Researchers obtain tunable coherent inhabitants trapping in a double quantum dot system

A analysis group has achieved coherent inhabitants trapping (CPT) in a semiconductor double quantum dot (DQD) system.

CPT is a vital phenomenon of quantum interference, which was first noticed in a three-level atom in an optical experiment. In such a three-level system, two states are coupled to a 3rd intermediate state. When the frequency and part of the driving subject are correctly tuned, the primary two states type a superposition state that decouples from the intermediate state. This superposition state is named the “darkish state” because it doesn’t reply to the probe subject, giving rise to intriguing phenomena akin to electromagnetically induced transparency.

The darkish state has essential purposes in quantum info processing, however hasn’t been nicely applied in DQD programs. Not like the standard three-level atomic system, the inner construction and dynamics of DQD can notice intrinsic CPT with out an exterior driving subject, making it a promising platform for quantum computing.

To implement CPT within the DQD system, the group leveraged the intrinsic properties of the vitality ranges in Ge and Si programs. With none driving subject, they measured the leakage present by way of the DQD within the Pauli Spin Blockade (PSB) and noticed a major dip within the present at zero bias, indicating the formation of darkish states and the incidence of CPT. Moreover, the group demonstrated the flexibility to selectively create a darkish state and the associated CPT course of by making use of a longitudinal drive to the DQD system.

The group additionally delved deeply into the odd-even impact induced by a longitudinal driving subject. Researchers noticed that when the driving frequency meets sure circumstances, the present reveals enhancement or suppression similar to odd and even orders of harmonics.

This phenomenon gives a contemporary perspective for understanding and using CPT. Moreover, the group discovered that the sign depth and width of CPT might be successfully modulated by adjusting the longitudinal driving subject.

The conclusion of CPT within the DQD system exhibits that the semiconductor quantum dot system will not be solely a great platform for understanding quantum interference but additionally a robust device for high-precision quantum info processing. This work clearly demonstrates the potential tunability of the longitudinally pushed DQD system, paving the way in which for sensible utility of semiconductor quantum dot programs in quantum computing.

The findings are printed within the journal Nano Letters.

The group was led by Guo Guangcan, Prof. Guo Guoping and Prof. Li Haiou from the College of Science and Expertise of China (USTC), collaborating with Researcher Zhang Jianjun from the Institute of Physics of the Chinese language Academy of Sciences (CAS).