Quantum Materials & Devices: Hardware Components & Fabrication
Quantum materials news: quantum device fabrication, superconductors, quantum dots, 2D materials. Quantum hardware components & substrates.
Quantum materials and devices form the foundational hardware layer enabling all quantum technologies, requiring specialized materials with precise quantum properties including superconductors, topological insulators, 2D materials like graphene, and semiconductor heterostructures for qubit fabrication.
India's Quantum Materials and Devices Initiatives
India's National Quantum Mission includes Quantum Materials & Devices as the fourth thematic vertical with dedicated funding. The QMD Tech Foundation at IIT Delhi serves as the Thematic Hub on Quantum Materials and Devices, established under the T-Hub framework of NQM. The hub focuses on developing indigenous materials for quantum technologies including substrates for superconducting circuits, quantum dots for spin qubits, and specialized semiconductors.
The ₹720 crore investment for quantum fabrication facilities announced in November 2025 supports this vertical, with facilities at: IISc Bengaluru: Quantum computing fabrication for superconducting, photonic, and spin qubits (3-5 qubits per chip initially, scaling to 20-100 qubits); IIT Bombay: Quantum sensing and device fabrication; IIT Delhi: Quantum materials and packaging; IIT Kanpur: Smaller facility for specialized devices.
The Indian Institute of Technology Madras Centre for Quantum Information, Communication and Computing (CQuICC) houses India's first remotely accessible semiconductor qubit facility, capable of fabricating 3-5 qubit chips per run with 95% device yield.
Research Areas: Superconducting materials: Niobium and aluminum thin films for Josephson junctions; Semiconductor quantum dots: Silicon and III-V materials for spin qubits; 2D materials: Graphene, transition metal dichalcogenides for novel qubit designs; Topological materials: Research into materials exhibiting Majorana zero modes; Photonic materials: Silicon photonics, nonlinear optical crystals for quantum light sources.
The Defence Research and Development Organisation (DRDO) develops quantum materials for defense applications including secure communications and sensing. The Department of Atomic Energy (RRCAT, Indore) provides specialized laser and materials processing capabilities for quantum device fabrication. The NQM targets developing superconductors, novel semiconductor structures, and quantum materials for memory and device fabrication as key deliverables within the 8-year mission timeline.
quantum-computingBit flips, saturation, and quantum chaos in dissipative cat qubits
--> Quantum Physics arXiv:2605.24100 (quant-ph) [Submitted on 22 May 2026] Title:Bit flips, saturation, and quantum chaos in dissipative cat qubits Authors:Filippo Ferrari, Joachim Cohen, Vincenzo Savona, Fabrizio Minganti View a PDF of the paper titled Bit flips, saturation, and quantum chaos in dissipative cat qubits, by Filippo Ferrari and Joachim Cohen and Vincenzo Savona and Fabrizio Minganti View PDF HTML (experimental) Abstract:Bosonic cat qubits promise hardware-efficient quantum error correction because their logical bit-flip rate is exponentially suppressed with the photon number of the cat state. However, several experiments report a saturation of this suppression at large photon numbers, thus limiting the achievable protection. Combining quantum-trajectory simulations, semiclassical analysis, and Liouvillian spectral methods, we investigate the properties of bit flips in realistic dissipative cat qubits, where a memory mode hosting quantum information interacts with a dissipative buffer cavity. We show that bit flips are dynamical processes inherently involving both the memory and buffer, and therefore cannot be captured by single-mode approximate descriptions. We identify a reflection symmetry, resulting in a phase-locking condition at the semiclassical level and for quantum trajectories, as the main requirement for regular bit-flip dynamics. Its breakdown is the origin of the saturation, and we find that it occurs when two conditions are met. First, the adiabatic approximation, where the state of the buffer instantaneously follows that of the memory, must not be valid, which typically happens at large photon numbers. Second, key parameters such as the cross-Kerr interaction and dephasing must be present, leading to irregular dynamics in which memory fluctuations are amplified by the buffer during bit flips. In this regime, we find that bit flips manifest as chaotic bursts within otherwise regular dynamics, as evidenced by both changes in the topology o
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quantum-computingOptimal Quantum Differential Privacy via Fisher Information Spectral Analysis
