Squeezed light mode (CV) squeezed

An optical mode whose vacuum fluctuations are redistributed between conjugate quadratures by a parametric process — down-conversion in a χ⁽²⁾ medium or four-wave mixing in a χ⁽³⁾ one (SiN): one quadrature drops below vacuum noise, the other rises. Predicted in the 1970s, first observed in 1985; the lineage that matters is waveguide squeezers feeding CV cluster states and GKP encoding. Attributes: flying carrier, heralded generation at ~1 µs; readout by single-photon detection at ~10 ns, destructive, not mid-circuit; electro-optic room-temperature control, Gaussian-plus-loss errors, photonic-IC fabrication.

Squeezing is a loss thermometer: the medium can produce arbitrarily strong quadrature reduction, but every dB of loss between generation and detection pulls the measured value toward vacuum, so the number describes the optical path, not the squeezer. Hence 15 dB in bulk optics D[344] against 1.4 dB measured on chip, over 10 dB once a 4 dB homodyne loss budget is subtracted D[345]. Do not conflate raw quadrature squeezing with the effective squeezing of a GKP grid state, which folds in non-Gaussian preparation fidelity as well as loss: fault tolerance prices the latter at ~9.75 dB against 0.62 dB on chip D[174]. Only lower loss, better coupling and higher detection efficiency move it.

The molecular vibronic-spectrum application of Gaussian boson sampling with squeezed light is a linear statistic of the output; the characteristic function of displaced squeezed vacuum is computable exactly in polynomial time, so the spectrum is classically estimable to the experiment's additive accuracy P[889].

The on-chip-to-bulk gap is ~13 dB, the GKP gap ~9 dB.

Shi et al.'s 1.4 dB, measured on PPLN TFLN [345], is an independent on-chip squeezing figure; the 0.62 dB GKP effective squeezing rests on Xanadu alone. The >10 dB TFLN figure is loss-corrected, not measured, and stated at one pump power, so it is not comparable with the 15 dB bulk-optics measurement. The ~9.75 dB fault-tolerance requirement, rounded to ~10 dB in the main report, has no single primary source. Xanadu's CAD 195 M and USD 686 M both come from its 2026-08-31 release, not an audited filing.

Squeezers ride the CV photonic-IC line — SiN and thin-film lithium niobate with periodic poling. Merchant TFLN supply is thin: HyperLight (USD 37 M Series B, 2024-09) and Lightium (USD 7 M seed) Pfact, plus the PIXEurope pilot line fact. Xanadu builds rather than buys; no cost per squeezer is public. Poling uniformity and waveguide loss are the yield-limiting defects, both acting on the headline dB. I/O is one pump and one homodyne chain per mode plus phase locking; Aurora ran 35 chips at 12 modes on a 1 MHz cycle D[173]. At 10³ modes the wall is pump distribution and phase stability; at 10⁴–10⁶, detector and DAC channel count. No ECCN names squeezers; 4A906 catches the machine fact.

Architectures: the continuous-variable photonic GKP architecture and the boson sampler, primary carrier in both. The register lists 7 machines using it, among them Aurora, Borealis and the Jiuzhang line up to 4.0. Requires a photonic-IC foundry; provides the modes for CV Gaussian gates with GKP-assisted non-Gaussian operations and for GKP grid encoding on Xanadu's architecture. It replaces discrete photons as carrier — DV trades erasure-dominated errors for Gaussian-plus-loss ones, and switching costs the whole detector chain. Squeezing level sets the error floor of every CV operation, bounding the derived clock indirectly rather than contributing a gate time. Verification: 0.62 dB is single-source and unreplicated; the independent TFLN result measures raw squeezing, and its ">10 dB" is inferred by subtracting detection loss D[345].

Money.
2025-11-06 · Xanadu · DARPA QBI Stage B · up to USD 15 M · announced fact
2026-03-26 · Xanadu · SPAC with Crane Harbor · ~USD 302 M gross, ~40% below plan · closed Cfact
2026-08-28 · Xanadu · Canadian factory funding · CAD 195 M · confirmed fact

Market & supply chain. No merchant squeezer exists; upstream the tradable goods are TFLN wafers and poling from two small vendors — concentration risk for anyone not vertically integrated. Only G3/G4 pay for squeezing quality.

IP & standards. No dated patent family specific to on-chip squeezers as of 4 Sep 2026, and no standard defines how effective squeezing is reported.

Roadmaps & track record. (2026-08-31 · loss 24.1× → 1.0× by 2030 · not due); (2026-08-31 · 200 logical qubits by 2029 · not due). Good disclosure record, but every squeezing promise is forward-dated.

Strategic reading. Squeezing quality, not mode count, gates the CV bet: if the on-chip GKP figure does not move, the 2030 target fails and CV loses to DV fusion, having no alternative carrier. If it moves, TFLN and poling suppliers become strategic.

Confirm by 2028: on-chip GKP effective squeezing above 2 dB with its loss budget; demote if still below 1 dB. Best case 2029: a second group publishes a competing GKP figure. Worst case: integration loss pins it near 1 dB and CV/GKP stays a research architecture. Open: does loss fall as the roadmap claims; can poled TFLN reach GKP-grade fidelity.