the features encountered can be explained using Mathieu's equation, so that the wave packet in the strong field can be loosely viewed as an ensemble of classical particles in a radio-frequency trap (C. Zagoya, et al, Phys. Rev. A 93, 053419 (2016)). This work, however, has called into question the present simplified models and shown that a full macroscopic description of the problem will be necessary. We are currently in a good position to deal with this problem, as we have also worked on the macroscopic propagation of HHG. HHG propagation: In collaboration with Prof. Marangos's group at the Imperial College London, we have investigated the macroscopic response of HHG, with the aim of steering the motion of an electron using orthogonally polarized laser fields. We have shown that appropriate propagation conditions can suppress or enhance particular electron orbits, and thus be used to extract and control the angle with which an electron returns to its parent ion (T. Das, et al, Phys. Rev. A 92, 023406 (2015)). We intend to investigate propagation in other media and propagation geometries. |
| Exploitation Route | This project combines methodological and conceptual progress which can be applied to a wide range of atomic and molecular systems. These concepts can prove useful to advance the understanding and control of chemical reactions, in particular in approaches that exploit nonequilibrium short-time scale physics. |
| Sectors | Electronics,Energy |
| Title | Data for "Nonlinear mode competition and symmetry-protected power oscillations in topological lasers" |
| Description | Data for "Nonlinear mode competition and symmetry-protected power oscillations in topological lasers" |
| Type Of Material | Database/Collection of data |
| Year Produced | 2018 |
| Provided To Others? | Yes |
| Impact | Research paper published, doi 10.1088/1367-2630/aac9e0 |
| URL | http://www.research.lancs.ac.uk/portal/en/datasets/data-for-nonlinear-mode-competition-and-symmetryp... |
| Title | dataset CQSFA |
| Description | Numerical data on coulomb-corrected strong field approximation for hydrogen |
| Type Of Material | Database/Collection of data |
| Provided To Others? | No |
| Impact | DOI: 10.1103/PhysRevA.92.043407 |
| URL | http://dx.doi.org/10.17635/lancaster/researchdata/8 |
| Title | dataset CROW |
| Description | Numerical data on defect states in nonhermitian systems - CROW consisting of asymmetric open resonators. Produced by python and matlab. |
| Type Of Material | Database/Collection of data |
| Provided To Others? | No |
| Impact | DOI: 10.1103/PhysRevLett.115.200402 |
| URL | http://dx.doi.org/10.17635/lancaster/researchdata/23 |
| Title | dataset semichiral Lieb |
| Description | Numerical data for disordered Lieb lattices with partial chiral symmetry |
| Type Of Material | Database/Collection of data |
| Provided To Others? | No |
| Impact | doi:10.1088/2053-1583/aa56de |
| Description | Faria, Lai |
| Organisation | German Academy of Sciences |
| Country | Germany |
| Sector | Academic/University |
| PI Contribution | Provided semiclassical description of ionization in hydrogen. |
| Collaborator Contribution | Provided numerical description of ionization in hydrogen. |
| Impact | doi 10.1103/PhysRevA.92.043407 |
| Start Year | 2012 |
| Description | Faria, Lai |
| Organisation | University College London |
| Department | Department of Physics & Astronomy |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | Provided semiclassical description of ionization in hydrogen. |
| Collaborator Contribution | Provided numerical description of ionization in hydrogen. |
| Impact | doi 10.1103/PhysRevA.92.043407 |
| Start Year | 2012 |
| Description | Nice |
| Organisation | University of Nice Sophia-Antipolis |
| Country | France |
| Sector | Academic/University |
| PI Contribution | Semiclassical description, modelling of structures for wave scattering experiments |
| Collaborator Contribution | Numerical modelling, experiments |
| Impact | doi:10.1088/1367-2630/16/3/033029 DOI: 10.1038/ncomms7710 |
| Start Year | 2013 |
| Description | Wiersig |
| Organisation | The Otto-von-Guericke University Magdeburg |
| Department | Institute of Theoretical Physics |
| Country | Germany |
| Sector | Academic/University |
| PI Contribution | Theory for wave propagation under losses |
| Collaborator Contribution | Numerical modelling |
| Impact | doi 10.1103/PhysRevA.90.053819 |
| Description | Controlling photonic systems via topological anomalies, Conference "META 2019", 24 July 2019, Lisbon, Portuga |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Talk on topological photonics |