--> Quantum Physics arXiv:2605.24166 (quant-ph) [Submitted on 22 May 2026] Title:Optimal Quantum Differential Privacy via Fisher Information Spectral Analysis Authors:Justice Owusu Agyemang, Jerry John Kponyo, Elliot Amponsah, Godfred Manu Addo Boakye View a PDF of the paper titled Optimal Quantum Differential Privacy via Fisher Information Spectral Analysis, by Justice Owusu Agyemang and 3 other authors View PDF HTML (experimental) Abstract:The Quantum Fisher Information (QFI) metric governs a fundamental duality: it quantifies both how precisely a parameter can be estimated (metrology) and how distinguishable two quantum states are (privacy). We exploit this duality to establish a geometry-aware framework for quantum differential privacy (DP) that replaces isotropic depolarizing noise with direction-dependent noise aligned to the QFI eigenstructure of the quantum embedding. We prove six principal theorems: (1) the minimax-optimal mechanism concentrates the noise budget in the dominant QFI eigenmode, achieving $\varepsilon = (\Delta^2/2)\lambda_{\max}(1-c\gamma)$ with $O(d/\lambda_{\max})$ advantage; (2) mixed-state QFI decomposition reveals that dephasing in the adversary's basis $\textit{increases}$ accessible information, while misaligned-basis dephasing provides constructive privacy amplification from hardware noise; (3) a tight privacy $-$ utility uncertainty relation $\varepsilon \cdot (1 - F) \ge \frac{\Delta^2}{2}\frac{\operatorname{Tr}(F)}{d}$; (4) adaptive QFI estimation converging at $O(1/\sqrt{n})$ yields $1.92\times$ tighter bounds; (5) QFI-aligned composition saturates at $O(1)$ versus $O(k)$ for standard composition; and (6) hardware noise can be harnessed for privacy amplification. Adversarial vulnerabilities, Wasserstein guarantees, subspace projection, and a zero-knowledge audit protocol follow as corollaries. Results are validated on Qiskit Aer GPU simulations, IBM Quantum hardware (ibm_fez, 156 qubits), and against classical DP baselines, achiev
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quantum-computingQuantum-Adaptive KS($\varphi$): A Parameterized Three-Qubit Gate Family Embedding Toffoli with Measurement-Free Phase Kickback and Intrinsic Error Non-Amplification
--> Quantum Physics arXiv:2605.24182 (quant-ph) [Submitted on 22 May 2026] Title:Quantum-Adaptive KS($φ$): A Parameterized Three-Qubit Gate Family Embedding Toffoli with Measurement-Free Phase Kickback and Intrinsic Error Non-Amplification Authors:Kripa Sankaranarayanan, Marek Perkowski View a PDF of the paper titled Quantum-Adaptive KS($\varphi$): A Parameterized Three-Qubit Gate Family Embedding Toffoli with Measurement-Free Phase Kickback and Intrinsic Error Non-Amplification, by Kripa Sankaranarayanan and 1 other authors View PDF Abstract:We introduce Quantum-Adaptive KS($\varphi$) ($K$ = kickback, $S$ = sandwich), a parameterized three-qubit gate family that structurally embeds the Toffoli (CCX) gate within two additional components: (1)a palindromic Hadamard sandwich on the first control qubit $q_0$ that conjugates $Z$-type errors to $X$-type in the CCX frame, providing simultaneous sensitivity to both error types without ancilla overhead; and (2)a controlled-phase (CP) gate whose quantum phase kickback propagates post-CCX target-state information into the control-qubit phase without measurement. The term Quantum- Adaptive refers to amplitude steering conditioned by the compile-time parameter $\varphi$ via a Quantum Neural Cellular Automaton (QNCA) majority-inspired bias rule; the gate does not self-modify at runtime. Two QA-KS($\pi$) gates chained on a shared control qubit $q_0$ produce outputs completely orthogonal to two sequential CCX gates on $q_0$=1 inputs (output fidelity F=0.000), while agreeing exactly on $q_0$=0 inputs (F=1.000). This subspace-dependent divergence is the direct computational signature of coherent phase retention across gate boundaries -- impossible for CCX-only circuits. On the $q_1$ = 0 subspace the gate acts deterministically (up to a relative phase), providing intrinsic error non-amplification. On the $q_1$ = 1 subspace it produces four-component entangled superpositions, making it a strictly distinct quantum-native primitive from
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quantum-computingDigital twins for compact hybrid quantum classical learning in FMCW radar detection
--> Quantum Physics arXiv:2605.24187 (quant-ph) [Submitted on 22 May 2026] Title:Digital twins for compact hybrid quantum classical learning in FMCW radar detection Authors:Sebastian Ratto Valderrama, Ahmed N. Sayed, Arien Sligar, Jose R. Rosas-Bustos, Omar M. Ramahi, George Shaker View a PDF of the paper titled Digital twins for compact hybrid quantum classical learning in FMCW radar detection, by Sebastian Ratto Valderrama and 5 other authors View PDF HTML (experimental) Abstract:Frequency-modulated continuous-wave radar sensing often relies on labeled measurements that are costly, restricted, or difficult to collect at scale. This work evaluates physics-informed digital twins as controlled testbeds for early-stage quantum-classical radar learning. Two synthetic radar benchmarks are considered: unmanned aerial vehicle classification from