Speaker: Emely Wiegand(Department of Microtechnology and Nanoscience, Chalmers University of Technology, Gothenburg, Sweden)

Place: Physics Building 208 

Date and Time: 4:15pm on May 1

Title:  Ultimate quantum limit for amplification: a single atom in front of a mirror 

Abstract: 

We propose a method to amplify a reflected signal by driving an artificial atom in a semi-infinite transmission line (atom in front of a mirror). The artificial atom can be described by a three-level system. We drive the transition between the ground state |1> and second excited state |3>. The small decay rate of the first excited state compared to the decay rate of the second excited state, $\Gamma_{21}/\Gamma_{32} << 1$ leads to a population inversion and enables amplification. By probing the |2>-|1> transition of the atom, we can achieve a maximum amplification of 25 %, which is twice what we would obtain without the mirror.

Host: Prof. IoChun Hoi