Betting on light / Not bigger fridges / Whitepaper v5.4

Quantum, in modules.
Linked by light.

QONTOS-1 is a 1,000 qubit superconducting quantum computer, built as two modules and connected with light. The first of five generations on the way to fault tolerance at datacenter scale.

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QONTOS-1 · TWO-MODULE SYSTEM Photonic interconnect HERALDED BELL PAIRS · 1550 nm Module A 500 TRANSMONS T ≤ 20 mK Module B 500 TRANSMONS T ≤ 20 mK 100 mK STAGE η ≥ 0.1% Fraw ≥ 0.85 d = 5 CYCLE 1 μs LINK ≤ 25 μs
Runtime live
Physical qubits
1,000
2Q gate target
5×10⁻³
Transduction
η ≥ 0.1%
First logical
d = 5
Full spec →
The first machine

One thousand qubits. Below twenty millikelvin. Linked by light.

QONTOS-1 is specified to a number. Every target carries its evidence basis: the engineering objective, the measurement protocol, and the gate it must pass.

Compute
Physical qubits1,000
Modules2 · 5 chiplets each
Latticeheavy hex
SubstrateTa on Si
Base temperature≤ 20 mK
T1 coherence≥ 200 µs
Gates
Single qubit gate1×10⁻⁴
Two qubit gate5×10⁻³
Readout fidelity99.0%
Stabilizer cycle1 µs
Photonic link
Wavelength1,550 nm
Transduction η≥ 0.1% base
Bell pair fidelityraw ≥ 0.85
End to end latency≤ 25 µs
Software
Runtime statusoperational
DecoderMWPM, FPGA
Feed forward≤ 10 µs
Proof chainSHA-256, 3 layer
Full specification Whitepaper v5.4
Cryogenic envelope
295 K to ≤ 20 mK
295 K Room temperature Control rack, AWGs, digitisers, FPGA sequencer 50 K First cooling stage Wiring break, attenuators 4 K Second cooling stage JTWPA, isolators, multiplex 100 mK Still, intermediate Photonic transducer microwave to optical ≤ 20 mK Mixing chamber 500 transmon qubit chip Purcell filters, resonators OPTICAL IO PASSIVE BUDGET < 1 µW COOLING POWER ≥ 25 µW @ 20 mK
System architecture

Three domains. One machine.

Compute, interconnect, and control, coordinated by a software runtime that exposes one execution model to the application layer.
Compute

Superconducting modules.

Five chiplets per module. One hundred tantalum on silicon transmons each. Heavy hex lattice with tunable coupler CZ gates. Mixing chamber stage at twenty millikelvin.

T1 ≥ 200 µs
1Q gate · 1×10-4
2Q gate · 5×10-3
Interconnect

Microwave to optical link.

An electro optic resonator up converts microwave photons to 1,550 nanometers. An SNSPD coincidence click heralds a Bell pair between modules. Failed attempts do not corrupt the logical state.

η ≥ 0.1% base, ≥ 0.5% aggressive
F raw ≥ 0.85, purified ≥ 0.98
Latency ≤ 25 µs at 5 m
Control

Real time decoder farm.

Arbitrary waveform generators at one nanosecond sample rate, sub nanosecond trigger jitter, and an FPGA sequencer running an end to end MWPM decoder pipeline within the feed forward budget.

Cycle · 1 µs
Syndrome ingest ≤ 5 µs
Feed forward ≤ 10 µs
The real time loop ties the three domains together.
Nested timescales, ns to ms
1 ns 10 ns 100 ns 1 µs 10 µs 100 µs 1 ms 10 ms COMPUTE Single qubit gate 20 ns COMPUTE Two qubit gate 60 ns COMPUTE Dispersive readout 1 µs CONTROL Stabilizer cycle 1 µs CONTROL Syndrome processing 5 µs CONTROL Feed forward 10 µs INTERCONNECT Bell pair attempt 100 µs
QONTOS-1 validates the real-time loop and the probabilistic photonic link. The decoder ingests syndromes in five microseconds, feed forward completes in ten, and cross-module logical operations remain a rate-limited research objective until purified Bell-pair supply improves.
QONTOS family

Five generations. Four gates. No calendar dates.

From architecture validation at QONTOS-1 to datacenter-scale research studies at QONTOS-5. Each transition is gated on the prior generation's acceptance criteria.
QONTOS-1 Architecture validation2 modules, ~10³ qubits, first logical d = 5 Target
QONTOS-2 Logical qubit advantage4 to 8 modules, 10s of logical qubits, d = 9 to 11 Scenario
QONTOS-3 First useful FTQC pilot16 to 32 modules, 50 to 100 logical qubits, d = 11 to 13 Scenario
QONTOS-4 Research vision64 to 128 modules, 500 to 1,000 logical qubits Research
QONTOS-5 Architecture study500 to 2,000+ modules, 10³ to 10⁴+ logical qubits, d ≥ 21 Research
Physical to logical qubit scale log to log
TARGET SCENARIO RESEARCH 10³ 10⁴ 10⁵ 10⁶ 10⁷ Physical qubits 10⁰ 10¹ 10² 10³ 10⁴ Logical qubits 100:1 1,000:1 QONTOS-1 QONTOS-2 QONTOS-3 QONTOS-4 QONTOS-5
Runs against today

One runtime, four backends.

The QONTOS Python runtime compiles a circuit once and routes each partition to the best scoring backend. Native QONTOS-1 hardware joins as a fourth class at first module bring up, through the same ExecutorContract that already addresses the others.
IBM Quantum
Provider
Route partitions to Heron, Eagle, and Nighthawk processors through the QONTOS executor.
Amazon Braket
Provider
Multi device routing through AWS. The scheduler scores each device by fidelity, queue, and cost.
Qiskit Aer
Simulator
Local statevector and density matrix simulation. Same plan, same proof chain as native runs.
QONTOS-1 native
At gate G2
Native hardware joins through the same ExecutorContract at first module bring up.
Open source · Apache 2.0 · github.com/qontos See the platform →