range-Doppler maps and human fall detection from Doppler-time spectrograms. For both tasks, inputs are standardized, reduced using principal component analysis, and classified using either a radial basis function support vector classifier or a quantum support vector classifier. All quantum-kernel results are obtained using noiseless classical simulation; no quantum hardware is used, and no quantum-advantage claim is made. Across five random seeds, the quantum support vector classifier improves the UAV benchmark from four principal components onward, reaching an accuracy of 0.941 +/- 0.012 at eight components, compared with 0.880 +/- 0.029 for the classical baseline. On the fall-detection benchmark, both classifiers perform similarly, with a small quantum-kernel improvement at higher feature dimensions. A Gaussian-noise robustness study shows limited performance degradation across the tested noise levels, while preserving the UAV quantum-kernel gain. These results support digital twins as useful, controlled environments for radar-QML benchmarking prior to measured-data validation and hardware execution. Comments: Subjects: Quantum
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quantum-computingHybrid Quantum-Classical Machine Learning Algorithms for Multi-Output Time-Series Forecasting at Utility Scale
--> Quantum Physics arXiv:2605.24252 (quant-ph) [Submitted on 22 May 2026] Title:Hybrid Quantum-Classical Machine Learning Algorithms for Multi-Output Time-Series Forecasting at Utility Scale Authors:Mackenson Polché, Varun Puram, Aditi Lal, Weronika Golletz, Joan Étude Arrow, Vardaan Sahgal, Kumar Ghosh, Giorgio Cortiana, Corey O'Meara View a PDF of the paper titled Hybrid Quantum-Classical Machine Learning Algorithms for Multi-Output Time-Series Forecasting at Utility Scale, by Mackenson Polch\'e and 8 other authors View PDF HTML (experimental) Abstract:Multi-output time-series forecasting in energy systems is challenging because of nonlinear dynamics, multi-scale seasonality, and strong dependencies across correlated series. In this work, we investigate two hybrid quantum-classical frameworks for multi-stream time-series forecasting on a real Smart Meter dataset comprising 103 household electricity consumption time-series, with experiments executed on the $ibm\_marrakesh$ superconducting quantum processor. The first model, Kernelized Quantum Reservoir Computing with Repeated Measurement (KQRC-RM), combines coupled quantum reservoirs, ancilla-assisted repeated measurement, and kernelized readouts to model temporal dynamics and cross-stream correlations jointly. For a 3-stream time-series input and output, the KQRC-RM model using 114 qubits achieves an MAE of 0.0811 on MPS simulator (36.92\% improvement over its classical analog) whereas performance degrades to an MAE of 0.1524 on hardware. The second, a Projected Quantum Kernel Gaussian Process (QGP), replaces fidelity-based kernels with projected kernels constructed from local reduced-state statistics. Using a topology-aware 100-qubit QGP model to predict 100 multi-output time-series values, we observe 49\% of time-series outputs achieve high-accuracy predictions (MAE $<0.15$), with an average MAE of $0.082$ for this low-error group. The medium-error regime (MAE $0.15$-$0.35$) has an average MAE of $0.229$, wh
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quantum-computingQuantum non-demolition measurements as a practical primitive for fault-tolerant computation against biased noise
--> Quantum Physics arXiv:2605.24262 (quant-ph) [Submitted on 22 May 2026] Title:Quantum non-demolition measurements as a practical primitive for fault-tolerant computation against biased noise Authors:Christophe Vuillot, Diego Ruiz, Jérémie Guillaud, Mazyar Mirrahimi View a PDF of the paper titled Quantum non-demolition measurements as a practical primitive for fault-tolerant computation against biased noise, by Christophe Vuillot and Diego Ruiz and J\'er\'emie Guillaud and Mazyar Mirrahimi View PDF Abstract:Leveraging noise bias, where phase-flip errors dominate over bit-flips, can drastically reduce the hardware overhead of fault-tolerant quantum computation, but existing approaches require bias-preserving CNOT gates whose implementation remains experimentally challenging and is provably impossible for strictly two-dimensional systems. We show that high-fidelity quantum non-demolition (QND) multi-qubit Pauli $Z$ measurements provide an equally powerful yet more accessible primitive. We demonstrate that such measurements can fully replace bias-preserving CNOT gates for compiling all operations required by bias-tailored error correction, including stabilizer measurements for repetition codes, XZZX surface codes, and LDPC codes. We propose concrete physical implementations of this primitive for two platforms: solid-state nuclear spins coupled to electron spin ancillas, and dissipatively stabilized superconducting cat qubits. Through circuit-level numerical simulations, we show that an asymmetric XZZX surface code implemented with weight-four QND $Z$ measurements achieves a phase-flip threshold of $\sim\!1.25\%$ and provides a qubit overhead reduction of up to $6\times$ compared to a bias-unaware surface code at noise bias $\eta = 10^4$. In the regime of very large bias, a repetition code with QND $Z$ measurements attains a threshold of $\sim\!2.3\%$ and achieves overhead comparable to that of a bias-preserving CNOT scheme, without requiring such a gate. Our results
