Controlling unconventional properties of correlated materials by Fermi surface deformations and topological transitions
Lead Research Organisation:
King's College London
Department Name: Physics
Abstract
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People |
ORCID iD |
| Evgeny Kozik (Principal Investigator) |
Publications
Kim A
(2020)
Alleviating the sign problem in quantum Monte Carlo simulations of spin-orbit-coupled multiorbital Hubbard models
in Physical Review B
Kim A
(2020)
Multivaluedness of the Luttinger-Ward functional in the fermionic and bosonic system with replicas
in Physical Review B
Kim AJ
(2020)
Spin and Charge Correlations across the Metal-to-Insulator Crossover in the Half-Filled 2D Hubbard Model.
in Physical review letters
Kim AJ
(2021)
Homotopic Action: A Pathway to Convergent Diagrammatic Theories.
in Physical review letters
| Description | In the course of this project we have significantly advanced our ability to predict properties of strongly interacting electrons in solids. This was made possible by our development of new advanced approaches to correlated electrons, which enable theoretical studies with unprecedented and reliable accuracy in important regimes inaccessible before. The new theoretical framework has allowed us obtain a definitive solution of the longstanding problem of how insulating behaviour develops in a system of electrons in solids, where the proximity to the insulating state gives rise to intriguing phenomena of upmost technological importance, such as quantum magnetism and superconductivity. We have obtained precise experimentally verifiable predictions for physical observables, and brought crucial insights into the physical mechanisms at play, which could enable understanding and ultimately harnessing the high-temperature superconductivity for technological breakthroughs. We have also described with an a priori controlled accuracy how external conditions, such as pressure or chemical composition, affect the nature of the superconducting state at moderate interactions. These results bring us closer to understanding what mechanisms control characteristics of high-temperature superconductors, what parameters need to adjusted and how, which paves the way to putting superconductivity to practical use in widespread technologies. |
| Exploitation Route | Our new approach to solving systems of many interacting electrons opens new avenues for studies of some of the most intriguing macroscopic quantum effects in solids, which were not possible before. A wide of range of open questions and longstanding problems that have remained a challenge due to the inability to obtain reliable results could now be answered definitively. Further advances of theoretical methods based on the ideas formulated in this project have become possible and are now explored by our and other groups, which will bring us closer to achieving full control over properties of correlated materials for their practical application in technologies of the future. |
| Sectors | Aerospace Defence and Marine Creative Economy Digital/Communication/Information Technologies (including Software) Education Electronics Energy Manufacturing including Industrial Biotechology |
| Title | Extension of the local High Performance Computing facility |
| Description | This award allowed us to add six compute nodes to the local high performance computing (HPC) facility, extending its computing power by about 200 CPUs. The local HPC is crucial for development and testing of computational methods by the group, and enables large-scale calculations beyond the duration of this project. |
| Type Of Material | Improvements to research infrastructure |
| Year Produced | 2017 |
| Provided To Others? | Yes |
| Impact | All publications related to this project, as well as more recent work done after its completion, have been facilitated by the HPC facility. |
| Description | Sabbatical leave at and collaboration with University of Massachusetts Amherst, USA |
| Organisation | University of Massachusetts Amherst |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | We have brought our expertise and know-how in cutting-edge numeric techniques for correlated electron systems to the collaboration. |
| Collaborator Contribution | The host, the Precision Many-Body Physics Group at Umass Amherst, has contributed their world-class expertise and experience in accurate studies of correlated electron systems, as well as the desk space and facilities to perform the numeric calculations. |
