Multiparameter Optimization for Ground-State Cooling of a Mechanical Mode Using Quantum Dots

Cooling a mechanical mode to its motional ground state opens up avenues for both scientific and technological advancements in the field of quantum metrology and information processing. We propose a multiparameter optimization scheme for ground-state cooling of a mechanical mode using quantum dots. Applying the master-equation approach, we formulate the optimization scheme over a broad range of system parameters including detunings, decay rates, pumping rates, and coupling strengths. We implement the optimization scheme on two major types of semiconductor quantum-dot systems: colloidal and epitaxial quantum dots. These systems span a broad range of mechanical-mode frequencies, coupling rates, and decay rates. Our optimization scheme lowers the steady-state phonon number in all cases by several orders of magnitude and thereby the effective temperature of the mechanical mode by more than an order of magnitude. We also calculate the net cooling rate by estimating the phonon decay rate and show that the optimized system parameters also result in efficient cooling. The proposed optimization scheme can be readily extended to other driven systems coupled to a mechanical mode.