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quantum-computingMultiple fidelities and joint numerical range
--> Quantum Physics arXiv:2605.24360 (quant-ph) [Submitted on 23 May 2026] Title:Multiple fidelities and joint numerical range Authors:Pei Li, Bang-Hai Wang View a PDF of the paper titled Multiple fidelities and joint numerical range, by Pei Li and Bang-Hai Wang View PDF HTML (experimental) Abstract:We investigate the effectiveness of entanglement detection based on multiple fidelities via the geometry of the joint separable numerical range. When all reference states are product states, we derive a necessary and sufficient criterion for such detection: either some pair of reference states has nontrivial moduli of the local inner products on both subsystems, or the orthogonal complement of the span of the reference states is completely entangled. We further show that there exist sets of reference product states for which no proper subset is effective for entanglement detection, whereas the full set is. A typical example of this phenomenon is provided by unextendible product bases. Moreover, for a pair of reference product states on a bipartite system with arbitrary local dimensions, we characterize both the joint numerical range and the joint separable numerical range, showing that the joint separable numerical range is determined solely by their local fidelities, as illustrated by a representative two-qubit example. Our results offer a systematic approach to designing effective entanglement witnesses and lay the groundwork for extensions to higher-dimensional and multipartite scenarios. Comments: Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2605.24360 [quant-ph] (or arXiv:2605.24360v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2605.24360 Focus to learn more arXiv-issued DOI via DataCite (pending registration) Submission history From: Bang-Hai Wang [view email] [v1] Sat, 23 May 2026 02:52:12 UTC (108 KB) Full-text links: Access Paper: View a PDF of the paper titled Multiple fidelities and joint numerical range, by Pei Li and Bang
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quantum-computingPodcast with Klea Dhimitri of Hamamtsu Photonics
Klea Dhmitri of Hamamatsu joins Yuval to discuss the company’s role as a photonic component provider for trapped-ion and neutral-atom quantum computers. She explains key technologies such as photomultiplier tubes (PMTs), SPADs, and quantitative CMOS cameras, and how scaling to larger qubit arrays changes requirements for speed, resolution, and integration. Klea also shares how customer demand is pushing product innovation, reflects on her unconventional path into quantum, and offers advice for those looking to build careers in photonics and quantum technologies. Transcript Yuval: Hello, Klea. Thank you for joining me today. Klea: Hi, Yuval. I’m glad to be here. Yuval: So who are you and what do you do? Klea: Hi, yes, happy to introduce myself. So I’m Klea Dhmitri and I work for Hamamatsu Corporation, which is the North American subsidiary of Hamamatsu Photonics. And I will be with Hamamatsu eight years in June. And what I do here is I lead our quantum computing and quantum communication project here in North America. And so what that means is I engage a lot with the community in helping, you know, folks from academia to industry find solutions of the product, help them find photonic solutions of the current products that they’re building, but also keeping in mind their next generation. And this is really where I work closely with our R&D colleagues in Japan and bringing these maybe R&D or prototype solutions and detection, modulation, and even lasers to these customers. And I also do a lot of marketing as well. So you’ll find me at trade shows, doing webinars, and really creating content that explains where Hamamatsu plays in this space. And so maybe a bit of a sort of a fun tidbit is actually this role in this project did not exist when I joined the company. So it was a bit serendipitous. So I’m happy to jump into that later in the conversation if you’d like to learn more. Yuval: What kind of components does Hamamatsu provide to qua
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quantum-computingRan a compiler-generated 3-qubit bit-flip code on Rigetti's Cepheus-1-108Q via Braket, syndrome correctly identified the injected error in 87% of shots, 94.5% logical error recovery under hardware noise
