AWS dual-rail transmon erasure line

Raveh Neeman

doi:10.5281/zenodo.22674814

AWS Center for Quantum Computing (named Amazon Center for Quantum Computing in the Apr 2026 paper)

AWS dual-rail transmon erasure line

AWS Center for Quantum Computing (named Amazon Center for Quantum Computing in the Apr 2026 paper) · superconducting circuits · DEMONSTRATED (Mar 2024 / Apr 2026) · 2 physical qubits · access: lab-only

architecture: Dual-rail erasure qubits · Open on the map

Register profile — the machine's variant of its architecture

qubit type: dual rail from two resonantly coupled tunable transmons

gate mechanism: ancilla-mediated bosonic gates

connectivity: pairwise

control: room-temperature control; symmetrically coupled readout resonator

control placement: room-temp

readout: single-shot erasure detection in 384 ns; residual logical error 6.0(2)e-4 per check; induced dephasing 8(3)e-5 per check

gate evidence: no published figure

codes: dual_rail

flags: a component, not a machine

Technologies by layer — the machine's cell per layer

1 Qubit carrier	Transmon · primary ▣ Fig. 1a-b (two coupled transmons); §II ✅ each dual-rail qubit is two resonantly coupled tunable transmons (not cavities)
2 Encoding	Dual-rail (erasure) encoding · primary ▣ Fig. 1a-b (single-excitation subspace); Fig. 2c-d (ILRB) ✅ one excitation across two coupled transmons; erasure error 2.54(1)e-2 per check, residual logical error 6.0(2)e-4 per check (Apr 2026)
3 Gate mechanism	Ancilla-mediated bosonic gates (cat CX, dual-rail CZ, beamsplitter) · primary ▤ §V (Continuous Parallel Erasure Detection); App. F ✅ ancilla-mediated gates with continuous parallel erasure detection: median 7.2e-5 error per gate, detection overhead <1e-5 (Apr 2026)
4 Connectivity / transport	Static nearest-neighbour lattice · primary ▣ Fig. 1a-b (coupled transmon pair + shared resonator) ✅ pairwise coupling
5 Control	Room-temperature electronics + per-qubit coax/flex · primary ▤ 🔎 room-temperature control
6 Readout	Mid-circuit erasure check · primary ▣ Fig. 1 (symmetric resonator + Purcell filter), Fig. 2a-b (χ-matching), Fig. 3; §II-IV ✅ symmetrically coupled resonator (χ_DR/χ <1e-2): single-shot erasure check in 384 ns, residual logical error 6.0(2)e-4, dephasing 8(3)e-5 per check
7 Code	Erasure-adapted codes · primary ▤ 🔎 dual-rail erasure conversion only; code targeted, not run; no distance scaling (L1)
8 Decoder	— none — nothing in this layer ▤ 🔎 no decoder; erasure conversion only, no code run
9 Interconnect	— none — nothing in this layer ◌ 🔎 monolithic single module, no interconnect
10 Manufacturing	Superconducting-qubit lithography (Al/AlOx/Al junctions, Nb wiring, 300 mm) · primary ▤ App. A (Device) 🔎 superconducting tunable-transmon chip; no machine-specific fab detail published

Standard records

QND fidelity / survival → 0.999 · best (residual logical error 6.0e-4 per erasure check)

erasure check in 384 ns · Apr 2026 · source

evidence: ✅ 5 / 10