Jiuzhang 4.0
Jiuzhang 4.0
Register profile — the machine's variant of its architecture
qubit type: squeezed light (Gaussian boson sampling); no qubit encoding
gate mechanism: programmable Gaussian interferometer - three cascaded fully-connected 16-mode interferometers joined by two delay-loop arrays; 4.0 is programmable where 1.0 was a fixed circuit; no homodyne feed-forward and no adaptivity
connectivity: cubic connectivity scaling (16^3 = 4,096) through 16 physical detection channels addressing 8,176 effective modes
control: electro-optic control
control placement: room-temp electro-optic
readout: SNSPD (pseudo-PNR), destructive; overall system efficiency 51%, squeezed-state generation efficiency 92%
gate evidence: no published figure
flags: estimated baseline
Technologies by layer — the machine's cell per layer
| 1 Qubit carrier | Squeezed light mode (CV) · primary ▣ Fig. 1 (experimental setup); Extended Data Fig. 2 (single-/cross-OPO indistinguishability) ✅ 1,024 input squeezed states (Gaussian boson sampling); squeezed-state generation efficiency 92%; no qubit encoding (May 2026) |
| 2 Encoding | — none — nothing in this layer ▣ Fig. 1 (principle of the spatial-temporal hybrid encoding circuit) ✅ no encoding — GBS samples raw Gaussian states over 8,176 hybrid spatial–temporal modes |
| 3 Gate mechanism | Programmable linear-optical interferometer (no entangling primitive) · primary ▤ main text (photonic circuit; source filtering, Fig. S5) ✅ programmable circuit: three cascaded fully-connected 16-mode interferometers inter-connected by 2 delay-loop arrays; no entangling primitive (the 99.8% / >40 dB MZIs are the squeezed-light spectral filters) CV Gaussian gates + GKP-assisted non-Gaussian operations · alternate ▣ Extended Data Fig. 3 (cascaded interferometers interconnected by delay loops) ✅ partial g_cv: programmable Gaussian interferometer with no homodyne feed-forward and no adaptivity |
| 4 Connectivity / transport | Photonic switching / routing (electro-optic, feed-forward) · primary ▣ Fig. 1 (spatial-temporal hybrid encoding, 16^3 = 4,096 connectivity); Extended Data Fig. 3 (delay loops) ✅ spatial–temporal hybrid multiplexing: cubic scaling 16³ = 4,096 via 16 physical detection channels addressing 8,176 effective modes |
| 5 Control | Electro-optic drive + feed-forward electronics (room temperature) · primary ▣ Extended Data Fig. 4 (schematic of the phase locking system); Extended Data Fig. 1 (PZT-stabilised MZI) ✅ electro-optic control; 25.6 µs per sample |
| 6 Readout | Single-photon detection (SNSPD / TES) · primary ▣ Fig. 1 (experimental setup, 16 detection channels) ✅ SNSPD (pseudo-PNR), destructive; overall system efficiency 51%; 3,050 photons in largest detection event |
| 7 Code | |
| 8 Decoder | |
| 9 Interconnect | |
| 10 Manufacturing | Bulk-optics and fibre assembly (photonic samplers) · primary ▣ Extended Data Fig. 1 (free-space unbalanced MZI, PZT-mounted mirror); Extended Data Fig. 3 ✅ bulk-optics / fibre-assembly photonic apparatus |
Standard records
code rate k/n → 3.9e+4 Hz · best (1 / 25.6 us sampling rate)
May 2026 · source
device yield → 0.51 · typical (overall system efficiency)
May 2026 · source
evidence: ✅ 8 / 11