quant-ph digest — 2026-05-04
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 (41 new + 13 cross = 54 entries)
Coverage: all 54 entries scored. 7 relevant (score ≥ 1); 47 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) — 1 paper
A Resource-Efficient Variational Quantum Framework for the Traveling Salesman Problem
- Authors: Yuefeng Lin, Chao Zheng, Cong Guo
- arXiv: 2605.00739
- Category: new submission — Quantum Physics (quant-ph)
- Score: 8/10 (HIGH)
- Overlaps with: Y2 (method — compact encoding + feasibility-preserving mixer), Y4 (scope — constrained combinatorial optimization with structured feasible space), Y3 (scope — NISQ variational optimization with measurement-error mitigation)
- Why it matters: This is a TSP analogue of Y2's quasi-binary-encoding-plus-hard-mixer playbook:
M⌈log2 M⌉data qubits per problem after cyclic-symmetry reduction, with a permutation-preserving ansatz built from ancilla-controlled register-SWAPs that never leaves the feasible tour subspace (so penalty terms can be dropped from the variational objective). On 4–6 city benchmarks it beats a one-hot feasible-subspace baseline by up to 37 percentage points; the divide-and-conquer engine then runs a 5-city instance on a 2-qubit NMR processor.
The Traveling Salesman Problem (TSP) is a prototypical combinatorial optimization problem, but its quantum implementation is limited by the O(n2)-qubit overhead of standard one-hot encodings. Here, we propose a resource-efficient variational quantum framework based on compact binary-register encoding, a permutation-preserving problem-inspired ansatz, and a complementary divide-and-conquer execution strategy. The compact encoding reduces the data-qubit requirement to O(n log n), while the divide-and-conquer formulation lowers the number of qubits required in each local hardware execution to the size of the largest subsystem. Numerical simulations on TSP instances with 4, 5, and 6 cities achieve best average success rates of 100%, 100%, and 95.5%, respectively. A local two-qubit implementation of the divide-and-conquer approximation is further evaluated for a 5-city TSP instance on SpinQ Gemini Pro and SpinQ Triangulum II NMR quantum computers.
Moderately relevant (score 5–7) — 3 papers
Quantum Decoding Algorithms: Quantum Speedups in Optimization
- Authors: Jan Ljubas, Tim Byrnes
- arXiv: 2605.00312
- Category: new submission — Quantum Physics (quant-ph)
- Score: 7/10 (MED)
- Overlaps with: Y3 (conclusion — quantum advantage for optimization), Y4 (conclusion — structured-problem speedups, coding-theoretic adjacency to Y4's Grover-on-feasible-set construction)
- Why it matters: Self-contained review of Decoded Quantum Interferometry (DQI) — a coding-theoretic / interferometric algorithm with strong evidence of superpolynomial speedup on the Optimal Polynomial Intersection (OPI) instance of max-LINSAT. This is the algorithmic family Yuan's QAOA / Grover papers compete against in the broader "quantum speedup for combinatorial optimization" arena, and a clean review is useful for situating Y3/Y4 in their landscape.
Attaining a quantum speedup in solving practically useful optimization problems has been one of the holy grails in the field of quantum computing. While prior approaches have demonstrated speedups for certain structured problem classes, establishing a clear and scalable advantage on broadly useful practical optimization problems remains challenging. Recently, a new approach to solving the max-LINSAT class of optimization problems has emerged, called Decoded Quantum Interferometry (DQI). In DQI, a combination of techniques rooted in (classical) coding theory and interferometry are used to obtain the solution of max-LINSAT. In the special problem instance of the optimal polynomial intersection (OPI) problem, strong evidence exists to show that an superpolynomial speedup exists over the best classical methods in obtaining an approximate solution.
Toward Secure Multitenant Quantum Computing: Circuit Affinity, Crosstalk Patterns, and Grouping Strategies
- Authors: Andrew Woods, Chi-Ren Shyu
- arXiv: 2605.00118
- Category: new submission — Quantum Physics (quant-ph)
- Score: 6/10 (MED)
- Overlaps with: Y6 (scope — IBM Heron / superconducting hardware), Y3 (scope — QAOA on real NISQ noise), Y4 (scope — Grover circuits as workload)
- Why it matters: Empirical crosstalk characterization across seven IBM superconducting processors — Heron r1–r3 and Nighthawk r1, the same Heron family used in Y6's PBR experiment — using QAOA, Grover, QPE, QFT, and ZZFeatureMap as the workload set. Quantifies how concurrent jobs distort QAOA/Grover-style circuits on the very devices Yuan is publishing on; relevant prior reading for any future Heron-based experimental run.