| Impact | We have started and advanced several joint projects, which are at different stages of completion. Two papers are currently in preparation as a result of this collaboration visit. |
| Start Year | 2019 |
| Description | Sabbatical leave at and collaboration with University of Massachusetts Amherst, USA |
| Organisation | University of Massachusetts Amherst |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | We have brought our expertise and know-how in cutting-edge numeric techniques for correlated electron systems to the collaboration, which was key to the successful completion of the collaborative project. |
| Collaborator Contribution | The host, the Precision Many-Body Physics Group at Umass Amherst, has contributed their world-class expertise and experience in accurate studies of correlated electron systems, as well as the desk space and facilities to perform the numeric calculations. |
| Impact | Research paper: "Extended Crossover from a Fermi Liquid to a Quasiantiferromagnet in the Half-Filled 2D Hubbard Model", Fedor Šimkovic, IV, J. P. F. LeBlanc, Aaram J. Kim, Youjin Deng, N. V. Prokof'ev, B. V. Svistunov, and Evgeny Kozik Phys. Rev. Lett. 124, 017003 - Published 10 January 2020 |
| Start Year | 2018 |
| Title | Sigma DDMC technique in the strongly correlated regime |
| Description | We have developed a numerically exact method for the summation of irreducible Feynman diagrams for fermionic self-energy in the thermodynamic limit. The technique, based on the Diagrammatic Determinant Monte Carlo and its recent extension to connected diagrams, allows us to reach high (~10) orders of the weak-coupling expansion for the self-energy of the two-dimensional Hubbard model. Access to high orders reveals a non-trivial analytic structure of the self-energy and enables its controlled reconstruction with arbitrary momentum resolution in the nonperturbative regime of essentially strong correlations. The new approach enables calculation of electron properties with controlled accuracy in important regimes inaccessible by other methods. |
| Type Of Technology | New/Improved Technique/Technology |
| Year Produced | 2017 |
| Impact | The new method has been used in several publications to definitively solve longstanding problems in the area of correlated electrons. In particular, it allowed us to comprehensively understand the emergence of insulating behaviour from a metallic state of lattice electrons when the interactions are increased. The approach has influenced and stimulated further research on method development in our and other groups, contributing to the dramatic progress that the research on controlled methods for correlated electrons is seeing. |
| URL | https://journals.aps.org/prb/abstract/10.1103/PhysRevB.100.121102 |
| Description | Invited Condensed Matter Seminar, LMU, Munich, Germany, July 2017 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Invited talk: "Emergent BCS regime and pseudogap in the 2D Hubbard model" given by Evgeny Kozik. Sparked questions and discussions afterwards. |
| Year(s) Of Engagement Activity | 2017 |
| Description | Invited keynote talk at XXIX IUPAP Conference on Computational Physics (CCP2017), Paris, France, July 2017 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Invited keynote talk: "Towards controlled description of correlated fermions: Diagrammatic Monte Carlo for the Hubbard model" given by Evgeny Kozik. Sparked questions and discussions afterwards. |
| Year(s) Of Engagement Activity | 2017 |
| Description | Invited talk "Metal-insulator crossover in the 2d Hubbard model", Diagrammatic Monte Carlo workshop, CCQ Flatiron Institute, New York, July 2019. |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Invited talk titled "Metal-insulator crossover in the 2d Hubbard model", at the Diagrammatic Monte Carlo workshop, CCQ Flatiron Institute, New York, July 2019, given by Evgeny Kozik About 100 professional researches attended, the talked sparked questions and discussion afterwards. The talk has changed views on the problem. |
| Year(s) Of Engagement Activity | 2019 |
| URL | https://www.simonsfoundation.org/event/workshop-on-diagrammatic-monte-carlo/ |
| Description | Invited talk "Symmetry-restoring DiagMC: 2D Hubbard model" at the international Diagrammatic Monte Carlo workshop, held online hosted by the University of Massachusetts Amherst, March 2021 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Personal invitation to present the latest developments to a group of international experts. The talk fostered collaborations, the presented results became the foundation for new research in other international universities. |
