Sideband cooling of small ion Coulomb crystals in a Penning trap

Abstract

We have recently demonstrated the laser cooling of a single ${}^{40}$Ca${}^{+}$ ion to the motional ground state in a Penning trap using the resolved-sideband cooling technique on the electric quadrupole transition S${}_{1/2}\leftrightarrow$ D${}_{5/2}$. Here we report on the extension of this technique to small ion Coulomb crystals made of two or three ${}^{40}$Ca${}^{+}$ ions. Efficient cooling of the axial motion is achieved outside the Lamb-Dicke regime on a two-ion string along the magnetic field axis as well as on two- and three-ion planar crystals. Complex sideband cooling sequences are required in order to cool both axial degrees of freedom simultaneously. We measure a mean excitation after cooling of ${\bar{n}}_{\text{COM}}=0.30(4)$ for the centre of mass mode and ${\bar{n}}_{\text{B}}=0.07(3)$ for the breathing mode of the two-ion string with corresponding heating rates of 11(2) s${}^{-1}$ and 1(1) s${}^{-1}$ at a trap frequency of 162 kHz. The ground state occupation of the axial modes is above 75% for the two-ion planar crystal and the associated heating rates 0.8(5) s${}^{-1}$ at a trap frequency of 355 kHz.

arXiv comment14 pages, 8 figures

References in corpus (15)

• Engineered 2D Ising interactions on a trapped-ion quantum simulator with hundreds of spins
• Frequency Comparison of Two High-Accuracy Al+ Optical Clocks
• Demonstration of a small programmable quantum computer with atomic qubits
• Quantum spin dynamics and entanglement generation with hundreds of trapped ions
• Realization of a scalable Shor algorithm
• EIT ground-state cooling of long ion strings
• Penning traps as a versatile tool for precise experiments in fundamental physics
• Measurement-based quantum computation with trapped ions
• BASE - The Baryon Antibaryon Symmetry Experiment
• Ion Coulomb Crystals
• Resolved-sideband laser cooling in a Penning trap
• Laser Cooling of two trapped ions: Sideband cooling beyond the Lamb-Dicke limit
• Rapid crystallization of externally produced ions in a Penning trap
• Theoretical basis for quantum simulation with a planar ionic crystal in a Penning trap using a triangular rotating wall
• Trapped-ion quantum error-correcting protocols using only global operations

Cited by in corpus (16)

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• Penning micro-trap for quantum computing
• Measurement of ultra-low heating rates of a single antiproton in a cryogenic Penning trap
• Controlling the potential landscape and normal modes of ion Coulomb crystals by a standing wave optical potential
• Sideband cooling of the radial modes of motion of a single ion in a Penning trap
• Doppler Cooled Ions in a Compact, Reconfigurable Penning Trap
• Population dynamics in sideband cooling of trapped ions outside the Lamb-Dicke regime
• Efficient motional-mode characterization for high-fidelity trapped-ion quantum computing
• First principle simulation of ultra-cold ion crystals in a Penning trap with Doppler cooling and a rotating wall potential
• Individual-Ion Addressing and Readout in a Penning Trap
• Sideband thermometry of ion crystals
• Stabilization of cat-state manifolds using nonlinear reservoir engineering
• Pulse optimization for high-precision motional-mode characterization in trapped-ion quantum computers
• Scheme for continuous force detection with a single electron at the level of $10^{-27}\mathrm{N}$
• Formation of Two-Ion Crystals by Injection from a Paul-Trap Source into a High-Magnetic-Field Penning Trap