Geometry of Krylov complexity
We develop a geometric approach to operator growth and Krylov complexity in many-body quantum systems governed by symmetries. We start by showing a direct link between a unitary evolution with the Liouvillian and the displacement operator of appropriate generalized coherent states. This connection m...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
American Physical Society
2022-01-01
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| Series: | Physical Review Research |
| Online Access: | http://doi.org/10.1103/PhysRevResearch.4.013041 |
| _version_ | 1827285568509181952 |
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| author | Pawel Caputa Javier M. Magan Dimitrios Patramanis |
| author_facet | Pawel Caputa Javier M. Magan Dimitrios Patramanis |
| author_sort | Pawel Caputa |
| collection | DOAJ |
| description | We develop a geometric approach to operator growth and Krylov complexity in many-body quantum systems governed by symmetries. We start by showing a direct link between a unitary evolution with the Liouvillian and the displacement operator of appropriate generalized coherent states. This connection maps operator growth to a purely classical motion in phase space. The phase spaces are endowed with a natural information metric. We show that, in this geometry, operator growth is represented by geodesics, and Krylov complexity is proportional to a volume. This geometric perspective also provides two novel avenues toward computation of Lanczos coefficients, and it sheds new light on the origin of their maximal growth. We describe the general idea and analyze it in explicit examples, among which we reproduce known results from the Sachdev-Ye-Kitaev model, derive operator growth based on SU(2) and Heisenberg-Weyl symmetries, and generalize the discussion to conformal field theories. Finally, we use techniques from quantum optics to study operator evolution with quantum information tools such as entanglement and Renyi entropies, negativity, fidelity, relative entropy, and capacity of entanglement. |
| first_indexed | 2024-04-24T10:16:59Z |
| format | Article |
| id | doaj.art-1c8ef1f140754ab3a0952f0c0ee962f6 |
| institution | Directory Open Access Journal |
| issn | 2643-1564 |
| language | English |
| last_indexed | 2024-04-24T10:16:59Z |
| publishDate | 2022-01-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Research |
| spelling | doaj.art-1c8ef1f140754ab3a0952f0c0ee962f62024-04-12T17:17:16ZengAmerican Physical SocietyPhysical Review Research2643-15642022-01-014101304110.1103/PhysRevResearch.4.013041Geometry of Krylov complexityPawel CaputaJavier M. MaganDimitrios PatramanisWe develop a geometric approach to operator growth and Krylov complexity in many-body quantum systems governed by symmetries. We start by showing a direct link between a unitary evolution with the Liouvillian and the displacement operator of appropriate generalized coherent states. This connection maps operator growth to a purely classical motion in phase space. The phase spaces are endowed with a natural information metric. We show that, in this geometry, operator growth is represented by geodesics, and Krylov complexity is proportional to a volume. This geometric perspective also provides two novel avenues toward computation of Lanczos coefficients, and it sheds new light on the origin of their maximal growth. We describe the general idea and analyze it in explicit examples, among which we reproduce known results from the Sachdev-Ye-Kitaev model, derive operator growth based on SU(2) and Heisenberg-Weyl symmetries, and generalize the discussion to conformal field theories. Finally, we use techniques from quantum optics to study operator evolution with quantum information tools such as entanglement and Renyi entropies, negativity, fidelity, relative entropy, and capacity of entanglement.http://doi.org/10.1103/PhysRevResearch.4.013041 |
| spellingShingle | Pawel Caputa Javier M. Magan Dimitrios Patramanis Geometry of Krylov complexity Physical Review Research |
| title | Geometry of Krylov complexity |
| title_full | Geometry of Krylov complexity |
| title_fullStr | Geometry of Krylov complexity |
| title_full_unstemmed | Geometry of Krylov complexity |
| title_short | Geometry of Krylov complexity |
| title_sort | geometry of krylov complexity |
| url | http://doi.org/10.1103/PhysRevResearch.4.013041 |
| work_keys_str_mv | AT pawelcaputa geometryofkrylovcomplexity AT javiermmagan geometryofkrylovcomplexity AT dimitriospatramanis geometryofkrylovcomplexity |