UCSB AI Lab Γ— UCSB Quantum CoDesign Lab β€” v0.5

Quantum's Last Question

From answering questions right to asking the right questions.

A two-stage pipeline that proposes research tasks and builds executable quantum environments for scientific agents.

RESEARCH
AGENT
Next Question
Literature
Review
Build ENV
Solve
Score
A blueprint for the next da Vinci β€” A Scientific Generalist AI.
0
human-written tasks
10+
live environments
0
frontier solves
42%
best agent progress

≀ 28 qubits Β· < 3 hours Β· one workstation Β· no quantum hardware

Research Begins With One Word.

01 / SEED Set the Direction A topic, method, phenomenon, or bottleneck β€” not a fully written research problem.
02 / DISCOVER Agent Finds the Gap QLQ searches the surrounding literature for unresolved directions that can become research tasks.
03 / VALIDATE Decide What Matters Judge novelty, validity, and whether the question is scientifically worth pursuing.

Your judgment is the gate.

Only accepted questions move forward.

Rejected questions are refined or regenerated before they become executable environments.

** Five or more accepted tasks earns authorship on our paper **

Domains

Nine seed subfields so far. We publish a sample of the live environments here β€” your field is welcome next.

Where the project stands

Five worked examples released. Complete task records and evaluation environments are now browsable end to end.
Call for reviewers opens. Quantum researchers across four continents are joining the expert-review stage.
Quantum control enters the benchmark. Two tasks now ask agents to reverse-engineer a numerically optimized flux-drive envelope and decide whether the optimizer rediscovered counterdiabatic driving.

What makes QLQ different

Reusable

More than a benchmark

Each environment can be reused to evaluate, train, and optimize scientific agents.

Auto-scored

No human grading

Each task ships as a runnable environment with a reference and a trivial baseline.

Contamination-resistant

Answers unknown

Questions are open at creation time. Nothing to memorize from training data.

Self-hardening

Difficulty scales

The setter diagnoses how the last agent won, then rebuilds the environment to close that shortcut.

Reproducible

Bounded by design

Tasks run on a single workstation under explicit compute, qubit, and time budgets.

Discovery-focused

Research, not recall

Measures the ability to propose and build a solution, not to retrieve a fact.

Samples from QLQ

Five complete examples, including the task, scorer, baselines, and solver trace.
Quantum metrology bench_metro2 Β· round 3 qiskit-aercpu8 qubits40 min

Variational design of noise-robust probe states via quantum Fisher information maximization

Seed topic: quantum metrology

Quantum metrology maximizes parameter-estimation precision, and the quantum Fisher information is the fundamental figure of merit. Prior work shows variational circuits can discover metrologically useful states under noise, but no compact, simulator-ready task isolates probe-state design under explicit depth and connectivity constraints. This one does.

An 8-qubit sensing model with collective-$Z$ generator $H=\sum_i Z_i$. A 4-layer hardware-efficient ansatz $V(\alpha)$ β€” RY then RZ on every qubit, then a ring of CZ entanglers β€” gives 64 trainable parameters. Phase encoding $U(\theta)=e^{-i\theta H}$ at working point $\theta_0=0$, followed by independent local dephasing with Kraus operators $K_0=\sqrt{1-p}\,I$, $K_1=\sqrt{p}\,Z$ at $p=0.10$.

Figure of merit
$$\max_{\alpha}\; F_Q\!\left(\rho_{\theta_0}(\alpha),\,H\right),\qquad |0\rangle^{\otimes 8}\xrightarrow{V(\alpha)}\xrightarrow{U(\theta_0)}\xrightarrow{\Lambda_p^{\otimes 8}}\rho_{\theta_0}(\alpha)$$

The harness exposes no black-box QFI oracle. The agent must build the circuit, apply the noise channel, and implement the mixed-state spectral QFI formula itself.

VALIDITY 1/1 NOVELTY 2/5 EXECUTABILITY 1/1
bar = progress from trivial to referenceraw score
trivial
0.0000
solver agent
11.0022
reference
29.4603

Best of 3 blind attempts reached 37% of the way from the trivial baseline to the reference. Direction: maximize. One evaluation costs 0.8 s against a 2400 s budget.

Hamiltonian simulation bench_ham1 Β· round 3 qiskit-aercpu10 qubits20 min

Low-depth digital Hamiltonian simulation for a fixed 1D spin chain via circuit design

Seed topic: Hamiltonian simulation

Design a shallow quantum circuit that approximates fixed-time evolution under a standard 1D spin Hamiltonian within near-term depth constraints, and optimize it for simulation fidelity on a simulator. Practically relevant, with a clear metric and no hardware access.

The hidden instance is a transverse-field Ising chain deliberately skewed so that interaction terms dominate β€” invalidating the near-symmetric angle schedules that generic QAOA/Trotter ansΓ€tze fall back on. Fidelity is averaged over a 24-state XZ-product ensemble to prevent overfitting to a single basis.

