Abstract
We analyze, from a quantum information theory perspective, the possibility of realizing a SU(4) entangled Kondo regime in semiconductor double quantum dot devices. We focus our analysis on the ground state properties and consider the general experimental situation where the coupling parameters of the two quantum dots differ. We model each quantum dot with an Anderson type Hamiltonian including an interdot Coulomb repulsion and tunnel couplings for each quantum dot to independent fermionic baths. We find that the spin and pseudospin entanglements can be made equal, and the SU(4) symmetry recovered, if the gate voltages are chosen in such a way that the average charge occupancies of the two quantum dots are equal, and the double occupancy on the double quantum dot is suppressed. We present density matrix renormalization group numerical results for the spin and pseudospin entanglement entropies, and analytical results for a simplified model that captures the main physics of the problem.
Highlights
Quantum information theory has proved to be a powerful tool to analyze many-body problems in condensed matter physics, both providing new insights into strongly correlated states and in the development of numerical tools [1,2,3]
We show that it is possible to reduce the size of SU(4) symmetry breaking in the entanglement by reducing the double quantum dot (DQD) average occupancy to less that one electron, suppressing charge fluctuations to the doubly occupied states
The ground state is in a charge sector with a total of 4 electrons in the system of which 2 electrons of opposite spin projection are on each quantum dots (QDs)-bath site combination
Summary
Quantum information theory has proved to be a powerful tool to analyze many-body problems in condensed matter physics, both providing new insights into strongly correlated states and in the development of numerical tools [1,2,3]. The development of Dynamical Mean Field Theory as a tool to study the physics of strongly correlated electron systems in the lattice spurred further interest on the Kondo problem and other related multiorbital quantum impurity problems [16] These and other related models present a rich variety of phenomena as singular and non-Fermi liquid behavior and a high sensitivity to external fields and may provide a road for the understanding of strongly correlated materials. [29] showed using a renormalized perturbation theory treatment of the Anderson model, that the low energy effective Hamiltonian is not SU(4)-symmetric unless the original model is SU(4)-symmetric or the local interactions on the DQD are very large [29, 30] These conditions are not met in the experiments of Ref.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
