Canonical Hamiltonian ensemble representation for the free induction decay of NV centers

Mu Che LIN^1*, Ping-Yuan Lo², Hong-Bin Chen¹

¹Department of Engineering Science, National Cheng Kung University, Tainan, Taiwan
²Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan

* Presenter:Mu Che LIN, email:grace032630@gmail.com

In contrast to the conventional open quantum system theory, which typically studies the dynamics of reduced system along time axis, the recently proposed theory of canonical Hamiltonian ensemble representation (CHER) transforms the time evolution into frequency domain representation, capable of characterizing the non-classicality of dynamical process. In this work, we investigate the CHER for the free induction decay of nitrogen-vacancy (NV) center in diamond. We found that the CHER is sensitive not only to the external magnetic field, but also to the polarization of the ambient nuclear-spin bath, particularly the orientation of the polarization. Transverse component of the nuclear-spin polarization will induce negative values in CHER, and increasing magnetic field will further enhance the negativity, which reveals the nonclassical nature of the NV FID process.

Keywords: Open quantum system, Canonical Hamiltonian ensemble representation, dephasing dynamics, NV-center