| Year(s) Of Engagement Activity | 2019 |
| Description | International Workshop on "Asymmetric Microcavity and Wave Chaos", 21 March 2017, Beijing, China |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Topological states from exceptional points-exceptional points from topological states, International Workshop on "Asymmetric Microcavity and Wave Chaos", 21 March 2017, Beijing, China |
| Year(s) Of Engagement Activity | 2017 |
| Description | Mode selection by symmetry and topology, Conference "Journées de la Matière Condensée - JMC15", 25 August 2016, Bordeaux, France |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Mode selection by symmetry and topology, Conference "Journées de la Matière Condensée - JMC15", 25 August 2016, Bordeaux, France |
| Year(s) Of Engagement Activity | 2016 |
| Description | Photonic Topological Anomalies, 10 October 2019, Cambridge, UK |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Postgraduate students |
| Results and Impact | Talk on topological photonics |
| Year(s) Of Engagement Activity | 2019 |
| Description | Photonic Topological Anomalies, NORDITA program "Topological Quantum Matter: From Low-Temperature Physics to Non-Equilibrium Dynamics", 8 August 2019, Stockholm, Sweden |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Talk on topological photonics |
| Year(s) Of Engagement Activity | 2019 |
| Description | Photonic systems with topological anomalies, 25 April 2019, Lund, Sweden |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Professional Practitioners |
| Results and Impact | Talk on topological photonic systems |
| Year(s) Of Engagement Activity | 2019 |
| Description | Polarization anomaly in photonic discrete-time quantum walks, 11 April 2019, Stockholm, Sweden |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Professional Practitioners |
| Results and Impact | Talk on topological photonic systems |
| Year(s) Of Engagement Activity | 2019 |
| Description | Selective amplification and charge conjugation in topological photonics, 5 August 2016, Nanjing, China |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Professional Practitioners |
| Results and Impact | Selective amplification and charge conjugation in topological photonics, 5 August 2016, Nanjing, China |
| Year(s) Of Engagement Activity | 2016 |
| Description | Selective amplification of semi-chiral defect states, 28 July 2016, META 2016, Malaga, Spain |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Selective amplification of semi-chiral defect states, 28 July 2016, META 2016, Malaga, Spain |
| Year(s) Of Engagement Activity | 2016 |
| Description | Summer school "Stochastic processes and random matrices" |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Type Of Presentation | keynote/invited speaker |
| Geographic Reach | International |
| Primary Audience | Postgraduate students |
| Results and Impact | discussions with participating students and fellow lecturers |
| Year(s) Of Engagement Activity | 2015 |
| Description | The role of charge conjugation symmetry in topological photonics, 16 June 2016, Heraklion, Greece |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | The role of charge conjugation symmetry in topological photonics, 16 June 2016, Heraklion, Greece |
| Year(s) Of Engagement Activity | 2016 |
| Description | The role of charge conjugation symmetry in topological photonics, 8 August 2016, PIERS 2016, Shanghai, China |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | The role of charge conjugation symmetry in topological photonics, 8 August 2016, PIERS 2016, Shanghai, China |
| Year(s) Of Engagement Activity | 2016 |
| Description | Topological effects in active media, "Central European Workshop on Quantum Optics (CEWQO)", 3 June 2019, Paderborn, Germany |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Talk on topological photonics |
| Year(s) Of Engagement Activity | 2019 |
| Description | Topological lasers and condensates, 13 March 2019, Imperial College London, UK |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Professional Practitioners |
| Results and Impact | Talk on a wide range of theoretical concepts and their experimental implementation based on EPSRC funded resear |
| Year(s) Of Engagement Activity | 2019 |
| Description | Topological mode selection and photonic anomalies in lasers and condensates, 8 July 2019, RIKEN, Wako-shi, Japan |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Professional Practitioners |
| Results and Impact | Talk on topological photonics |