Figure of merit
$$H=-J\sum_i Z_iZ_{i+1}-h\sum_i X_i,\qquad J=1.0,\;h=0.35,\;t=2.3$$ $$\min\;\mathcal{L}=1-\overline{\left|\langle\psi_k|\,C^{\dagger}e^{-iHt}\,|\psi_k\rangle\right|^{2}}$$

A first-order Trotter step with unscaled angles gives $\mathcal{L}\approx0.33$; the tuned depth-4 brickwork reference reaches $\approx0.08$.

VALIDITY 1/1 NOVELTY 2/5 EXECUTABILITY 1/1
bar = progress from trivial to referenceraw score
trivial
0.9989
solver agent
0.7630
reference
0.4385

Best of 3 blind attempts reached 42% of the way from the trivial baseline to the reference β€” the highest any agent has managed on this benchmark. Direction: minimize. One evaluation costs 0.6 s against a 1200 s budget.

Hamiltonian simulation bench_ham2 Β· round 3 qiskit-aercpu10 qubits30 min

Learning entanglement-aware Trotter step allocation for 1D spin-chain Hamiltonian simulation

Seed topic: Hamiltonian simulation

Product-formula methods still dominate practical simulation on NISQ and early fault-tolerant devices, yet rigorous step-number bounds are worst-case and vastly overestimate resources. Recent theory shows Trotter error can scale with entanglement and commutator structure rather than system size β€” but these bounds are hard to exploit instance by instance.

The task asks for a classical learning-based policy that, given a fixed 1D spin-chain Hamiltonian and target time, outputs a non-uniform allocation of Trotter steps across local terms and time slices, minimizing the actual simulation error measured on an exact statevector simulator within a strict qubit budget.

Figure of merit
$$\min\;\tfrac{1}{2}\left\|\,\rho_{\text{exact}}-\rho_{\text{Trotter}}\,\right\|_1 \quad\text{s.t.}\quad \textstyle\sum_j r_j \le R_{\max}$$

Trace distance between the true and simulated states under a fixed total gate budget $R_{\max}$, allocated non-uniformly across terms.

VALIDITY 1/1 NOVELTY 4/5 EXECUTABILITY 1/1
bar = progress from trivial to referenceraw score
trivial
0.9962
solver agent
0.9994
reference
0.2713

Unsolved. The best of 3 blind attempts scored worse than the trivial baseline β€” the most novel task in the set, and no agent has moved it at all. Direction: minimize. One evaluation costs 6.5 s against a 1800 s budget.

Quantum control flux_iswap_1 Β· round 1 qiskit-aercpu3 qubits150 min

Reverse-engineering the learned control strategy in a numerically-optimized parametric flux-driven iSWAP gate

Seed topic: Reverse-engineering learned control strategies in parametric flux-driven iSWAP gates on asymmetric-SQUID tunable couplers

An expert supplied a numerically optimized flux-drive envelope $e(t)$ β€” 105 points at 0.5 ns, 52 ns total β€” for a parametric iSWAP gate between two fixed-frequency transmons coupled through an asymmetric-SQUID tunable coupler. The optimizer produced a pulse whose shape carries non-white structure: asymmetric rise/fall (6.0 ns vs 5.5 ns), a drooping plateau ($-0.75\times10^{-3}$ per ns), and a structured residual ripple (lag-1 autocorrelation $+0.587$, spectral flatness $0.147$) peaking near 0.66 GHz β€” within frequency resolution of $(f_{q1}-f_{q2})-\alpha_2 = 0.668$ GHz.

The research question: did the optimizer discover a control practice that is not analytically obvious? The task treats each measured feature as a falsifiable hypothesis and asks whether it corresponds to a known mechanism β€” counterdiabatic ($\Phi$-DRAG-type) leakage cancellation, AC-Stark phase compensation, or Floquet-engineered sideband cancellation.

Figure of merit
$$\text{score} = 0.30\,s_{\text{stats}} + 0.35\,s_{\text{abl}} + 0.20\,s_{\text{side}} + 0.15\,s_{\text{cd}}$$

Decomposition statistics, causal ablation leakage via 27-dimensional Hamiltonian propagation, sideband-resonance argmin, and the counterdiabatic agreement metric.

VALIDITY 1/1 NOVELTY 4/5 EXECUTABILITY 1/1
bar = progress from trivial to referenceraw score
trivial
0.4712
solver agent
0.5324
reference
0.9100

Best of 3 blind attempts reached 14% of the way from the trivial baseline to the reference. Direction: maximize. One evaluation costs 5.3 s against a 9000 s budget.

Quantum control flux_iswap_2 Β· round 1 qiskit-aercpu9 qubits150 min

Is the structured plateau ripple an effective counterdiabatic / flux-DRAG leakage-suppression term?

Seed topic: Reverse-engineering learned control strategies in parametric flux-driven iSWAP gates on asymmetric-SQUID tunable couplers

The same envelope, attacked from the other side. Two literatures suggest the structure is not an artifact: effective counterdiabatic driving can be absorbed as high-frequency modulation of the existing control field at frequencies set by inter-level gaps, and flux-tuned DRAG ($\Phi$-DRAG) supplies an analytic leakage-suppression correction unique to flux rather than microwave control.

