quant-ph digest — 2026-05-20
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 (100 new + 26 cross = 126 entries)
Coverage: all 126 entries scored. 15 relevant (score ≥ 1); 111 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) — 4 papers
A Penalty-Free Pipeline for Direct Quantum-Annealer Portfolio Optimization
- Authors: Luis Lozano
- arXiv: 2605.17628
- Category: new submission — Quantum Physics (quant-ph); Optimization and Control (math.OC); Portfolio Management (q-fin.PM)
- Score: 10/10 (HIGH)
- Overlaps with: Y2 (method: no-penalty), Y3 (scope: cardinality portfolio), Y4 (scope: cardinality BO)
- Why it matters: Closest method-level match to Yuan's Y2 in today's batch: independently identifies the cardinality penalty as the structural bottleneck on D-Wave hardware and removes it via classical post-processing. Drops chain-break fractions from 71–92% to ≤ 0.04% on Pegasus / Zephyr at FF49 scale. Direct empirical validation of Y2's design choice from another author on the annealer side.
Direct quantum-annealer portfolio optimization is commonly formulated as a penalty-encoded QUBO and submitted to D-Wave hardware. We show that this standard formulation fails on current devices and identify the structural reason: the cardinality penalty contributes a dense rank-one term proportional to the all-ones matrix that makes the logical interaction graph complete regardless of the covariance structure. On Pegasus and Zephyr, chain-break fractions reach 83 percent at N equal to 24 and 92 percent at N equal to 49, producing no feasible samples. Attempting to fix this through topology-aware sparsification reveals a second problem: any sparsifier that removes off-diagonal entries also…
Where the Quantum Lives in D-Wave Hybrid Portfolio Optimization
- Authors: Luis Lozano
- arXiv: 2605.17623
- Category: new submission — Quantum Physics (quant-ph); Optimization and Control (math.OC); Portfolio Management (q-fin.PM)
- Score: 9/10 (HIGH)
- Overlaps with: Y3 (scope: portfolio benchmark), Y4 (scope: cardinality-constrained), Y2 (method: constraint-native)
- Why it matters: Quantum-classical decomposition audit of D-Wave's hybrid portfolio-optimization service: only 0.034 s of QPU time out of a 5 s wall-clock budget (~0.7%). The rest is classical decomposition. Companion to 2605.17628; together they triangulate the same diagnosis as Y3 from the annealer side. Anchored against Gurobi MIQP on N up to 640.
We audit how much of D-Wave's hybrid quantum-classical portfolio-optimization service is actually quantum. On cardinality-constrained mean-variance-turnover instances spanning N equal to 10 to 640 with a Gurobi MIQP optimality anchor, the constraint-native LeapHybridCQM service matches Gurobi's proven optimum on all 54 instances where Gurobi proves optimality, but the mean QPU access time is only 0.034 seconds out of a 5-second wall-clock budget, roughly 0.7 percent of the run. The remaining roughly 99 percent is the service's classical decomposition, sub-problem assembly, and feasibility-aware reassembly, so the reported D-Wave hybrid win on this problem class is a constraint-native…
Truncated-Binary Encoding: Spectral Degree Reduction of Combinatorial Optimization Problems for Quantum Hardware
- Authors: Tristan Zaborniak
- arXiv: 2605.17143
- Category: new submission — Quantum Physics (quant-ph)
- Score: 9/10 (HIGH)
- Overlaps with: Y2 (method: encoding for QAOA), Y1 (method: warm-start basin analysis)
- Why it matters: Proposes truncated-binary encoding (TBE): drops Walsh monomials of degree > k_max from the exact-binary HUBO, with a tight L∞ error bound and basin-preservation guarantees. Same compilation layer as Y2's quasi-binary encoding but follows the orthogonal axis (approximation quality vs. constraint preservation). The Ising-basis Walsh-spectral framework is reusable in any future Y2 extension.
Exact-binary encoding compiles a discrete cost function network (CFN) into a higher-order unconstrained binary optimization (HUBO) problem whose maximum monomial degree grows with the cardinalities of the underlying CFN variables. Given that quantum optimization hardware generally favours quadratic unconstrained binary optimization or low-degree HUBO Hamiltonians, high-cardinality CFNs therefore incur substantial overhead in the form of circuit depth, or ancilla qubits when degree-reduction techniques are employed. To ameliorate these issues, we propose \textit{truncated-binary encoding} (TBE): a modification of exact-binary encoding in which Ising-basis monomials exceeding a chosen cutoff…
Quantum Model for CVRPTW
- Authors: Imran Meghazi (LIRMM), Éric Bourreau (LIRMM)
- arXiv: 2605.18393
- Category: cross submission — Optimization and Control (math.OC); Quantum Physics (quant-ph)
- Score: 8/10 (HIGH)
- Overlaps with: Y4 (method: Grover Adaptive Search on structured feasible space)
- Why it matters: First Grover Adaptive Search oracle formulation of CVRPTW. Uses Beasley's split-procedure-inspired encoding to add only n decision qubits over standard quantum TSP. Reusable comparator + conditional-encoder subcircuits for any future Y4 extension to multi-constraint feasible spaces. 147-qubit estimate for 6-customer instances is a concrete FT-era resource anchor.