Multitenancy increases throughput and reduces costs in cloud-based quantum computing, but concurrent job execution introduces security risks through inter-circuit crosstalk. We characterize the structural predictability of these interference patterns across seven IBM superconducting processors, spanning Heron (r1-r3) and Nighthawk (r1) architectures and five different circuit types. We evaluate pairwise interactions, by applying the Structural Similarity Index (SSIM) and a structural t-statistic to the concurrent execution of five foundational quantum circuits (QAOA, Grover's, QPE, QFT, and ZZFeatureMap), we quantify behavioral consistency across disparate hardware. Crosstalk signatures are highly consistent within architectural revisions — intra-revision similarity reaching 0.77 (Hr3) and 0.68 (Hr2) — while inter-revision similarity drops to 0.43.
Measuring the largest coefficients of a quantum state
- Authors: Nicolás Ciancaglini, Santiago Cifuentes, Guido Bellomo, Santiago Figueira, Ariel Bendersky
- arXiv: 2605.00341
- Category: new submission — Quantum Physics (quant-ph)
- Score: 6/10 (MED)
- Overlaps with: Y5 (method — Pauli-sparse representations and structured-Pauli reasoning)
- Why it matters: A best-first prefix-tree algorithm that uses Bell sampling on two state copies (or SWAP tests) to find the largest Pauli coefficients of an unknown n-qubit state, with sample-complexity bounds parameterised by purity. Same Pauli-sparsity premise that underwrites Y5's Gibbs-state SDP relaxations — useful as a state-side characterization tool to complement Y5's Hamiltonian-side sparsity exploitation.
We introduce a hierarchical algorithm for identifying the largest Pauli coefficients of an unknown n-qubit quantum state. The algorithm traverses a prefix-based tree whose nodes represent partial sums of squared Pauli coefficients, always expanding branches with the largest estimated weight and discarding the rest. Node weights are estimated using Bell sampling on two copies of the state, or alternatively via SWAP tests on subsystems. We analyze the sample complexity of each node estimation and derive bounds on the total number of nodes expanded as a function of the desired number of coefficients and the state's purity. For states admitting a sparse representation in the Pauli basis, the algorithm achieves a good reconstruction of the dominant components without requiring full state tomography.
Tangential (score 1–4) — 3 papers
- 2605.00807 · score 4/10 · Probability Distribution Analysis of the Cascaded Variational Quantum Eigensolver — CVQE with trapezoidal guiding-state selection; "guiding state" choice is a deterministic warm-start cousin of Y1's measurement-derived warm-starting, on a chemistry rather than combinatorial problem.
- 2605.00626 · score 2/10 · Learning Lindblad Dynamics of a Superconducting Quantum Processor — LIMINAL framework for selecting minimal Lindblad models on a 5-qubit superconducting processor; same hardware family as Y6, narrower in scope (model selection rather than foundational test).
- 2605.00406 · score 2/10 · Bell Correlations and Selection Bias — argues Bell correlations are selection artefacts rather than evidence of nonlocality; PBR-adjacent foundations, very different argument from Y6's hardware-based ontic/epistemic test.
Summary table
| Score | arXiv ID | Short title | Overlaps | arXiv |
|---|---|---|---|---|
| 8 | 2605.00739 | Resource-efficient variational quantum framework for TSP | Y2, Y4, Y3 | link |
| 7 | 2605.00312 | Quantum decoding algorithms: speedups in optimization (DQI review) | Y3, Y4 | link |
| 6 | 2605.00118 | Multitenant QC crosstalk on IBM Heron / Nighthawk | Y6, Y3, Y4 | link |
| 6 | 2605.00341 | Measuring the largest Pauli coefficients of a quantum state | Y5 | link |
| 4 | 2605.00807 | Probability distribution analysis of cascaded VQE | Y1, Y3 | link |
| 2 | 2605.00626 | Learning Lindblad dynamics of a superconducting QPU | Y6 | link |
| 2 | 2605.00406 | Bell correlations and selection bias | Y6 | link |