The agent must build the three-transmon circuit-QED model ($f_{q1}=5.163$ GHz, $f_{q2}=4.678$ GHz, $\alpha_1=-0.200$ GHz, $\alpha_2=-0.183$ GHz), propagate the 105-point envelope in a 27-dimensional Hilbert space, reconstruct the effective iSWAP exchange rate $J_{\text{eff}}$ from a Bessel-sideband effective Hamiltonian, and run a pre-registered ablation study that notches out the 0.66 GHz component, symmetrizes the ramps, and removes the droop.

Figure of merit
$$\text{verdict}_X=\frac{\overline{|\,\text{infid}_{\text{ablate}(X)}-\text{infid}_{\text{base}}\,|}}{\overline{|\,\text{infid}_{\text{white}}-\text{infid}_{\text{base}}\,|}}$$

Each envelope feature is classified functional or inert against a matched-variance white-noise null model. Six scored components; total error is minimized.

VALIDITY 1/1 NOVELTY 4/5 EXECUTABILITY 1/1
bar = progress from trivial to referenceraw score
trivial
6.7524
solver agent
4.9543
reference
0.0321

Best of 3 blind attempts reached 27% of the way from the trivial baseline to the reference. Direction: minimize. One evaluation costs 55.2 s against a 9000 s budget.

1 / 5

Full chain for every task β€” seed, proposal, AI review, scorer source, and the solving agent's attempts β€” is browsable in the worked examples.

Results

TaskDomainTrivial Solver agentReference Progress ↑Novelty
bench_ham1Hamiltonian simulation0.99890.76300.438542%2/5
bench_metro2Quantum metrology0.000011.002229.460337%2/5
flux_iswap_2Quantum control6.75244.95430.032127%4/5
flux_iswap_1Quantum control0.47120.53240.910014%4/5
bench_ham2Hamiltonian simulation0.99620.99940.27130%4/5

Five of the live environments with published traces Β· Solver agent: best of 3 blind attempts Β· Progress normalized so trivial = 0% and reference = 100% Β· Novelty scored 1–5 by an independent reviewing agent (5 = original)

Leaderboard

Frontier models, average progress across live environments: trivial baseline (0%) to reference solution (100%).

No model is near the human best on QLQ.

Average progress across live environments. Preliminary placeholder scores β€” full evaluation in progress.

Claude Opus 4.8 Β· Anthropic3.4%
GPT-5.5 Β· OpenAI2.1%

Contributors

Core contributors
Zhaotian Weng
Zhaotian Weng*
UC Santa Barbara
Gurusha Juneja
Gurusha Juneja*
UC Santa Barbara
Jonah So
Jonah So*
UC Santa Barbara

*Equal contribution.

Advisory committee
Xin Eric Wang
Xin Eric Wang
UC Santa Barbara Β· AI Lab
Multimodal AI and language agents
Murphy Niu
Murphy Yuezhen Niu
UC Santa Barbara Β· Quantum CoDesign Lab
Quantum machine learning and quantum control
Reviewing researchers

673 quantum researchers across four continents have been invited. Confirmed reviewers will be listed here by name, with institutional affiliations, ahead of publication.

1UC Santa Barbara
Contributing institutions
UC Santa Barbara
Google DeepMind

FAQ

If an AI writes the problems, aren't they easy or meaningless?+
Difficulty is visible in the published solver traces and baselines. Scientific meaningfulness is different: that is the part a program cannot certify, so expert review remains a gate before a proposed question enters the benchmark.
Is this only about quantum science?+
No. The claim β€” that an agent can select its own research question and build the environment to answer it β€” is not specific to quantum. Quantum is where we start because it is one of the few fields where an agent-invented environment can actually be run and scored: the physics is simulable and the answer is checkable, with no wet lab in between. The environments this produces are meant to be reused β€” to evaluate, train and optimize AI scientists at a scale hand-built benchmarks do not reach.
What does reviewing involve?+
You review four generated questions: two from your own research direction and two from another researcher's seed. Judge whether each is open, valid, well-posed, meaningful, and worth solving. You can request regeneration, and a completed example is provided before you start. No coding is required.
How are contributors compensated?+
Every reviewer is acknowledged by name in the publication. Contribute five or more accepted tasks and your name is added to the author list.
Who can contribute?+
Any working quantum researcher β€” faculty, postdocs, PhD students, and industry scientists. You review problems in your own area of expertise.
Do I need quantum hardware to run these tasks?+
No. Every task in the benchmark is written to run on a single workstation: at most 28 qubits, under three hours of compute, simulator only. This is a deliberate constraint β€” it keeps the benchmark reproducible by anyone and keeps the difficulty in the physics rather than in the hardware access.
Are the scores on this page verified?+
The validity, novelty and executability scores are machine judgments awaiting expert verification β€” that verification is exactly what we are recruiting for. The performance numbers (trivial, solver, reference) are measured directly by the evaluation harness and are not judgments.
Call for reviewers

Shape the future of scientific agents.

Bring your field into the loop.

Questions or feedback: zhaotian@ucsb.edu Report a broken task: zhaotian@ucsb.edu