We develop a theoretical model to describe the dissipative dynamics ofsinglet-triplet (S-T_0) qubits in GaAs quantum dots. Using the concurrenceexperimentally obtained as a guide, we show that each logical qubit is coupledto its own environment because the decoherence effect can be described byindependent dephasing channels. Given the correct description of theenvironment, we study the dynamics of concurrence as a function of thetemperature, the constant coupling between the system and the environment, thepreparation time, and the exchange coupling. Although the reduction of theenvironment coupling constant modifies the entanglement dynamics, wedemonstrate that temperature emerges as a crucial variable and a variation ofmillikelvins significantly modifies the generation of entangled states.Furthermore, we show that the exchange coupling together with the preparationtime strongly affects the entanglement dissipative dynamics.
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