Entanglement based observables for quantum impurities

Abstract

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 non-perturbative effects is particularly challenging due to the infinite size of the environment, and the inability of local correlators to capture the build-up 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 characterise the metal-to-insulator phase transition in the system and identify how the (conducting) dot-lead Kondo singlet is quenched by an (insulating) intra-impurity 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.

6 pages, 4 figures, comments are welcome

References in corpus (13)

• Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms
• The density-matrix renormalization group in the age of matrix product states
• Continuous-time Monte Carlo methods for quantum impurity models
• The numerical renormalization group method for quantum impurity systems
• Zero-field Kondo splitting and quantum-critical transition in double quantum dots
• Transport properties and Kondo correlations in nanostructures: the time-dependent DMRG method applied to quantum dots coupled to Wilson chains
• Realizing a Deterministic Source of Multipartite-Entangled Photonic Qubits
• Matrix product state comparison of the numerical renormalization group and the variational formulation of the density matrix renormalization group
• Symmetric inseparability and number entanglement in charge conserving mixed states
• Macroscopic Quantum Entanglement of a Kondo Cloud at Finite Temperature
• Impurity entanglement entropy in Kondo systems from conformal field theory
• Universal Thermal Entanglement of Multichannel Kondo Effects
• Complete state tomography of a quantum dot confined spin qubit

Cited by in corpus (9)

• Anomalous Skin Effects in Disordered Systems with a Single non-Hermitian Impurity
• Quasilocal entanglement across the Mott-Hubbard transition
• Quantifying measurement-induced quantum-to-classical crossover using an open-system entanglement measure
• Efficient separation of quantum from classical correlations for mixed states with a fixed charge
• Next-generation EDIpack: A Lanczos-based package for quantum impurity models featuring general broken-symmetry phases, flexible bath topologies and multi-platform interoperability
• Coherent exchange-coupled nonlocal Kondo impurities
• Quantum entanglement in a pure state of strongly correlated quantum impurity systems
• Ballistic Entanglement Cloud after a Boundary Quench
• Unraveling screening mechanisms in Kondo impurities using an NRG-MPS-based method