TING'S QUANTUM ENGINEERS
Optimizing ion traps
through simulation.
A comprehensive study simulating and optimizing 3D RF Paul Traps and Surface Ion RF Traps. We analyzed electrode geometry, RF/DC voltages, trap depth, and ion stability to design optimal configurations for quantum computing applications.
What Is an Ion Trap?
An educational introduction to the physics behind ion confinement
The Task
Understanding and optimizing key performance metrics for ion trap configurations
Our objective is to design, simulate, and optimize a 3D RF Paul trap and a Surface Ion trap in COMSOL by experimenting with electrode geometry and voltages to understand and improve the electrostatic and pseudopotential landscapes that confine a chain of Yb⁺ ions.
Traditional 3D RF Paul Trap
Four RF rod electrodes with two DC endcaps, operating in vacuum for Yb⁺ ion trapping
4 RF rod electrodes
2 DC endcaps
Operates in vacuum
Designed for Yb⁺ ion trapping
True 3D quadrupole field
Rod radius: 1.000 mm
Rod length: 40.000 mm
Rod spacing: 8.873 mm
RF voltage: 75.000 V
DC voltage: 102.900 V
Endcap radius: 7.200 mm
Endcap thickness: 0.845 mm
Endcap distance from trap center: 0.360 mm
Endcap voltage: 2.500 V
RF drive frequency: 6.400 MHz
COMSOL Multiphysics 6.3.0 — Global Evaluation Metrics
Model: 3d_pole_trap(optimized).mph |Date: Nov 23 2025, 00:05
3D Pole Trap Model
Pole Trap Cross Section
Pseudopotential Animation
Surface Ion RF Trap
Microfabricated planar electrode layout with ions floating above the chip surface
Microfabricated planar electrode layout where ions float above the chip surface. More compact but presents unique challenges with shallower trap depths.
Planar electrode geometry
Compact chip-scale design
Scalable for quantum computing
Width of center DC electrode: 0.1143 mm
Width of RF electrodes: 0.1929 mm
Spacing of RF electrodes from center: 0.1929 mm
RF voltage: 328.5714 V
DC voltage: 97.1429 V
Endcap radius: 3.0000 mm
Endcap thickness: 0.2000 mm
Endcap distance from trap center: 0.5000 mm
Endcap voltage: 0.1000 V
RF drive frequency: 30.0000 MHz
Total trap length: 1.2143 mm
Lower trap depth compared to the Paul trap
Sensitive to stray electric fields
Complex electrode shape constraints
Shaping a field direction to create a low pseudopotential zone for the ions
Electrode Geometry
Width/spacing parameter sweeps for optimal field configuration
RF/DC Ratio Tuning
Balancing confinement strength with stability regions
Pseudopotential Curvature
Improving trap depth through field shape optimization
Micromotion Minimization
Offset tuning to reduce excess ion motion
COMSOL Multiphysics 6.3.0 — Global Evaluation Metrics
Model: Surface_trap(v4)1.mph |Date: Nov 23 2025, 02:02
3D Surface Trapped Ion Model
Surface Trap Cross Section
Pseudopotential Animation
Comparison
A detailed comparison of 3D RF Paul Traps vs. Surface Ion Traps
Through COMSOL Multiphysics optimization, we achieved remarkable improvements:
- 3D Trap: 62.9× increase in trap depth (0.184 eV → 11.568 eV)
- Surface Trap: 20.2× increase in trap depth (1.205 eV → 24.359 eV)
- Improved field symmetry and reduced offset distances for better ion positioning
Our optimized designs reveal surprising results:
- Surface traps now achieve 2.1× higher trap depth than 3D traps
- Surface traps consume 32,700× less power while maintaining superior performance
- Both designs demonstrate excellent scalability potential for quantum computing
Conclusion
Through advanced simulation and geometric modelling using COMSOL and optimization, Ting's Quantum Engineers developed two validated simulations for ion confinement systems.
Our work enhances the design pipeline for future quantum technologies and experimental physics, providing a robust foundation for next-generation quantum hardware development.
Academic papers and resources used in this study