The paper explores the use of coupled semiconductor quantum dots as quantum gates, focusing on the exchange coupling between electron spins. The authors determine the exchange coupling $J$ as a function of magnetic and electric fields, and the inter-dot distance, using the Heitler-London and Hund-Mulliken approaches. They find that $J$ changes sign at a finite magnetic field, leading to a significant jump in magnetization, and then decays exponentially. The study also discusses the effects of dephasing due to nuclear spins in GaAs, showing that it can be strongly suppressed by dynamical nuclear spin polarization or magnetic fields. The paper concludes with experimental implications, suggesting methods to measure the exchange coupling and spin responses, and discusses the potential for using coupled quantum dots in quantum computing networks.The paper explores the use of coupled semiconductor quantum dots as quantum gates, focusing on the exchange coupling between electron spins. The authors determine the exchange coupling $J$ as a function of magnetic and electric fields, and the inter-dot distance, using the Heitler-London and Hund-Mulliken approaches. They find that $J$ changes sign at a finite magnetic field, leading to a significant jump in magnetization, and then decays exponentially. The study also discusses the effects of dephasing due to nuclear spins in GaAs, showing that it can be strongly suppressed by dynamical nuclear spin polarization or magnetic fields. The paper concludes with experimental implications, suggesting methods to measure the exchange coupling and spin responses, and discusses the potential for using coupled quantum dots in quantum computing networks.