quant-ph digest — 2026-04-23
Scored against Yuan's research programme (Y1–Y6):
- Y1 — arXiv:2502.09704 — iterative warm-started QAOA
- Y2 — arXiv:2304.06915 — quasi-binary portfolio QAOA
- Y3 — arXiv:2410.16265 — QAOA DGMVP portfolio (QST 2026)
- Y4 — arXiv:2603.14744 — Grover + ADMM cardinality-constrained BO
- Y5 — arXiv:2510.08292 — GW speed-ups via Gibbs states + Pauli sparsity
- Y6 — arXiv:2510.11213 — PBR test on IBM Heron2
Source
arXiv listing: https://arxiv.org/list/quant-ph/new (59 new + 18 cross = 77 entries; announce cycle Monday 20 April 2026)
Coverage: all 77 entries scored. 16 relevant (score ≥ 1); 61 SKIP (score 0, omitted).
Scoring rubric
0–10 on method/scope/conclusion overlap — max wins. HIGH 8–10 · MED 5–7 · LOW 1–4 · SKIP 0.
Highly relevant (score 8–10) — 2 papers
Quantum Search without Global Diffusion
- Authors: John Burke , Ciaran McGoldrick
- arXiv: 2604.15435
- Category: new submission — Quantum Physics (quant-ph) ; Data Structures and Algorithms (cs.DS)
- Score: 8/10 (HIGH)
- Overlaps with: Y4 (method)
- Why it matters: Quantum amplitude amplification with local diffusion, preserving Grover quadratic speedup. Direct method overlap with Y4 (Grover-based algorithm with O(sqrt(C(n,k)/M)) rotations for cardinality-constrained BO).
Quantum search is among the most important algorithms in quantum computing. At its core is quantum amplitude amplification, a technique that achieves a quadratic speedup over classical search by combining two global reflections: the oracle, which marks the target, and the diffusion operator, which reflects about the initial state. We show that this speedup can be preserved when the oracle is the only global operator, with all other operations acting locally on non-overlapping partitions of the search register. We present a recursive construction that, when the initial and target states both decompose as tensor products over these chosen partitions, admits an exact closed-form solution for th…
Overcoming the Lamb Shift in System-Bath Models via KMS Detailed Balance: High-Accuracy Thermalization with Time-Bounded Interactions
- Authors: Hongrui Chen , Zhiyan Ding , Ruizhe Zhang
- arXiv: 2604.15616
- Category: new submission — Quantum Physics (quant-ph)
- Score: 8/10 (HIGH)
- Overlaps with: Y5 (method)
- Why it matters: Quantum thermal state preparation via KMS detailed balance in weak coupling; unique fixed point close to the Gibbs state. Direct method overlap with Y5, whose core engine is Gibbs-state preparation for structured SDP relaxations.
We investigate quantum thermal state preparation algorithms based on system-bath interactions and uncover a surprising phenomenon in the weak-coupling regime. We rigorously prove that, if the system-bath interaction is engineered so that the transition part of the approximate Lindbladian generator satisfies the KMS detailed balance condition, then the unique fixed point of the dynamics can be made arbitrarily close to the Gibbs state in the weak-coupling limit, regardless of the structure of the Lamb shift term. Importantly, this remains true even when the approximate Lindbladian differs substantially from the ideal Davies generator and the Lamb shift term does not commute with the thermal s…
Moderately relevant (score 5–7) — 3 papers
Asymptotic optimality of Grover-Radhakrishnan-Korepin algorithm
- Authors: Kun Zhang , Kang-Yuan Chen , Xiao-Hui Wang , Vladimir Korepin
- arXiv: 2604.15886
- Category: new submission — Quantum Physics (quant-ph)
- Score: 7/10 (MED)
- Overlaps with: Y4 (method)
- Why it matters: Proves asymptotic optimality of the Grover-Radhakrishnan-Korepin partial-search algorithm — a close relative of Y4's structured Grover search over cardinality-k feasible sets.
Grover's algorithm is a cornerstone of quantum algorithms and is strictly optimal in oracle-query complexity. While the full search problem admits no further improvement, one may trade accuracy for speed in the partial search problem, where the task is to identify only the block containing the target item. The best known quantum algorithm for the partial search problem is the Grover-Radhakrishnan-Korepin (GRK) algorithm, whose optimality has long been conjectured but not proved. In this work, we prove the optimality of GRK in the large-block limit. We formulate partial search as a time-optimal control problem and apply the Pontryagin maximum principle to derive the switching-function dynamic…
Tensor Networks with Belief Propagation Cannot Feasibly Simulate Google's Quantum Echoes Experiment
- Authors: Pablo Bermejo , Benjamin Villalonga , Brayden Ware , Guifre Vidal , Aaron Szasz
- arXiv: 2604.15427
- Category: new submission — Quantum Physics (quant-ph)
- Score: 5/10 (MED)
- Overlaps with: Y3, Y5 (conclusion)
- Why it matters: Negative result on classical simulability of Google Quantum Echoes via tensor networks + belief propagation. Directly in the quantum-advantage vs dequantisation discourse that motivates Y3 (where thermal noise kills advantage) and Y5 (where quantum-inspired classical methods suffice).
In the recent quantum echoes experiment, Google Quantum AI showed that out-of-time-order correlators (OTOCs) for random-circuit time evolution can be measured using a quantum processor more than 10,000x faster than they can be computed to similar accuracy via classical computation. This claim was substantiated by comparison with a variety of state-of-the-art classical simulation methods. One classical simulation method that was not explicitly tested was tensor networks with belief propagation (TNBP). TNBP should be poorly suited to simulating Google's echoes experiment: the states involved are highly entangled, a challenge for tensor network states; and the Willow chip has dense 2D connectiv…
Observable-Guided Generator Selection for Improving Trainability in Quantum Machine Learning with a $ mathfrak{g} $-Purity Interpretation under Restricted Settings
- Authors: Hiroshi Ohno
- arXiv: 2604.15693
- Category: new submission — Quantum Physics (quant-ph)
- Score: 5/10 (MED)
- Overlaps with: Y5 (method)
- Why it matters: Observable-guided selection from n-qubit Pauli-string generator pools for parameterized unitaries — shares Y5's Pauli-sparsity philosophy (exploiting structure of Pauli-string Hamiltonians to pick tractable generators).
