Thermal Entanglement and Correlated Coherence in Two Coupled Double Quantum Dots Systems

Abstract

In this work, we investigate the thermal quantum correlations in two coupled double semiconductor charge qubits. This is carried out by deriving analytical expressions for both the thermal concurrence and the correlated coherence. We study, in detail, the effects of the tunneling parameters, the Coulomb interaction and the temperature on the thermal entanglement and on the correlated coherence. It is found that the Coulomb potential plays an important role in the thermal entanglement and in the correlated coherence of the system. The results also indicate that the Coulomb potential can be used for significant enhancement of the thermal entanglement and quantum coherence. One interesting aspect is that the correlated coherence capture all the thermal entanglement at low temperatures, i.e, the local coherences are totally transferred to the thermal entanglement. Finally, we focus on the role played by thermal entanglement and the correlated coherence responsible for quantum correlations. We show that in all cases, the correlated coherence is more robust than the thermal entanglement so that quantum algorithms based only on correlated coherence may be more robust than those based on entanglement. Our results also show that the entanglement can be tuned by varying the Coulomb interaction between electrons.

Pairwise quantum correlations in four-level quantum dot systems

“…Quantum dot systems usually are treated in quantum information as qubit systems whenever the study of entanglement concerns the mixed state case [39][40][41]. Notably, description of quantum dots in terms of the Hubbard model as qubits is valid only in some specific cases requiring more restrictive constraints.…”

Thermal entanglement and quantum coherence of a single electron in a double quantum dot with Rashba Interaction

“…Moreover, in [28,29], the quantum dynamics and the entanglement of two electrons inside the coupled double quantum dots were addressed, while in [30][31][32][33] aspects related to the quantum correlations and the decoherence were investigated. Furthermore, several other properties have been investigated: quantum teleportation based on the double quantum dots [34], the quantum noise due to phonons induce steady-state in a double quantum dot charge qubit [35], multielectron quantum dots [36] and thermal quantum correlations in two coupled double semiconductor charge qubits [37] were also reported. More recently, a conceptual design of quantum heat machines has been developed using two coupled double quantum-dot systems as a working substance [38].…”

Intrinsic decoherence effects on correlated coherence and quantum discord in XXZ Heisenberg model

“…However, it is a strenuous measure to calculate, and analytical expressions of QD were only obtained for two-qubit states [26,27] and quantum X-states ( see for instance the works [28][29][30][31] and references therein). Quantum correlations have been studied in many quantum systems, such as Heisenberg spin chain models (for instance, spin-1 Heisenberg chains [32], anisotropic spin-1/2 XY chain in transverse magnetic field [33]) and quantum dot systems such as two coupled double quantum dots systems [34,35] and double quantum dot system with single electron under Rashba interaction [36] ). Recently, considerable attention has been dedicated to studying the influence of the Dzyaloshinsky-Moriya (DM) interaction and the KSEA (Kaplan, Shekhtman, Entin-Wohlman, and Aharony) interaction on the quantum features of specific quantum systems [37][38][39][40].…”