I've been building QSHL (Quantum Self-Healing Language), a small compiler that emits OpenQASM 3.0 with error-correction circuits generated from a high-level specification rather than hand-wired syndrome logic. I wanted to validate the syndrome extraction on real hardware, not just simulators. Setup: 3-qubit bit-flip repetition code Two parity syndromes: s0 = parity(q0,q1) s1 = parity(q1,q2) Syndrome extraction via ancilla qubits Deliberate X error injected on q0 Expected syndrome: "10" Execution: Rigetti Cephus-1-108Q via Amazon Braket 100 shots Observed syndrome distribution: 10 (expected): 87% 11: 5% 00: 5% 01: 3% Using post-process syndrome decoding, the logical recovery rate was 94.5%. The non-ideal outcomes are consistent with real hardware effects: readout noise gate infidelity decoherence routing/SWAP overhead across the device topology For comparison, the same circuit executed deterministically on SV1 (1000/1000 expected outcomes), so the spread here is clearly hardware-driven. Important caveats: this is post-process decoding, not active fault tolerance not closed-loop real-time correction not a logical memory lifetime experiment distance-1 repetition code only Next steps are: mid-circuit measurement + conditional feedback repeated syndrome cycles higher-distance codes cross-hardware benchmarking Happy to answer questions about the compiler or lowering pipeline. submitted by /u/DestinyInDepth [link] [comments]
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Imec builds world's first High-NA EUV-fabricated quantum dot qubit device — breakthrough could pull quantum computing onto the same manufacturing roadmap as next-gen AI processors, compressing timelines - Tom's Hardware
Imec builds world's first High-NA EUV-fabricated quantum dot qubit device — breakthrough could pull quantum computing onto the same manufacturing roadmap as next-gen AI processors, compressing timelines Tom's Hardware
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quantum-computingAI-Run Robot Lab Creates Graphene And Builds Quantum Devices
Insider Brief An autonomous quantum materials research system has taken a step toward turning AI from a digital assistant into a physical laboratory scientist by autonomously creating graphene and fabricating atomically thin transistors inside a robotic mini-lab, according to a new study from researchers at Princeton University and collaborators. The system, described in a paper […]
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quantum-computingAbsorbing Many-Body Correlations into Core-Optimized Orbitals
--> Quantum Physics arXiv:2605.22977 (quant-ph) [Submitted on 21 May 2026] Title:Absorbing Many-Body Correlations into Core-Optimized Orbitals Authors:Hao Zhang, Matthew Otten View a PDF of the paper titled Absorbing Many-Body Correlations into Core-Optimized Orbitals, by Hao Zhang and 1 other authors View PDF HTML (experimental) Abstract:The cost of simulating quantum many-body systems - on classical or quantum hardware - scales with the number of variational parameters, so progress at fixed computational budget hinges on more parameter-efficient ansätze. Configuration Interaction (CI) is widely dismissed as parameter-heavy; we show this verdict is an artifact of the orbital basis. Co-optimizing the orbital basis with a sparse CI wavefunction - a method we call Core-Optimized Orbitals (COO) - absorbs a large fraction of the dynamical correlation directly into the single-particle basis, cutting the determinant count by several orders of magnitude beyond the already compact TrimCI ansatz on which it builds. On [Fe$_4$S$_4$] (54e, 36o), a billion-determinant TrimCI+COO wavefunction reaches accuracy that would require $3\!\times\!10^{14}$ determinants in a localized basis. At matched accuracy, it is $8\times$ more compact than the largest unrestricted-DMRG benchmark ($25\times$ with PT2). Across the iron-sulfur series - from [Fe$_2$S$_2$] (30e,20o) to the P-cluster (114e,73o) - TrimCI+COO is $10$-$100\times$ more compact than SU(2)-adapted DMRG with entanglement-minimized orbitals at matched accuracy. A tunable Hubbard-on-graph model factorizes the advantage into an orbital-basis gain and an ansatz gain, the latter capturing multi-center entanglement that resists MPS localization. COO therefore changes the picture of CI efficiency: sparse CI with optimized orbitals can outperform state-of-the-art tensor networks on strongly correlated multi-center systems. Comments: Subjects: Quantum Physics (quant-ph); Strongly Correlated Electrons (cond-mat.str-el); Chemical Physics
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quantum-computingAutomatic De-Quantization of Quantum Programs Using Constant Propagation
