Description
Quantum computers will require quantum error-correcting codes. Bivariate Bicycle (BB) codes, a family of qLDPC codes, provide higher encoding rates than planar alternatives such as the surface code. This comes at the cost of requiring some long-range (beyond nearest-neighbour) qubit connections.
Current simulations of BB codes assume long-range connections are equally as costly as nearest-neighbour connections, not accounting for the penalty paid in qubit transport or lower-fidelity long-range couplers, or they assume best-case component-level fidelities (such as a 99.99% fidelity two-qubit gate in ion traps [2510.17286]) which have not yet been demonstrated in a larger quantum computer (where fidelities might only be 99.5% [2606.06455]). While early studies of error-correcting codes rely on simulations such as these, hardware-specific simulations can be more informative, particularly when considering real-world applications.
We present a blueprint and perform realistic simulations for an ion-trap quantum memory designed to distribute 128 logical Bell pairs, ahead of time, for use in a 128-bit quantum authentication token. Our design utilises the long lifetimes of ion traps and is an extension of Quantinuum’s ion-trap quantum computer, Helios. We simulated our design’s performance using the experimental benchmarks of Helios. This included qubit leakage, for which our simulations showed the best mitigation strategy was leakage repumping [1912.13131], and qubit loss, which we mitigated with ‘beacon qubits’ [2604.19481]. For small codes, such as a found [[60, 4, 8]] BB5 code, our simulations correspond to if it had been run on Helios itself with leakage repumping. For larger codes, such as a found [[378, 16, 18]] code that had an equal logical error rate to the [[360, 12, ≤24]] BB code despite encoding 4 more logical qubits, our simulations correspond to our proposed design that can be used to preserve enough logical Bell pairs for a 128-bit authentication token.
| I am the presenting author | Yes |
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