Stocker, Lidia; Sack, StefanISTA; Ferguson, Michael S.; Zilberberg, Oded
Quantum impurities exhibit fascinating many-body phenomena when the small interacting impurity changes the physics of a large noninteracting environment. The characterisation of such strongly correlated nonperturbative effects is particularly challenging due to the infinite size of the environment, and the inability of local correlators to capture the buildup of long-ranged entanglement in the system. Here, we harness an entanglement-based observable—the purity of the impurity—as a witness for the formation of strong correlations. We showcase the utility of our scheme by exactly solving the open Kondo box model in the small box limit, and thus describe all-electronic dot-cavity devices. Specifically, we conclusively characterize the metal-to-insulator phase transition in the system and identify how the (conducting) dot-lead Kondo singlet is quenched by an (insulating) intraimpurity singlet formation. Furthermore, we propose an experimentally feasible tomography protocol for the measurement of the purity, which motivates the observation of impurity physics through their entanglement build up.
Physical Review Research
We thank G. Blatter, T. Ihn, K. Ensslin, M. Goldstein, C. Carisch, and J. del Pino for illuminating discussions and acknowledge financial support from the Swiss National Science Foundation (SNSF) through Project No. 190078, and from the Deutsche Forschungsgemeinschaft (DFG) - Project No. 449653034. Our numerical implementations are based on the ITensors JULIA library .
Stocker L, Sack S, Ferguson MS, Zilberberg O. Entanglement-based observables for quantum impurities. Physical Review Research. 2022;4(4). doi:10.1103/PhysRevResearch.4.043177
Stocker, L., Sack, S., Ferguson, M. S., & Zilberberg, O. (2022). Entanglement-based observables for quantum impurities. Physical Review Research. American Physical Society. https://doi.org/10.1103/PhysRevResearch.4.043177
Stocker, Lidia, Stefan Sack, Michael S. Ferguson, and Oded Zilberberg. “Entanglement-Based Observables for Quantum Impurities.” Physical Review Research. American Physical Society, 2022. https://doi.org/10.1103/PhysRevResearch.4.043177.
L. Stocker, S. Sack, M. S. Ferguson, and O. Zilberberg, “Entanglement-based observables for quantum impurities,” Physical Review Research, vol. 4, no. 4. American Physical Society, 2022.
Stocker L, Sack S, Ferguson MS, Zilberberg O. 2022. Entanglement-based observables for quantum impurities. Physical Review Research. 4(4), 043177.
Stocker, Lidia, et al. “Entanglement-Based Observables for Quantum Impurities.” Physical Review Research, vol. 4, no. 4, 043177, American Physical Society, 2022, doi:10.1103/PhysRevResearch.4.043177.
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