--> Quantum Physics arXiv:2605.22980 (quant-ph) [Submitted on 21 May 2026] Title:Automatic De-Quantization of Quantum Programs Using Constant Propagation Authors:Lian Remme, Alexander Weinert, Andre Waschk, Lukas Burgholzer, Robert Wille View a PDF of the paper titled Automatic De-Quantization of Quantum Programs Using Constant Propagation, by Lian Remme and 4 other authors View PDF Abstract:Quantum computing promises to solve problems beyond the reach of classical computers, but today's quantum hardware is error-prone and much slower than classical hardware. Every quantum operation is costly, making it crucial to minimize quantum resource usage in near-term algorithms. Quantum resources should only be used when they are truly essential for quantum advantage, and not wasted on operations that can be efficiently handled by classical computation. In this work, we focus on de-quantizing quantum operations to classical computation whenever possible. The approach we propose for this is hybrid quantum-classical constant propagation, an optimization which reduces quantum operations by trading them for fast, reliable classical instructions. This is done by tracking between quantum and classical states to identify and eliminate unnecessary quantum gates and controls. We formalize a hybrid state model for quantum-classical constant propagation, implement our optimizations in the open-source MQT Core tool, and evaluate them on benchmark circuits. The obtained results show that quantum-classical constant propagation can reduce costly multi-qubit operations, making quantum programs more practical and robust for near-term devices. This opens the door to new hybrid compiler strategies that leverage the best of both quantum and classical worlds. Comments: Subjects: Quantum Physics (quant-ph); Emerging Technologies (cs.ET) Cite as: arXiv:2605.22980 [quant-ph] (or arXiv:2605.22980v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2605.22980 Focus to learn mo
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quantum-computingClassical State Preparation for Variational Quantum Algorithms via Reinforcement Learning
--> Quantum Physics arXiv:2605.23138 (quant-ph) [Submitted on 22 May 2026] Title:Classical State Preparation for Variational Quantum Algorithms via Reinforcement Learning Authors:Gino Kwun, Dhanvi Bharadwaj, Gokul Subramanian Ravi View a PDF of the paper titled Classical State Preparation for Variational Quantum Algorithms via Reinforcement Learning, by Gino Kwun and 2 other authors View PDF HTML (experimental) Abstract:Variational Quantum Algorithms (VQAs) potentially offer a pathway to practical quantum advantage, but their optimization is heavily hindered by barren plateaus and numerous local minima. While classically simulable Clifford circuits can warm-start VQAs to accelerate convergence, existing heuristic-based initialization methods struggle to scale within vast combinatorial search spaces. To overcome this bottleneck, we propose CRiSP (a Clifford Reinforcement Learning agent for State Preparation), a framework that formulates discrete prefix selection as a sequential decision-making problem. CRiSP utilizes Neural-Guided Monte Carlo Tree Search, driven by a Transformer-based policy trained via self-play, to insert learned Clifford gates before fixed parameterized rotations. This enables the construction of high-quality initial states entirely through polynomial-time classical stabilizer simulation without altering the underlying circuit architecture. By integrating a curriculum learning strategy that progressively expands the search horizon, the agent efficiently scales to deep circuits. Evaluated on QAOA benchmarks of up to $22$ qubits and $1{,}370$ parameters, CRiSP outperforms state-of-the-art Clifford initialization methods by a mean of $3.17\times$ (max $45.02\times$) in average energy accuracy and $2.44\times$ (max $16.01\times$) in best-achieved energy accuracy. Assessments on VQE tasks further demonstrate the framework's robustness and generalizability. Comments: Subjects: Quantum Physics (quant-ph); Artificial Intelligence (cs.AI); Emerging Technol
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quantum-computingAnomalous Decay of Quantum Resources: The Entanglement Sudden Death Mpemba Effect
--> Quantum Physics arXiv:2605.23197 (quant-ph) [Submitted on 22 May 2026] Title:Anomalous Decay of Quantum Resources: The Entanglement Sudden Death Mpemba Effect Authors:Zhilong Liu, Zehua Tian, Jieci Wang View a PDF of the paper titled Anomalous Decay of Quantum Resources: The Entanglement Sudden Death Mpemba Effect, by Zhilong Liu and 2 other authors View PDF HTML (experimental) Abstract:In classical thermodynamics, the Mpemba effect refers to the counterintuitive observation that hot water can freeze faster than cold water, manifesting as an anomalous crossing of dynamical trajectories. While analogues of this phenomenon have been explored in quantum radiative systems and spin-chain entanglement asymmetry, its connection to the finite-time decoupling of quantum correlations remains elusive. In this Letter, we uncover a distinct quantum Mpemba effect associated with entanglement sudden death (ESD). By analyzing two qubits interacting with local amplitude damping reservoirs, we demonstrate that a more strongly entangled initial state can experience a faster collapse into a separable state than a more weakly entangled one. We provide an exact analytical derivation of the trajectory crossover dynamics