| Year(s) Of Engagement Activity | 2019 |
| Description | Topological mode selection, "Waves Côte d'Azur", 7 June 2019, Nice, France |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Talk on topological photonics |
| Year(s) Of Engagement Activity | 2019 |
| Description | Topological photonic anomalies, 24 June 2019, KAIST, Daejeon, Republic of Korea |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Postgraduate students |
| Results and Impact | Talkon topological photonics |
| Year(s) Of Engagement Activity | 2019 |
| Description | Topological protection and quantum noise in nonlinear photonic systems, Conference "META 2019", 25 July 2019, Lisbon, Portugal |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Talk on topological photonics |
| Year(s) Of Engagement Activity | 2019 |
| Description | talk Exeter |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Other academic audiences (collaborators, peers etc.) |
| Results and Impact | discussion of new research direction |
| Year(s) Of Engagement Activity | 2015 |
| Description | talk FU Berlin |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Other academic audiences (collaborators, peers etc.) |
| Results and Impact | discussions on research topic |
| Year(s) Of Engagement Activity | 2015 |
| Description | talk Illmenau |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Other academic audiences (collaborators, peers etc.) |
| Results and Impact | discussions about research topic |
| Year(s) Of Engagement Activity | 2015 |
| Description | talk Magdeburg |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Other academic audiences (collaborators, peers etc.) |
| Results and Impact | discussions on research topic |
| Year(s) Of Engagement Activity | 2015 |
| Description | talk Paderborn |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Professional Practitioners |
| Results and Impact | Talk Paderborn |
| Year(s) Of Engagement Activity | 2015 |
| Description | talk TU Berlin |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Other academic audiences (collaborators, peers etc.) |
| Results and Impact | discussions on research topic |
| Year(s) Of Engagement Activity | 2015 |
| Description | talk at International Workshop on Advances in Quantum Chaotic Scattering: From (Non-)Linear Waves to Few-Body Systems |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Type Of Presentation | keynote/invited speaker |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Discussions about wave phenomena also related to atomic physics, in wider context of conference Follow-up invitations (eg Heidelberg 2014) |
| Year(s) Of Engagement Activity | 2013 |
| Description | talk at Gathering on "Random matrix theory, correlations and long tail distributions" |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Type Of Presentation | keynote/invited speaker |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | discussions |
| Year(s) Of Engagement Activity | 2015 |
| Description | talk at LMS joint research group meeting |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Type Of Presentation | keynote/invited speaker |
| Geographic Reach | National |
| Primary Audience | Professional Practitioners |
| Results and Impact | discussions about possible further research |
| Year(s) Of Engagement Activity | 2015 |
| Description | talk at LPHYS 2014 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Type Of Presentation | keynote/invited speaker |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | discussions resulting in new project |
| Year(s) Of Engagement Activity | 2014 |
| Description | talk at META 2015 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Type Of Presentation | keynote/invited speaker |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | new collaborations |
| Year(s) Of Engagement Activity | 2015 |
| Description | talk at Symposium on "Quantum Chaos, Billards, RMT and more" in honor of Hans-Jürgen Stöckmann on his 70th birthday |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Type Of Presentation | keynote/invited speaker |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | discussions, follow-up invitations, exploration of collaborations |
| Year(s) Of Engagement Activity | 2015 |
| Description | workshop "Gaussian ensembles and their experimental realization", 18 May 2017, Nice, France |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Nonhermitian antilinear symmetries, workshop "Gaussian ensembles and their experimental realization", 18 May 2017, Nice, France |
| Year(s) Of Engagement Activity | 2017 |