Quantum Spectral Clustering Framework via Compact Circuit Structures
KAIST（韩国科学技术院）；Qunova Computing, Inc.（Qunova计算公司）
Hyeong-Gyu Kim, Siheon Park, June-Koo Kevin Rhee
备注：
39 pages, 12 figures
发表信息：
H. Kim, S. Park, and J.-K. K. Rhee, "Quantum Spectral Clustering Framework via Compact Circuit Structures." Advanced Quantum Technologies 9, no. 10 (2026): e70456
Spectral machine learning methods based on spectral graph theory are powerful but scale poorly due to costly eigen-analysis. Although various eigenvector approximation methods have been proposed, the construction of a partial kernel matrix still remains within their frameworks. This work presents compact quantum circuit designs for spectral clustering in which the eigenproblem is approximated via a Rayleigh-Ritz formulation that bypasses kernel matrix construction and whose overall depth is dominated by the data-embedding routine. A rigorous shot complexity analysis is provided, showing that the sampling-based estimation remains tractable for the spectral clustering objective including a penalty term. Simulations on canonical datasets demonstrate reliable optimization behavior with an under-parameterized hardware-efficient ansatz. Finite-shot simulations further confirm the predicted sampling behavior of the penalty estimator, validating the main claims as a proof of concept.
In this paper we address the problem of translating one-way quantum computation (1WQC) into the circuit model. We start by giving a straightforward circuit representation of any 1WQC, at the cost of introducing many ancilla wires. We then propose a set of four simple circuit identities that explore the relationship between the entanglement resource and correction structure of a 1WQC, allowing one to obtain equivalent circuits acting on fewer qubits. We conclude with some examples and a discussion of open problems.
Quantum circuits are time dependent diagrams describing the process of quantum computation. Usually, a quantum algorithm must be mapped into a quantum circuit. Optimal synthesis of quantum circuits is intractable and heuristic methods must be employed. With the use of heuristics, the optimality of circuits is no longer guaranteed. In this paper, we consider a local optimization technique based on templates to simplify and reduce the depth of non-optimal quantum circuits. We present and analyze templates in the general case, and provide particular details for the circuits composed of NOT, CNOT …
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A Compact Broadband Purcell Filter for Superconducting Quantum Circuits in a 3D Flip-Chip Architecture
Technical University of Munich（慕尼黑工业大学）；Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften（瓦尔特·迈斯纳研究所，巴伐利亚科学院）；Fraunhofer EMFT Institute for Electronic Microsystems and Solid State Technologies（弗劳恩霍夫电子微系统和固态技术研究所）
Compact U(1) Lattice Gauge Theory in Superconducting Circuits with Infinite-Dimensional Local Hilbert Spaces
University of the Basque Country UPV/EHU（巴斯克大学）；BCMaterials, Basque Center for Materials, Applications and Nanostructures（BCMaterials，巴斯克材料、应用与纳米结构中心）；DIPC - Donostia International Physics Center（圣塞巴斯蒂安国际物理中心）；IKERBASQUE, Basque Foundation for Science（IKERBASQUE，巴斯克科学基金会）；European Organization for Nuclear Research (CERN)（欧洲核子研究组织（CERN））；Institute for Quantum Computing（量子计算研究所）；Department of Electrical & Computer Engineering, University of Waterloo（滑铁卢大学电气与计算机工程系）
For quantum computer circuits, it is proposed that they have, besides the presently used compact graphs, an expanded system of subgraphs, in line with the quantum mechanics superposition axiom. The representation of each process by these suggested graphs is equivalent to the algebraic notation of the process.
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Centro de Física de Materiales, UPV-EHU/CSIC（材料物理中心）；Donostia International Physics Center（多尼亚斯蒂国际物理中心）；Ikerbasque Foundation for Science（伊卡巴斯克科学基金会）；Multiverse Computing
Electrically-programmable frequency comb for compact quantum photonic circuits
Institute of Nuclear Sciences, Hacettepe University（哈杰泰普大学核科学研究所）；Department of Physics, Quaid-i-Azam University（奎德-阿扎姆大学物理系）；Department of Physics, Recep Tayyip Erdogan University（雷杰普·塔伊普·埃尔多安大学物理系）；Department of Nanoscience and Nanotechnology, Faculty of Arts and Science, Burdur Mehmet Akif Ersoy University（布尔杜尔·梅赫梅特·阿克夫·埃尔索伊大学文理学院纳米科学与纳米技术系）
In the strive for scalable quantum processors, significant effort is being devoted to the development of cryogenic classical hardware for the control and readout of a growing number of qubits. Here we report on a cryogenic circuit incorporating a CMOS-based active inductor enabling fast impedance measurements with a sensitivity of 10 aF and an input-referred noise of 3.7 aF/sqrt(Hz). This type of circuit is especially conceived for the readout of semiconductor spin qubits. As opposed to commonly used schemes based on dispersive rf reflectometry, which require mm-scale passive inductors, it all…
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We present a new scheme for quantum homomorphic encryption which is compact and allows for efficient evaluation of arbitrary polynomial-sized quantum circuits. Building on the framework of Broadbent and Jeffery and recent results in the area of instantaneous non-local quantum computation, we show how to construct quantum gadgets that allow perfect correction of the errors which occur during the homomorphic evaluation of T gates on encrypted quantum data. Our scheme can be based on any classical (leveled) fully homomorphic encryption (FHE) scheme and requires no computational assumptions beside…
Current quantum computer designs will not scale. To scale beyond small prototypes, quantum architectures will likely adopt a modular approach with clusters of tightly connected quantum bits and sparser connections between clusters. We exploit this clustering and the statically-known control flow of quantum programs to create tractable partitioning heuristics which map quantum circuits to modular physical machines one time slice at a time. Specifically, we create optimized mappings for each time slice, accounting for the cost to move data from the previous time slice and using a tunable lookahe…
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Implementation of variational Quantum Machine Learning (QML) algorithms on Noisy Intermediate-Scale Quantum (NISQ) devices is known to have issues related to the high number of qubits needed and the noise associated with multi-qubit gates. In this paper, we propose a variational QML algorithm using a dressed quantum network to address these issues. Using the "super compressed encoding" scheme that we follow here, the classical encoding layer in our dressed network drastically scales down the input-dimension, before feeding the input to the variational quantum circuit. Hence, the number of qubi…
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We report a compact, scalable, quantum photonic integrated circuit realised by combining multiple, independent InGaAs/GaAs quantum-light-emitting-diodes (QLEDs) with a silicon oxynitride waveguide circuit. Each waveguide joining the circuit can then be excited by a separate, independently electrically contacted QLED. We show that the emission from neighbouring QLEDs can be independently tuned to degeneracy using the Stark Effect and that the resulting photon streams are indistinguishable. This enables on-chip Hong-Ou-Mandel-type interference, as required for many photonic quantum information p…