and the ESD time. Finally, we map the phase diagram of initial state parameters to delineate the regime where this anomalous entanglement Mpemba effect occurs, offering insights into the control of quantum resource lifetimes in dissipative environments. Comments: Subjects: Quantum Physics (quant-ph); General Relativity and Quantum Cosmology (gr-qc) Cite as: arXiv:2605.23197 [quant-ph] (or arXiv:2605.23197v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2605.23197 Focus to learn more arXiv-issued DOI via DataCite (pending registration) Submission history From: Jieci Wang [view email] [v1] Fri, 22 May 2026 03:28:53 UTC (364 KB) Full-text links: Access Paper: View a PDF of the paper titled Anomalous Decay of Quantum Resources: The Entanglement
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quantum-computingTransition-state lattice modes and the breakdown of adiabatic tunneling for hydrogen and deuterium in bcc Nb
--> Quantum Physics arXiv:2605.23212 (quant-ph) [Submitted on 22 May 2026] Title:Transition-state lattice modes and the breakdown of adiabatic tunneling for hydrogen and deuterium in bcc Nb Authors:P. Graham Pritchard, James M. Rondinelli View a PDF of the paper titled Transition-state lattice modes and the breakdown of adiabatic tunneling for hydrogen and deuterium in bcc Nb, by P. Graham Pritchard and James M. Rondinelli View PDF HTML (experimental) Abstract:Interstitial hydrogen and deuterium in body-centered-cubic metals constitute archetypal quantum tunneling systems. Their relevance has been renewed by the connection between hydrogenic tunneling in Nb and defect-induced decoherence in superconducting qubits, motivating a predictive microscopic theory. Existing theoretical treatments invoke an adiabatic separation between the light interstitial and the host lattice, an assumption whose validity has not been rigorously established for hydrogenic species. Here, we show that the experimentally measured tunnel splittings of O-trapped H and D in bcc Nb are quantitatively reproduced only within a five-dimensional (5D) Lattice-Renormalized Born-Oppenheimer (LRBO) framework. This approach treats three interstitial modes and two judiciously selected lattice modes, which includes a transition-state mode, on equal quantum footing. By recasting nested Born-Oppenheimer hierarchies within this same formalism and benchmarking against modern \textit{ab initio} potential energy surfaces, we show that adiabatic separation of the light particle from lattice dynamics is satisfied only in the positive-muon ($\mu^{+}$) mass limit. In contrast, tunneling for H and D is fundamentally a collective, nonadiabatic process mediated by anharmonic lattice couplings. Finally, we show that the breakdown of adiabaticity can be anticipated from simple energy estimates involving the ground-state light-particle energy evaluated at a small number of fixed lattice configurations, providing a practic
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quantum-computingInterference of local-measurement histories
--> Quantum Physics arXiv:2605.23232 (quant-ph) [Submitted on 22 May 2026] Title:Interference of local-measurement histories Authors:Parveen Kumar, Igor V. Gornyi, Yuval Gefen View a PDF of the paper titled Interference of local-measurement histories, by Parveen Kumar and 2 other authors View PDF HTML (experimental) Abstract:The evolution of a quantum system comprises two fundamental processes--continuous unitary dynamics and stochastic measurement-induced jumps. The latter are often viewed as a source of decoherence. Can two histories of such an evolution, made up of local measurements, interfere with each other? Here, we answer this question in the affirmative. A manifestation of this interference is the generation of entanglement between two parts of the system that are individually coupled to distinct detectors. Specifically, we develop a protocol in which two alternative local measurement processes act on a pair of qubits, and show how interference of histories is generated under coherent control, leading to entanglement. Furthermore, we find that averaging over the detectors' readouts still results in an entangled (albeit not maximally entangled) state. Our results extend the notion of quantum interference beyond unitary evolution to genuinely measurement-driven dynamics, and identify limits on the generation of quantum correlations using interference of measurement histories. Comments: Subjects: Quantum Physics (quant-ph); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Strongly Correlated Electrons (cond-mat.str-el) Cite as: arXiv:2605.23232 [quant-ph] (or arXiv:2605.23232v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2605.23232 Focus to learn more arXiv-issued DOI via DataCite (pending registration) Submission history From: Parveen Kumar [view email] [v1] Fri, 22 May 2026 04:49:04 UTC (520 KB) Full-text links: Access Paper: View a PDF of the paper titled Interference of local-measurement histories, by Parveen Kumar and 2 o
