University of Innsbruck trapped-ion demonstrator (Institut für Experimentalphysik)
University of Innsbruck trapped-ion demonstrator (Institut für Experimentalphysik)
Register profile — the machine's variant of its architecture
qubit type: optical qubit (40Ca+ S1/2–D5/2, 729 nm)
gate mechanism: laser Molmer-Sorensen
connectivity: chain bus (segmented traps for the QCCD variants)
control: free-space addressed laser control
control placement: room-temp + free-space optics
readout: fluorescence
gate evidence: no published figure
codes: css_4_1_2, holographic, quantum_repetition, stab_10_1_2, stab_5_1_3, stab_8_3_2, steane
Technologies by layer — the machine's cell per layer
| 1 Qubit carrier | Trapped atomic ion · primary ▣ Fig. 1c (3D model of ion-trap processor); Methods ✅ 16–24 ⁴⁰Ca⁺ ions in a linear chain |
| 2 Encoding | Optical narrow-line qubit (ion S–D, atom clock) · primary ▤ §VI.A Trapping and cooling; §VI.B Qubit manipulation ✅ 40Ca+ optical qubit in Zeeman sublevels of 4S1/2 and 3D5/2, manipulated by individually addressed 729 nm pulses |
| 3 Gate mechanism | Mølmer–Sørensen / light-shift laser gate · primary ▣ Fig. 1c (entangling beams); Methods (MS interaction) ✅ laser Mølmer–Sørensen entangling gates on the ⁴⁰Ca⁺ chain |
| 4 Connectivity / transport | Ion-chain motional bus (all-to-all in chain) · primary ▣ Fig. 1c (any ion pair i,j addressable) ✅ linear-chain motional bus, 16–24 ions |
| 5 Control | Free-space laser addressing of ions (AOM/AOD beams) · primary ▣ Fig. 1c (steerable tightly focused 729-nm beams) ✅ free-space addressed laser control; room-temp + free-space optics |
| 6 Readout | Fluorescence state detection (ions, defects) · primary ▤ §VI.C State readout ✅ state readout by fluorescence on the 4S1/2–4P1/2 transition |
| 7 Code | Colour code (transversal Cliffords) · primary ▣ Fig. 1a (7-qubit color code); Figs. 2-3 (FT prep, logical CNOT) ✅ Steane [[7,1,3]]: fault-tolerant universal 2-qubit gate set with T injection, flag-FT (2021; Nature 605, 675) High-rate concatenated codes with transversal gates · alternate ▤ ✅ [[8,3,2]] measurement-free universal FT: logical H, CNOT, transversal CCZ, teleportation; H_L fidelity 81(3)% at p₂=0.025 (2025) Magic-state factory (cultivation / distillation / code switching) · alternate ▣ Fig. 4 (FT magic state |H>_L); Fig. 5 (T-gate injection) ✅ [[7,1,3]] ↔ [[10,1,2]] code switching for a universal FT set incl. T; two logical qubits entangled (Jan 2025) |
| 8 Decoder | — (Atlas gap: ∅G-coherent) · primary ▤ ✅ measurement-free: syndromes mapped into an auxiliary register, coherent feedback unitary replaces mid-circuit measurement; latency-free by construction |
| 9 Interconnect | |
| 10 Manufacturing | Ion-trap fabrication (surface-electrode chips; machined 3D blade traps) · primary ◌ 🔎 ion-trap fabrication (family-determined) Optical / mechanical assembly (lasers, vacuum, objectives) · alternate ◌ 🔎 room-temperature free-space optics assembly (family-determined) |
evidence: ✅ 10 / 14
Pictures
Every picture carries the story of what it shows and its credit line.
