Towards Improved Quantum Simulations and Sensing with Trapped 2D Ion Crystals via Parametric Amplification

Improving coherence is a fundamental challenge in quantum simulation and sensing experiments with trapped ions. Here we discuss, experimentally demonstrate, and estimate the potential impacts of two different protocols that enhance, through motional parametric excitation, the coherent spin-motion coupling of ions obtained with a spin-dependent force. The experiments are performed on 2D crystal arrays of approximately one hundred $^9$Be$^+$ ions confined in a Penning trap. By modulating the trapping potential at close to twice the center-of-mass mode frequency, we squeeze the motional mode and enhance the spin-motion coupling while maintaining spin coherence. With a stroboscopic protocol, we measure $5.4 \pm 0.9$ dB of motional squeezing below the ground-state motion, from which theory predicts a $10$ dB enhancement in the sensitivity for measuring small displacements using a recently demonstrated protocol [Science $\textbf{373}$, 673 (2021)]. With a continuous squeezing protocol, we measure and accurately calibrate the parametric coupling strength. Theory suggests this protocol can be used to improve quantum spin squeezing, limited in our system by off-resonant light scatter. We illustrate numerically the trade-offs between strong parametric amplification and motional dephasing in the form of center-of-mass frequency fluctuations for improving quantum spin squeezing in our set-up.Comment: 11 pages, 6 figure

The Vehicle, Spring 1990

Table of Contents Poetry & Photos SpellsAmy Sparkspage 5 Rooting inAmy Sparkspage 6 Perfect NightDerrick Hoguepage 7 Virginia DareShane Taylorpage 8-9 Farmer\u27s Wife and DogShane Taylorpage 10 PovertyNancy Holschuhpage 11 A Strong ManBrad Johnsonpage 12-13 PhotoAiman Humaidehpage 13 Stupid Camp Song, Cartoon LifeEdward Schellpage 14 Into midnight, aloneDenise Santorpage 15 Love of the mindDenise Santorpage 16 Sweet LoveKaren Savagepage 17 Fantastic YellowKaren Savagepage 18 Tea-time in WisconsinTom Caldwellpage 19 PhotoTania Sanchezpage 20, 21 Any ThursdayTom Caldwellpage 22 WesteringTom Caldwellpage 23 Watch PocketAnthony Smithpage 24 Voluntary ResolveMatt Mansfieldpage 25-26 Essays A Return from FaithPeter J. Scalespage 27-28 Fiction Eye SieveTara L. Affolterpage 29-31 Persephone and the Worm Rancherpage 32-37 Authors Biographiespage 38-39https://thekeep.eiu.edu/vehicle/1055/thumbnail.jp