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quantum-computingLocal-Observable-Guided Generative Quantum Circuits for Degenerate Ground Spaces
--> Quantum Physics arXiv:2605.23300 (quant-ph) [Submitted on 22 May 2026] Title:Local-Observable-Guided Generative Quantum Circuits for Degenerate Ground Spaces Authors:Yiying Chen, Lingxia Zhang, Yanzheng Zhu, Kaiyan Yang, Xiao Zeng, Zizhu Wang View a PDF of the paper titled Local-Observable-Guided Generative Quantum Circuits for Degenerate Ground Spaces, by Yiying Chen and 4 other authors View PDF HTML (experimental) Abstract:Searching for degenerate ground spaces in quantum many-body systems is central to understanding spontaneous symmetry breaking and topological order. Although existing numerical methods can approximate individual ground states with high accuracy, recovering the full degenerate space remains a substantial challenge. Here we tackle this problem using a hybrid generative quantum circuit that combines a classical generative model with an expressive parameterized quantum circuit (PQC). The classical model learns a distribution over PQC parameters, enabling the sampling of an ensemble of ground states, while the PQC ensures compatibility with quantum hardware. To promote both low energy and state diversity, we define an energy-diversity objective composed of an energy-minimization term and cosine-similarity penalties derived from local observable correlators. These local descriptors provide a scalable, measurement-efficient means of distinguishing distinct ground states. We benchmark the framework on the Majumdar-Ghosh model, the Affleck-Kennedy-Lieb-Tasaki model, and the spin-1 XXZ chain, which realize distinct mechanisms of degeneracy. In all cases, the method produces a diverse ensemble whose linear span accurately reproduces the target ground space, in some instances, it identifies an approximately orthogonal basis within the learned ensemble. We further show that the framework remains robust under shot-based estimation and can still recover the degenerate ground space with a reduced measurement budget. Comments: Subjects: Quantum Physics (quan
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quantum-computingUAE Advances One of the World’s First National Post-Quantum Migration Programs
The UAE Cyber Security Council has partnered with QuantumGate to launch the national Crypto Discovery Tool. This Abu Dhabi-built solution provides comprehensive cryptographic discovery and inventory management to support the country's post-quantum migration. It equips organizations with end-to-end visibility across complex infrastructures, enabling a structured and secure transition to quantum-resilient encryption standards. The post UAE Advances One of the World’s First National Post-Quantum Migration Programs appeared first on The Qubit Report.
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quantum-computing2 Quantum Computing Stocks That Are Further Along Than Anyone Is Giving Them Credit For
Quantum computing promises to be one of the next big things in technology, and that's prompted many growth investors to pile into the industry. But when we think "next big thing," that doesn't necessarily mean tomorrow or even a year or two from now. One thing that's held some investors back from getting in on this high-potential technology is the idea that its usefulness may be many years or even decades away. Even experts haven't always been certain about when this exciting technology might become part of our daily lives. Early last year, Nvidia chief Jensen Huang said quantum computing was decades away from the point of being very useful. A few months later, Huang said otherwise and even announced the creation of a quantum computing research center. And Microsoft (MSFT 0.06%) co-founder Bill Gates said last year that the technology might be ready to solve big problems in three to five years. The reason it's taking a while for quantum computing to become very useful is due to the complexity of the technology. It involves using qubits for calculations rather than the bits used by classical computers -- and qubits are fragile and often difficult to scale up. But there's reason to be optimistic about the progress of certain companies. In fact, two quantum stocks are further along than anyone is giving them credit for. Let's check them out. Image source: Getty Images. 1. Microsoft You probably know Microsoft well for its software suite, including popular products like Word and Excel, and you might even be familiar with the company's cloud computing business. These are major engines, driving years of revenue and profit growth -- and this has translated into returns for investors, too, with the stock rising 700% over the past decade. ExpandNASDAQ: MSFTMicrosoftToday's Change(-0.06%) $-0.24Current Price$418.85Key Data PointsMarket Cap$3.1TDay's Range$416.35 - $424.4052wk Range$356.28 - $555.45Volume1.3MAvg Vol34.1MGross Margin68.31%Dividend Yield0.85% But, while Microsof
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