Haoyang Gao, Harvard University

Robust qudit Hamiltonian engineering and dynamical decoupling from graphical constructions

Hamiltonian engineering and dynamical decoupling has been an important tool in quantum sensing, NMR, and quantum many-body physics for decades. Despite extensive research on this topic, this technique is still limited in spin-1/2 systems. In this poster, we propose a new method for doing robust Hamiltonian engineering and dynamical decoupling in general qudit systems, enabling the exploration of novel many-body phenomena that are inaccessible in spin-1/2 case, and the possibility to do better quantum sensing utilizing the larger dipole moment of higher-spin particles. As an example of showing the power of our method, we designed a robust disorder and interaction decoupling sequence for our experimental platform of interacting nitrogen-vacancy (NV) centers (spin-1 particles), and realized experimentally an order of magnitude improvement in coherence time compared with previous sequences.

As an unrelated work, I will also talk about our recent effort of engineering one-axis twisting (OAT) and two-axis-twisting (TAT) dynamics in a solid state (NV) spin ensemble, which is useful in realizing spin squeezing and another closely related (but different) interaction enhanced metrology method that we call “spin amplification”.