This paper proposes a quantum algorithm for the capacitated vehicle routing problem with time windows (CVRPTW) based on Grover Search framework. This problem is often faced by Postal services in the context of package delivery or other time-sensitive operations. We provide an implementation on gate based quantum computer of a model inspired by classical route first, cluster second technique. The quantum paradigm allows to overcome suboptimality inherent property of this decomposition. In the current NISQ (Noisy Intermediate-Scale Quantum) era, the most important limitation is the number of available qubits which makes time windows and capacity constraints hard to tackle. We introduce a…
Moderately relevant (score 5–7) — 7 papers
Scaling Quantum Optimization for Unit Commitment via Pauli Correlation Encoding
- Authors: Kien X. Nguyen, Ilya Safro, Xiaoyuan Liu
- arXiv: 2605.17145
- Category: new submission — Quantum Physics (quant-ph)
- Score: 7/10 (MED)
- Overlaps with: Y2 (method: qubit-efficient encoding of binary decision variables)
- Why it matters: Hybrid quantum-classical method for unit commitment using Pauli-Correlation Encoding to handle 312 binary variables with far fewer qubits than one-per-variable. Same qubit-efficiency motivation as Y2's quasi-binary encoding but applied to power-systems scheduling. Leader-follower (quantum then classical) structure.
Unit commitment is an important optimization problem in power system operations, classified as NP-hard. This paper presents a hybrid quantum-classical method for the unit commitment problem with time-dependent constraints, where decisions must be made about which generators to turn on/off and how much power they should produce over a planning horizon. We use a hybrid quantum-classical optimization procedure to determine the on/off schedules of the generating units and the corresponding power dispatch that satisfies operational constraints such as load balance, generator limits, ramping, and reserve requirements. We frame the optimization loop as a leader-follower structure, where the…
From Constraint to Code: DQI-Kit -- A Software Framework for Decoded Quantum Interferometry
- Authors: Simon Thelen, Wolfgang Mauerer
- arXiv: 2605.16955
- Category: new submission — Quantum Physics (quant-ph)
- Score: 6/10 (MED)
- Overlaps with: Y2 (method: encoding transformations for constrained optimization)
- Why it matters: DQI-Kit: software framework for encoding constrained optimization problems into Max-LINSAT for Decoded Quantum Interferometry. Same compilation-layer motivation as Y2 / TBE — automating the transformations that bridge domain objectives and quantum-algorithm-compatible formats. DQI is an emerging algorithm with claimed advantage on algebraic optimisation.
Trying to solve hard optimisation problems with quantum techniques requires transformations of domain objectives and constraints into formats compatible with a chosen quantum algorithm. This often introduces inefficiencies and overheads that limit or even endanger potential quantum advantage for current and future approaches. To understand and mitigate these inefficiencies, software toolchains are essential for implementing transformations, analysing overheads and eventually selecting optimal transformation paths. Decoded Quantum Interferometry (DQI) is a novel approach that achieves apparent quantum advantage for certain algebraic optimisation problems. It natively operates on Max-LINSAT,…
Efficient Hamiltonian Engineering for Adiabatic MIS Algorithms
- Authors: Guy Karni, Noam Cohen, Adi Pick
- arXiv: 2605.16944
- Category: new submission — Quantum Physics (quant-ph)
- Score: 6/10 (MED)
- Overlaps with: Y3 (scope: NISQ combinatorial optimization on hardware)
- Why it matters: Hybrid adiabatic algorithm for Maximum Independent Set on Rydberg atom arrays. Engineers local controls that preferentially excite low-degree nodes. 25% reduction in fidelity decay rate as problem hardness grows. NISQ-era constrained combinatorial optimization on a different hardware substrate to Yuan's Y3 (QAOA).
We present a hybrid adiabatic algorithm for maximum independent set (MIS) using Rydberg atom arrays. We engineer local controls that preferentially excite atoms with few neighbors, which represent graph nodes with small degrees. Numerical simulations show that the designed pulses accelerate convergence to the MIS state and suppress population in trap states. We obtain higher success probabilities than traditional global controls and a $25\%$ reduction in fidelity decay rate as problem hardness increases.