| Year(s) Of Engagement Activity | 2021 |
| Description | Invited talk at CECAM Workshop: Greens function methods the next generation III, Toulouse, France, June 2017 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Invited talk: "Controlling Feynman Diagrammatic Expansions" by Evgeny Kozik. Sparked discussions and new research projects by several leading international groups. |
| Year(s) Of Engagement Activity | 2017 |
| Description | Invited talk at Diagrammatic Monte Carlo workshop, Simons Foundation, New York, USA, June 2017 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Invited talk "Dual fermions" by Evgeny Kozik. Sparked discussions, influenced research of several international research groups. |
| Year(s) Of Engagement Activity | 2017 |
| Description | Invited talk at Many-Electron Collaboration Meeting, Simons Foundation, New York, February 2019 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Invited talk " Controlled results for the strongly correlated regime of the 2d Hubbard model by diagrammatic Monte Carlo: insulator and non-Femi-liquid physics", Many Electron Collaboration Meeting, Simons Foundation, New York, February 2019, given by Evgeny Kozik. Sparked discussions. Resulted in offers of collaboration and follow up work. |
| Year(s) Of Engagement Activity | 2019 |
| Description | Invited talk at Simons Many Electron Collaboration Meeting, New York, USA, February 2018 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Invited talk: "Perturbation theory in non-perturbative regimes" given by Evgeny Kozik. Sparked questions and discussion afterwards. Helped establish close collaborations with world-leading international groups. |
| Year(s) Of Engagement Activity | 2017 |
| Description | Invited talk at Workshop on Correlated Electron Systems: Fermi Surface topological transitions and effects of spin-orbit coupling, Loughborough, December 2018 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Invited talk "High-order perturbation theory for correlated electrons", given at Workshop on Correlated Electron Systems: Fermi Surface topological transitions and effects of spin-orbit coupling, Loughborough, December 2018, given by Evgeny Kozik. Sparked questions and discussion afterwards. Lead to new ideas for collaboration. |
| Year(s) Of Engagement Activity | 2018 |
| Description | Invited talk at Workshop on Multicomponent and Strongly Correlated Superconductivity, NORDITA, Stockholm, August 2017 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Invited talk: "Superfluid states and physical nature of the pseudogap in the 2D Hubbard model" given by Evgeny Kozik. Sparked questions and discussion afterwards. International undergraduate students expressed interest in doing a PhD at King's. |
| Year(s) Of Engagement Activity | 2017 |
| Description | Keynote talk: "Diagrammatic Monte Carlo: the universal framework for precision quantum many-body physics" at International Conference on Computer Simulation in Physics and beyond, held online hosted by HSE Moscow, October, 2020 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Personal invitation to give a keynote talk at the International Conference on Computer Simulation in Physics and beyond, HSE Moscow, 14 October, 2020, given by Evgeny Kozik. The research stemming from this award was disseminated to a wide international audience, which sparked questions and discussion afterwards. |
| Year(s) Of Engagement Activity | 2020 |
| URL | https://www.youtube.com/watch?v=lnSrFbSf7pc&list=PLkRAeVdPqgMgMAbrIDpPrAJccaNo6S_1N&index=9&t=1490s&... |
| Description | contributed talk at 2018 APS March meeting, Los Angeles, March 2018 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Contributed talk "Determinant Diagrammatic Monte Carlo for the Self-Energy", at APS March Meeting 2018, Los Angeles, March 2018, given by Fedor Šimkovic, PhD student. Sparked discussions, helped foster collaborations, networking and improve student's visibility, ultimately helping him to secure a prestigious postdoctoral position |
| Year(s) Of Engagement Activity | 2018 |
| Description | contributed talk at 2018 APS March meeting, Los Angeles, March 2018 |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | contributed talk "Convergence Properties of Fully Dressed Diagrammatic Series and Pathologies of the Luttinger-Ward Functional", APS March Meeting 2018, Los Angeles, March 2018, given by Aaram Kim, PDRA on the project. Sparked discussions and interest to this research problem. Enabled the PDRA to engage in a new collaboration a complete a follow up study. |
| Year(s) Of Engagement Activity | 2018 |