What are the perspectives of trapped-ion quantum computing in 2026? [closed]

Cold trapped ions are believed to be one of the leading candidate systems for building a quantum computer. The development of trapped-ion quantum computers was rapid and impressive for decades. However, it seems that we are still very far from a practically useful trapped-ion quantum computer.

Recently, the 98-qubit Helios quantum computer was announced by Quantinuum. The reported two-qubit gate fidelity is $99.92 \%$. We can speculate that it is possible to achieve fidelities above $99.99\%$ (like in this paper). This would allow $\sim 40$-depth circuits executed in a 98-qubit register with $\sim 4000$ gates, with a circuit fidelity $\gtrsim 0.5$. While this could be an impressive achievement far beyond the capabilities of classical computers, this is significantly below the requirements for practically useful quantum algorithms/simulations (for example, it is claimed in this paper that we need $10^{7}$ entangling gates for quantum simulation of a $40$-qubit Heisenberg model).

Similar estimates can be made for the IonQ quantum computer.

I have no idea how can the number of gates increased by orders of magnitude with current technologies, particularly, with the approaches of Quantinuum and IonQ, even though they could be the most successful attempts ever made. The possible issues include

• long transport time required for operating large qubit registers,
• stringent fidelity requirements,
• large number of qubits required for implementing quantum error correction, which makes the above issues even more severe,
• exceptional requirements on the stability of laser system and/or control electronics.

So, does trapped-ion quantum computing have a future?