Schedule-dependent basin occupation in a programmable quantum annealer
- Authors: Luis Lozano
- arXiv: 2605.17604
- Category: new submission — Quantum Physics (quant-ph); Disordered Systems and Neural Networks (cond-mat.dis-nn)
- Score: 6/10 (MED)
- Overlaps with: Y3 (scope: annealing-based combinatorial optimization, noise-regime benchmarking)
- Why it matters: Schedule-dependent basin occupation in cycled reverse annealing on D-Wave Advantage2 / Advantage6.4 for mixed-frustration 12-qubit Ising. Brackets between localized parallel tempering and delocalized PIQMC — schedules act as instance-specific basin-occupation probes rather than universal enhancement knobs. Revises prior two-pause-enhancement claims.
On a mixed-frustration 12-qubit Ising instance (seed 14029) run on two D-Wave generations, Advantage2 Zephyr and Advantage_system6.4 Pegasus, the late-time subsystem autocorrelation under cycled reverse annealing sits strictly between two equilibrium reference processes at the device-calibrated effective temperature: localized parallel tempering, and delocalized equilibrated path-integral simulated quantum annealing at a fixed Advantage2 pause-point transverse-field scale. The bracket holds on all three tested schedules and at both hardware calibrations. We obtain this result through two ingredients: a cycled reverse-anneal protocol (reinitialize_state=False, 50 cycles per submission) used…
An Entropy-Governed Speedup for Quantum Algorithms on Local Hamiltonians
- Authors: Ranitha Mataraarachchi (1), François Le Gall (1), Suguru Tamaki (2) ((1) Nagoya University, Japan, (2) University of Hyogo, Japan)
- arXiv: 2605.18241
- Category: new submission — Quantum Physics (quant-ph); Computational Complexity (cs.CC); Data Structures and Algorithms (cs.DS)
- Score: 6/10 (MED)
- Overlaps with: Y4 (method: Grover-bound improvement for structured Hamiltonians)
- Why it matters: Faster quantum algorithm for low-energy estimation / state preparation on k-local Hamiltonians, breaking the natural Grover O(2^(n/2)) bound for depth-d states. Method-level adjacency to Y4's Grover-with-structure approach (here the structure is the depth-d state class, in Y4 it is the C(n,k) feasible set).
Low-energy estimation and state preparation for general $k$-local Hamiltonians are fundamental challenges in quantum complexity theory. For constant relative accuracy, Buhrman et al. (PRL 2025) recently broke the natural Grover bound $O(2^{n/2})$, where $n$ denotes the number of qubits, for both problems. In this paper, for any sufficiently small parameter $d\ge 0$, we present an even faster quantum algorithm that outputs a quantum state with energy bounded by the minimum energy over all depth-$d$ states (i.e., states obtained by applying a depth-$d$ circuit to the all-zero state), together with an estimate of this energy. For the class of Hamiltonians with depth-$d$ ground states, our…
Structural $f$-divergence: Tight universal bounds for cost function moments and gradients in parameterized quantum circuits
- Authors: Tomohiro Nishiyama, Yoshihiko Hasegawa
- arXiv: 2605.18051
- Category: new submission — Quantum Physics (quant-ph)
- Score: 5/10 (MED)
- Overlaps with: Y1 / Y3 (method: variational-circuit optimization landscape)
- Why it matters: Structural f-divergence framework giving tight universal bounds on cost-function gradients and moments in parameterized quantum circuits — addresses barren plateaus without t-design / Haar assumptions. Directly relevant to QAOA-style variational analysis in Y1 / Y3 (warm-start parameter landscape geometry).
The barren plateau phenomenon, in which cost-function gradients of variational quantum algorithms vanish exponentially, remains a central obstacle for near-term quantum computing. Existing analyses typically depend on t-design or Haar-random assumptions and bound quantities at the level of unitary distributions, offering limited insight for designing probability measures on the parameter space of parameterized quantum circuits. In this paper, we introduce the structural $f$-divergence, a symmetric $f$-divergence-based measure between probability distributions on the parameter space. We establish analytically trade-off inequalities that bound the discrepancies in the expected gradient…
The QuaST Decision Tree: Achieving Automation With Data-Based Recommendations
- Authors: Benedikt Poggel, Lena Tokuhiro, Georg Kruse, Jeanette Miriam Lorenz
- arXiv: 2605.18539
- Category: new submission — Quantum Physics (quant-ph)
- Score: 5/10 (MED)
- Overlaps with: Y1–Y4 (method: hybrid quantum-classical solver software stack)
- Why it matters: QuaST Decision Tree: software framework for end-to-end hybrid algorithm assembly (problem modelling, encoding, algorithm selection, hyperparameter tuning) with automated feasibility scoring. Same software-stack motivation as DQI-Kit (also today); complements Yuan's QAOA-portfolio pipeline.
