EQuAL Student Seminar: Winston Peloso

Approaches to Entanglement Enhanced Metrology in the Solid State

Near-surface nitrogen vacancy (NV) center spins in diamond are an established platform for nanoscale quantum sensing. One attraction of quantum sensors comes from the potential to use entangled states to achieve more favorable sensitivity scaling than is possible classically; however, the positional disorder inherent to many solid state spin qubit platforms strongly limits the squeezing generated by the native spin-spin interactions. I will discuss two approaches developed in our lab for ameliorating the issue of strong positional disorder. The first is a hybrid approach that leverages the tunable self-assembly of custom DNA fragments, called DNA origami, which provides a nanoscale molecular breadboard for the fabrication of positionally ordered spins. Proximal NV centers which strongly interact with the DNA spin array could then provide control and readout of the squeezing generated in the array. The second approach, instead of fabricating a physical lattice external to the diamond, modifies the interactions within an ensemble of NV centers in a positiondependent way, increasing the uniformity of the interaction strengths and thus the degree of squeezing. This approach leverages pulsed magnetic field gradients in concert with the usual pulsed microwaves. Both seek to deploy techniques from the mature field of NMR in novel platform enabled by recent materials advances. Highlighting recent conceptual progress, I will illustrate the how and why of these approaches to entanglement enhanced metrology in the solid-state.