In moderately strong magnetic fields, the difference in Land\'e $g$ factors in each of the dots of a two-electron double quantum dot (DQD) may induce oscillations between singlet and triplet states of an entangled pair and lead to a nonequilibrium electron spin polarization in the system. The calculated bipolar polarization reflects the strong spin correlation in the spatially separated pair of electrons that occupy almost degenerate states in a coupled DQD. We will show that this polarization may partially survive the rapid inhomogeneous decoherence caused by random nuclear magnetic fields.In moderately strong magnetic fields, the difference in Land\'e $g$ factors in each of the dots of a two-electron double quantum dot (DQD) may induce oscillations between singlet and triplet states of an entangled pair and lead to a nonequilibrium electron spin polarization in the system. The calculated bipolar polarization reflects the strong spin correlation in the spatially separated pair of electrons that occupy almost degenerate states in a coupled DQD. We will show that this polarization may partially survive the rapid inhomogeneous decoherence caused by random nuclear magnetic fields.

arXiv:cond-mat/0508566Physical Review BJul 20, 20063 citations

Double quantum dot turnstile as an electron spin entangler

Xuedong Hu, S. Das Sarma

We study the conditions for a double quantum dot system to work as a reliable electron spin entangler and the efficiency of a beam splitter as a detector for the resulting entangled electron pairs. In particular, we focus on the relative strengths of the tunneling matrix elements, the applied bias and gate voltage, the necessity of time-dependent input/output barriers, and the consequence of considering wave packet states for the electrons as they leave the double dot to enter the beam splitter. We show that a double quantum dot turnstile is, in principle, an efficient electron spin entangler or entanglement filter because of the exchange coupling between the dots and the tunable input/output potential barriers, provided certain conditions are satisfied in the experimental setup.We study the conditions for a double quantum dot system to work as a reliable electron spin entangler and the efficiency of a beam splitter as a detector for the resulting entangled electron pairs. In particular, we focus on the relative strengths of the tunneling matrix elements, the applied bias and gate voltage, the necessity of time-dependent input/output barriers, and the consequence of considering wave packet states for the electrons as they leave the double dot to enter the beam splitter. We show that a double quantum dot turnstile is, in principle, an efficient electron spin entangler or entanglement filter because of the exchange coupling between the dots and the tunable input/output potential barriers, provided certain conditions are satisfied in the experimental setup.

arXiv:cond-mat/0307024Physical Review BMar 12, 200431 citations

Double Quantum Dot as a Filter for Spin Entanglement

Xuedong Hu, S. Das Sarma

APSMar 1, 20040 citations

Entanglement of two interacting electrons in a driven double quantum dot structure

John Boviatsis, Evangelos Voutsinas, Antonios Fountoulakis

Superlattices and MicrostructuresApr 25, 200712 citations

In moderately strong magnetic fields, the difference in Land\'e

g

factors in each of the dots of a two-electron double quantum dot (DQD) may induce oscillations between singlet and triplet states of an entangled pair and lead to a nonequilibrium electron spin polarization in the system. The calculated bipolar polarization reflects the strong spin correlation in the spatially separated pair of electrons that occupy almost degenerate states in a coupled DQD. We will show that this polarization may partially survive the rapid inhomogeneous decoherence caused by random nuclear magnetic fields.