Neutral-atom analogue simulator (Rydberg arrays, lattice gases) on the map bar: Analogue atom simulator

The architecture in the report (§8.3)

8.3.9 Analogue atom simulator — Neutral-atom analogue simulator (Rydberg arrays, lattice gases) (atom_analog)

The idea. Keep the alkali tweezer array with its lasers, transport and imaging; drop the gate: global Rydberg lasers drive the whole register under one Ising Hamiltonian, Analogue Rydberg Hamiltonian evolution (g_rydanalog) on the Ground–Rydberg analogue qubit (enc_gr). Waveforms Ω(t), Δ(t) and atom geometry are the program, a bit-string snapshot the output. The bet: for many-body physics (G1), native Hamiltonian evolution reaches hundreds of atoms now. It gives up memory, gates and any route to fault tolerance.

What it needs. The evolution requires the ground–Rydberg basis, a Rydberg level in the carrier and global Rydberg lasers; imaging, an imaging transition. Code, decoder and interconnect are empty by design (§7.6): here analogue simulation stops being a quantum computer in the register's sense. The encoding is a basis, not a memory: |r⟩ cannot be shelved; Aquila's T2 is 5.8 µs, programs stop at 4 µs [C][262]; errors integrate coherently with no instant for a syndrome, so no code attaches and no decoder has input. Without an entangling gate they are devices, not processors (Table 8.3 prints no gate-capable size, no two-qubit error). The one replaces* edge swaps the species.

Where it stands. Three machines, three devices, none gate-capable. Aquila (QuEra, 256 ⁸⁷Rb atoms, on Amazon Braket since November 2022) [C][262] carries the physics: (2+1)D string breaking in a gauge theory, no advantage claim [D][226]. Fresnel / Fresnel 2 (Pasqal, deployed 2023–2024) publishes no error rates. QUIONE (ICFO, April 2024) images an ⁸⁴Sr quantum gas site by site in an 813.4 nm lattice, fidelity above 94% [D][263]. §7.4's T2 for the architecture is the ground–Rydberg qubit's own 11.4 µs (Aquila, spin echo) [C][262] since 26 Sep 2026, no longer the carrier's 12.6-s caesium hyperfine record [138], [139], which a qubit with a Rydberg level cannot use. 25 of 33 cells documented. No machine postdates 2024; the vendors' later ones (Gemini-class, Libra, Orion, Vela) are gate-model.

Exceptions and borrowings. The dual-mode Pasqal machines mirror each other: Fresnel / Fresnel 2 runs analogue as primary, its digital mode (Hyperfine / clock-state qubit, Rydberg-blockade CZ) and PIC-generated tweezers as alternates; Orion Alpha / Beta ("Ruby") / Gamma, on the alkali architecture, swaps the modes; all else matches. Each fits its own architecture seven technologies to five: the boundary with atom_rb is a mode switch in layers 2–3 of one hardware (hybrid). The gate separates simulator from processor; the line fault tolerance needs, a code, neither has crossed. QUIONE lacks encoding, gate and Rydberg state: a Bose–Hubbard gas in a lattice (∅G-lattice, shared with MAQCS) under a carrier named for erasure-native tweezer qubits, here by elimination (four technologies in slot): the architecture is too narrow for lattice quantum-gas simulators. Caltech's erasure-excising Sr Rydberg simulator [143], which the new alkaline-earth edges describe, is not in the register.

The next test. Two expectations; §5.2 has no analogue row. Confirmation: by 31 December 2027 a commercial analogue machine publishes a many-body fidelity at 60 or more atoms or a T2* above 20 µs, or an analogue result survives a year of classical challenge (§2.8). Demotion: if Vela and QuEra's next systems ship without analogue specifications and no analogue-first machine is announced by mid-2027, analogue simulation is a mode, analogue alternates of layers 2–3 on atom_rb, not an architecture.

What the builders say. Pasqal runs analogue workloads today on hardware it designs to evolve toward fault tolerance [C][157]. In June 2025 it promised a 250-qubit processor built for quantum advantage on an industry problem, to be demonstrated in the first part of 2026 [R][166], [167]. In September 2026 it reported simulating materials beyond the practical reach of classical computing [C][157]: 256 atoms on Orion Beta reproduced the magnet TmMgGaO₄, checked against crystal measurements [P][848]. QuEra says real-time gauge-theory dynamics with dozens of qubits on Aquila reach the limits of classical simulation [C][849]. ICFO's case for QUIONE: quantum simulation can answer questions current computers cannot, such as why some materials conduct without loss at relatively high temperatures [C][850].

Machines of this architecture (register: 3, of them 3 devices, 0 gate-capable). ICFO - Institut de Ciencies Fotoniques — QUIONE (demonstrated); Pasqal — Fresnel / Fresnel 2 (deployed, 100); QuEra — Aquila (deployed, 256).

Cells outside the architecture's slots (4). QUIONE: L4 ∅G-lattice (Atlas gap — atoms held in a 2-D in-plane optical lattice plus light sheet at 813.4 nm; no per-atom mov); Fresnel / Fresnel 2: L2 Hyperfine / clock-state qubit (enc_hf, alternate borrowed from another architecture); Fresnel / Fresnel 2: L3 Rydberg-blockade CZ (g_ryd, alternate borrowed from another architecture); Fresnel / Fresnel 2: L5 PIC-generated tweezers / integrated optics for atoms (ct_pic_trap, alternate borrowed from another architecture).