Gao, Haoyang - 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”.