Quantum computers are increasingly powerful. Software tools for the development of quantum-enhanced algorithms are maturing. However, the software stack still lacks the connection to applications that would enable hybrid algorithms combining classical and quantum computing steps. End users need to be assisted in choosing the best combination of preprocessing, postprocessing, classical and quantum algorithms options. The application-facing software stack is therefore required to cover problem modeling, encoding, algorithm selection and hyperparameter tuning. A variety of tools exist for specific recommendations. The QuaST Decision Tree reflects the complexity in combining individual…
Tangential (score 1–4) — 4 papers
2605.18112 · score 4/10 · Linear-optical test of quantum contextuality with sequential measurements — Linear-optical experimental KCBS contextuality test with sequential measurements. 2605.18243 · score 3/10 · One pure steered state implies Einstein-Podolsky-Rosen steering — Two-qubit entangled state with one pure steered state implies EPR steerability; characterizes Bloch-sphere-tangent steering ellipsoids. 2605.18291 · score 2/10 · Quantum randomness beyond projective measurements — Characterises intrinsic randomness from extremal POVMs beyond projective measurements. 2605.16500 · score 2/10 · Robust generalized quantum Stein's lemma — Robust generalized quantum Stein's lemma: relaxes iid assumption to almost-iid; new continuity bound for relative entropy of entanglement w.r.t. Wasserstein distance.
Summary table
| Score | arXiv ID | Short title | Overlaps | arXiv |
|---|---|---|---|---|
| 10 | 2605.17628 | A Penalty-Free Pipeline for Direct Quantum-Annealer Portfolio Optimization | Y2 (method: no-penalty), Y3 (scope: cardinality portfolio), Y4 (scope: cardinality BO) | link |
| 9 | 2605.17623 | Where the Quantum Lives in D-Wave Hybrid Portfolio Optimization | Y3 (scope: portfolio benchmark), Y4 (scope: cardinality-constrained), Y2 (method: constraint-native) | link |
| 9 | 2605.17143 | Truncated-Binary Encoding: Spectral Degree Reduction of Combinatorial Optimization Prob… | Y2 (method: encoding for QAOA), Y1 (method: warm-start basin analysis) | link |
| 8 | 2605.18393 | Quantum Model for CVRPTW | Y4 (method: Grover Adaptive Search on structured feasible space) | link |
| 7 | 2605.17145 | Scaling Quantum Optimization for Unit Commitment via Pauli Correlation Encoding | Y2 (method: qubit-efficient encoding of binary decision variables) | link |
| 6 | 2605.16955 | From Constraint to Code: DQI-Kit -- A Software Framework for Decoded Quantum Interferom… | Y2 (method: encoding transformations for constrained optimization) | link |
| 6 | 2605.16944 | Efficient Hamiltonian Engineering for Adiabatic MIS Algorithms | Y3 (scope: NISQ combinatorial optimization on hardware) | link |
| 6 | 2605.17604 | Schedule-dependent basin occupation in a programmable quantum annealer | Y3 (scope: annealing-based combinatorial optimization, noise-regime benchmarking) | link |
| 6 | 2605.18241 | An Entropy-Governed Speedup for Quantum Algorithms on Local Hamiltonians | Y4 (method: Grover-bound improvement for structured Hamiltonians) | link |
| 5 | 2605.18051 | Structural $f$-divergence: Tight universal bounds for cost function moments and gradien… | Y1 / Y3 (method: variational-circuit optimization landscape) | link |
| 5 | 2605.18539 | The QuaST Decision Tree: Achieving Automation With Data-Based Recommendations | Y1–Y4 (method: hybrid quantum-classical solver software stack) | link |
| 4 | 2605.18112 | Linear-optical test of quantum contextuality with sequential measurements | Y6 (foundations: nonclassicality test on hardware, adjacent) | link |
| 3 | 2605.18243 | One pure steered state implies Einstein-Podolsky-Rosen steering | Y6 (foundations: EPR steering, adjacent) | link |
| 2 | 2605.18291 | Quantum randomness beyond projective measurements | Y6 (foundations: measurement randomness) | link |
| 2 | 2605.16500 | Robust generalized quantum Stein's lemma | Y5 (loose: SDP / relative-entropy continuity tools) | link |