@article{12132,
  author = {Athreya Shankar and Chen Tang and Matthew Affolter and Kevin Gilmore and Daniel Dubin and Scott Parker and Murray Holland and John Bollinger},
  title = {Broadening of the drumhead mode spectrum due to in-plane thermal fluctuations of two-dimensional trapped ion crystals in a Penning trap},
  abstract = {Two-dimensional crystals of ions stored in Penning traps are a leading platform for quantum simulation and sensing experiments. For small amplitudes, the out-of-plane motion of such crystals can be described by a discrete set of normal modes called the drumhead modes, which can be used to implement a range of quantum information protocols. However, experimental observations of crystals with Doppler-cooled and even near-ground-state-cooled drumhead modes reveal an unresolved drumhead mode spectrum. In this work, we establish in-plane thermal fluctuations in ion positions as a major contributor to the broadening of the drumhead mode spectrum. In the process, we demonstrate how the confining magnetic field leads to unconventional in-plane normal modes, whose average potential and kinetic energies are not equal. This property, in turn, has implications for the sampling procedure required to choose the in-plane initial conditions for molecular dynamics simulations. For current operating conditions of the NIST Penning trap, our study suggests that the two dimensional crystals produced in this trap undergo in-plane potential energy fluctuations of the order of 10 mK. Our study therefore motivates the need for designing improved techniques to cool the in-plane degrees of freedom.},
  year = {2020},
  journal = {Physical Review A},
  volume = {102},
  chapter = {053106},
  pages = {053106},
  month = {2020-11},
  url = {https://journals.aps.org/pra/abstract/10.1103/PhysRevA.102.053106},
  doi = {10.1103/PhysRevA.102.053106},
}