Description
In trapped ion quantum computers, two-qubit gates are mediated by collective vibrations of ions within a single trap, featuring high connectivity between spatially separated qubits. However, conventional mechanisms rely on single-mode excitations which creates a strong trade-off between gate speed and fidelity in larger ion systems. Modern architectures circumvent this using small ion traps that are connected by physically shuttling the ions. However, shuttling introduces significant time and resource overheads, making it the primary bottleneck when scaling trapped-ion processors.
An alternative pathway to increasing quantum logic rates in trapped-ion systems is to employ ‘fast gate’ protocols, where ions are subjected to sequences of spin-dependent kicks (SDKs) driven by broadband laser pulses. Previous studies suggest fast gates enable MHz quantum logic rates without any reduction in gate speed in long ion chains, as well as supporting more flexible trap geometries. However these studies have been limited to nearest-neighbour operations.
We present a theoretical study of fast all-to-all entangling gates in trapped-ion processors. We explore how different regimes of the ion dynamics can be exploited to achieve high-fidelity, non-local entangling operations in scalable trapped-ion crystals. In particular, we identify a regime of phonon-mediated entanglement in which gates between arbitrary ion pairs can be performed in approximately $1.3-2$ centre-of-mass oscillation periods [1]. We further assess the experimental feasibility of the proposed gate schemes, showing that the required SDK resources are independent of both chain length and qubit separation [2]. These results suggest that fast entangling gate protocols can overcome key scaling bottlenecks in trapped-ion platforms, and they outline pathways toward combining fast operations, high connectivity, and modular scalability in future quantum processors.
[1] I. Savill-Brown, et al. Physical Review Letters 136.19 (2026), p. 190802.
[2] I. Savill-Brown, et al. Physical Review A 113.5 (2026), p. 052610.
| I am the presenting author | Yes |
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