To study generator design for parameterized unitaries in quantum machine learning (QML), we propose an observable-guided generator selection algorithm for $ n $-qubit Pauli-string generator pools. The proposed method selects generators based on two criteria: maintaining large first-order sensitivity in the gradients and suppressing second-order interference in the Hessian matrix. Under a restricted setting with Pauli-string observables and candidate generators, the selection problem can be formulated as a binary optimization problem that favors mutually anti-commuting generators. Numerical experiments on a synthetic dataset with a small-scale five-qubit circuit show that the selected generat…
Tangential (score 1–4) — 11 papers
2604.15441 · score 4/10 · Quantum computation at the edge of chaos — Quantum sparsity principle for VQA trainability / barren plateaus — adjacent to the parameter/landscape questions in warm-started and layerwise QAOA (Y1, Y3). 2604.15432 · score 3/10 · Efficient $n$-qubit entangling operations via a superconducting quantum router — Efficient n-qubit entangling operations on a superconducting qubit router. Scope overlap with Y6's superconducting-hardware platform; no method/conclusion link. 2604.15603 · score 3/10 · A Game Theoretic Approach for Optimizing Quantum Error Budget Distribution — Game-theoretic optimization of fault-tolerant error-budget allocation — optimization-over-quantum-compilation, adjacent but orthogonal to optimization via quantum algorithms. 2604.15666 · score 3/10 · Explainable quantum regression algorithm with encoded data structure — Hybrid VQA with encoded data structure for explainability — tangential to VQA/QAOA ansatz design. 2604.15920 · score 3/10 · Local qubit invariants on quantum computer — Local qubit invariants measured on IBM Quantum Platform — experimental entanglement benchmarks on the same hardware family as Y6's PBR test. 2604.16179 · score 3/10 · Quantum-Inspired Simulation of 2D Turbulent Rayleigh-Bénard Convection — Quantum-inspired MPS simulation of turbulent convection — same "tensor-network as classical attack on quantum problems" lineage as Y5's dequantised SDP. 2604.15895 · score 2/10 · Digital Predistortion for Flux Control of Tunable Superconducting Qubits — Digital predistortion for flux control of tunable superconducting qubits — hardware-layer for the superconducting platform used in Y6. 2604.16144 · score 2/10 · Gravitationally induced wave-function collapse from dynamical bifurcation — Gravitationally induced wave-function collapse — foundations-of-QM bucket alongside the ontological status probed by Y6's PBR experiment. 2604.16276 · score 2/10 · Aziz and Howl's Gravity-Induced Entanglement Channel is Essentially Classical Mechanics — Re-examination of Aziz–Howl's gravity-induced entanglement channel — foundations-of-QM adjacency to Y6. 2604.16283 · score 2/10 · Boson correlations are spurious for classical states — Boson correlations are "spurious" Simpson-paradox effects for classical states — foundations / classical-vs-quantum reality, adjacent to Y6's ontic/epistemic theme. 2604.16292 · score 2/10 · Fast, High-Fidelity Erasure Detection of Dual-Rail Qubits with Symmetrically Coupled Readout — Fast erasure detection on dual-rail transmon qubits — superconducting-hardware scope only.
Summary table
| Score | arXiv ID | Short title | Overlaps | arXiv |
|---|---|---|---|---|
| 8 | 2604.15435 | Quantum Search without Global Diffusion | Y4 | link |
| 8 | 2604.15616 | Overcoming the Lamb Shift in System-Bath Models via KMS Detailed Bala… | Y5 | link |
| 7 | 2604.15886 | Asymptotic optimality of Grover-Radhakrishnan-Korepin algorithm | Y4 | link |
| 5 | 2604.15427 | Tensor Networks with Belief Propagation Cannot Feasibly Simulate Goog… | Y3,Y5 | link |
| 5 | 2604.15693 | Observable-Guided Generator Selection for Improving Trainability in Q… | Y5 | link |
| 4 | 2604.15441 | Quantum computation at the edge of chaos | Y1,Y3 | link |
| 3 | 2604.15432 | Efficient $n$-qubit entangling operations via a superconducting quant… | Y6 | link |
| 3 | 2604.15603 | A Game Theoretic Approach for Optimizing Quantum Error Budget Distrib… | Y3 | link |
| 3 | 2604.15666 | Explainable quantum regression algorithm with encoded data structure | Y3 | link |
| 3 | 2604.15920 | Local qubit invariants on quantum computer | Y6 | link |
| 3 | 2604.16179 | Quantum-Inspired Simulation of 2D Turbulent Rayleigh-Bénard Convection | Y5 | link |
| 2 | 2604.15895 | Digital Predistortion for Flux Control of Tunable Superconducting Qub… | Y6 | link |
| 2 | 2604.16144 | Gravitationally induced wave-function collapse from dynamical bifurca… | Y6 | link |
| 2 | 2604.16276 | Aziz and Howl's Gravity-Induced Entanglement Channel is Essentially C… | Y6 | link |
| 2 | 2604.16283 | Boson correlations are spurious for classical states | Y6 | link |
| 2 | 2604.16292 | Fast, High-Fidelity Erasure Detection of Dual-Rail Qubits with Symmet… | Y6 | link |