Speaker: Zeng-Zhao Li
 Beijing Computational Science Research Center    

Abstract: In this talk, I present two of our recent proposals: (1)Cooling a nanomechanical resonator (NAMR) by a triple quantum dot (TQD); (2)Probing the quantum behavior of an NAMR coupled to a double quantum dot (DQD). For the former one, by tuning the degeneracy of the two lowerenergy states in the TQD, an electron can be trapped in a dark state caused by destructive quantum interference between the two tunneling pathways to the higher-energy state. Therefore, ground-state cooling of an NAMR can be achieved when electrons absorb readily and repeatedly energy quanta from the NAMR or excitations. For the latter, the NAMR is coupled to a double quantum dot (DQD), which acts as a quantum transducer and is further coupled to a quantum-point contact (QPC). By measuring the current correlation spectrum of the QPC, shifts in the DQD energy levels, which depend on the phonon occupation in the NAMR, are determined. Quantum behaviors of the NAMR could, thus, be observed.

Date&Time: August 31, 2012 (Friday), 14:30 – 15:30
Location: 606 Conference Room