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Scalable quantum detector tomography by high-performance computing Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-10-21 Timon Schapeler, Robert Schade, Michael Lass, Christian Plessl and Tim J Bartley
At large scales, quantum systems may become advantageous over their classical counterparts at performing certain tasks. Developing tools to analyze these systems at the relevant scales, in a manner consistent with quantum mechanics, is therefore critical to benchmarking performance and characterizing their operation. While classical computational approaches cannot perform like-for-like computations
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Random Natural Gradient Quantum (IF 5.1) Pub Date : 2024-10-22 Ioannis Kolotouros, Petros Wallden
Hybrid quantum-classical algorithms appear to be the most promising approach for near-term quantum applications. An important bottleneck is the classical optimization loop, where the multiple local minima and the emergence of barren plateaux make these approaches less appealing. To improve the optimization the Quantum Natural Gradient (QNG) method [15] was introduced – a method that uses information
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Nonreciprocal nonlinear responses in moving charge density waves npj Quant. Mater. (IF 5.4) Pub Date : 2024-10-21 Ying-Ming Xie, Hiroki Isobe, Naoto Nagaosa
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A comprehensive study on a tapered Paul trap: from design to potential applications Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-10-20 Bo Deng, Moritz Göb, Max Masuhr, Johannes Roßnagel, Georg Jacob, Daqing Wang and Kilian Singer
We present a tapered Paul trap whose radio frequency electrodes are inclined to the symmetric axis of the endcap electrodes, resulting in a funnel-shaped trapping potential. With this configuration, a charged particle confined in this trap has its radial degrees of freedom coupled to that of the axial direction. The same design was successfully used to experimentally realize a single-atom heat engine
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Raman-phonon-polariton condensation in a transversely pumped cavity npj Quant. Mater. (IF 5.4) Pub Date : 2024-10-17 Alexander N. Bourzutschky, Benjamin L. Lev, Jonathan Keeling
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Modeling of planar germanium hole qubits in electric and magnetic fields npj Quantum Inform. (IF 6.6) Pub Date : 2024-10-17 Chien-An Wang, H. Ekmel Ercan, Mark F. Gyure, Giordano Scappucci, Menno Veldhorst, Maximilian Rimbach-Russ
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Quantum Locally Testable Code with Constant Soundness Quantum (IF 5.1) Pub Date : 2024-10-18 Andrew Cross, Zhiyang He, Anand Natarajan, Mario Szegedy, Guanyu Zhu
In this paper, we present two constructions of quantum locally testable codes (QLTC) with constant soundness. In the first approach, we introduce an operation called check product, and show how this operation gives rise to QLTCs of constant soundness, constant rate, and distance scaling with locality. In the second approach, we consider hypergraph product of a quantum code and a classical repetition
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Efficient Parameter Optimisation for Quantum Kernel Alignment: A Sub-sampling Approach in Variational Training Quantum (IF 5.1) Pub Date : 2024-10-18 M. Emre Sahin, Benjamin C. B. Symons, Pushpak Pati, Fayyaz Minhas, Declan Millar, Maria Gabrani, Stefano Mensa, Jan Lukas Robertus
Quantum machine learning with quantum kernels for classification problems is a growing area of research. Recently, quantum kernel alignment techniques that parameterise the kernel have been developed, allowing the kernel to be trained and therefore aligned with a specific dataset. While quantum kernel alignment is a promising technique, it has been hampered by considerable training costs because the
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Context-aware coupler reconfiguration for tunable coupler-based superconducting quantum computers Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-10-16 Leanghok Hour, Sengthai Heng, Sovanmonynuth Heng, Myeongseong Go and Youngsun Han
Crosstalk, caused by unwanted interactions from the surrounding environment, remains a fundamental challenge in existing superconducting quantum computers (SQCs). We propose a method for qubit placement, connectivity, and logical qubit allocation on tunable-coupler SQCs to eliminate unnecessary qubit connections and optimize resources while reducing crosstalk errors. Existing mitigation methods carry
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Quantum Onsager relations Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-10-16 Mankei Tsang
Using quantum information geometry, I derive quantum generalizations of the Onsager rate equations, which model the dynamics of an open system near a steady state. The generalized equations hold for a flexible definition of the forces as well as a large class of statistical divergence measures and quantum-Fisher-information metrics beyond the conventional definition of entropy production. I also derive
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Simulating adiabatic quantum computing with parameterized quantum circuits Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-10-15 Ioannis Kolotouros, Ioannis Petrongonas, Miloš Prokop and Petros Wallden
Adiabatic quantum computing is a universal model for quantum computing whose implementation using a gate-based quantum computer requires depths that are unreachable in the early fault-tolerant era. To mitigate the limitations of near-term devices, a number of hybrid approaches have been pursued in which a parameterized quantum circuit prepares and measures quantum states and a classical optimization
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Absence of electron-phonon coupling superconductivity in the bilayer phase of La3Ni2O7 under pressure npj Quant. Mater. (IF 5.4) Pub Date : 2024-10-15 Zhenfeng Ouyang, Miao Gao, Zhong-Yi Lu
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Second harmonic generation induced by gate voltage oscillation in few layer MnBi2Te4 npj Quant. Mater. (IF 5.4) Pub Date : 2024-10-14 Liangcai Xu, Zichen Lian, Yongchao Wang, Xinlei Hao, Shuai Yang, Yongqian Wang, Chang Liu, Yang Feng, Yayu Wang, Jinsong Zhang
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A hierarchy of thermal processes collapses under catalysis Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-10-14 Jeongrak Son and Nelly H Y Ng
Thermal operations (TO) are a generic description for allowed state transitions under thermodynamic restrictions. However, the quest for simpler methods to encompass all these processes remains unfulfilled. We resolve this challenge through the catalytic use of thermal baths, which are assumed to be easily accessible. We select two sets of simplified operations: elementary TO (ETO) and Markovian TO
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Mapping quantum circuits to shallow-depth measurement patterns based on graph states Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-10-14 Thierry N Kaldenbach and Matthias Heller
The paradigm of measurement-based quantum computing (MBQC) starts from a highly entangled resource state on which unitary operations are executed through adaptive measurements and corrections ensuring determinism. This is set in contrast to the more common quantum circuit model, in which unitary operations are directly implemented through quantum gates prior to final measurements. In this work, we
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Energy-dependent barren plateau in bosonic variational quantum circuits Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-10-14 Bingzhi Zhang and Quntao Zhuang
Bosonic variational quantum circuits (VQCs) are crucial for information processing in microwave cavities, trapped ions, and optical systems, widely applicable in quantum communication, sensing and error correction. The trainability of such VQCs is less understood, hindered by the lack of theoretical tools such as t-design due to the infinite dimension of the continuous-variable systems involved. We
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Robust generation of N-partite N-level singlet states by identical particle interferometry Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-10-14 Matteo Piccolini, Marcin Karczewski, Andreas Winter and Rosario Lo Franco
We propose an interferometric scheme for generating the totally antisymmetric state of N identical bosons with N internal levels (generalized singlet). This state is a resource for various problems with dramatic quantum advantage. The procedure uses a sequence of Fourier multi-ports, combined with coincidence measurements filtering the results. Successful preparation of the generalized singlet is confirmed
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Physical coherent cancellation of optical addressing crosstalk in a trapped-ion experiment Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-10-14 Jeremy Flannery, Roland Matt, Luca I Huber, Kaizhao Wang, Christopher Axline, Robin Oswald and Jonathan P Home
We present an experimental investigation of coherent crosstalk cancellation methods for light delivered to a linear ion chain cryogenic quantum register. The ions are individually addressed using focused laser beams oriented perpendicular to the crystal axis, which are created by imaging each output of a multi-core photonic-crystal fibre waveguide array onto a single ion. The measured nearest-neighbor
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Why scanning tunneling spectroscopy of Sr2RuO4 sometimes doesn’t see the superconducting gap npj Quant. Mater. (IF 5.4) Pub Date : 2024-10-13 Adrian Valadkhani, Jonas B. Profe, Andreas Kreisel, P. J. Hirschfeld, Roser Valentí
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Extending the computational reach of a superconducting qutrit processor npj Quantum Inform. (IF 6.6) Pub Date : 2024-10-14 Noah Goss, Samuele Ferracin, Akel Hashim, Arnaud Carignan-Dugas, John Mark Kreikebaum, Ravi K. Naik, David I. Santiago, Irfan Siddiqi
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Single-layer digitized-counterdiabatic quantum optimization for p-spin models Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-10-13 Huijie Guan, Fei Zhou, Francisco Albarrán-Arriagada, Xi Chen, Enrique Solano, Narendra N Hegade and He-Liang Huang
Quantum computing holds the potential for quantum advantage in optimization problems, which requires advances in quantum algorithms and hardware specifications. Adiabatic quantum optimization is conceptually a valid solution that suffers from limited hardware coherence times. In this sense, counterdiabatic quantum protocols provide a shortcut to this process, steering the system along its ground state
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Security of partially corrupted quantum repeater networks Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-10-13 Adrian Harkness, Walter O Krawec and Bing Wang
Quantum Key Distribution allows two parties to establish a secret key that is secure against computationally unbounded adversaries. To extend the distance between parties, quantum networks are vital. Typically, security in such scenarios assumes the absolute worst case: namely, an adversary has complete control over all repeaters and fiber links in a network and is able to replace them with perfect
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Purifying quantum-dot light in a coherent frequency interface Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-10-13 F Chiriano, C L Morrison, J Ho, T Jaeken and A Fedrizzi
Quantum networks typically operate in the telecom wavelengths to take advantage of low-loss transmission in optical fibres. However, bright quantum dots (QDs) emitting highly indistinguishable quantum states of light, such as InGaAs QDs, often emit photons in the near infrared thus necessitating frequency conversion (FC) to the telecom band. Furthermore, the signal quality of quantum emissions is crucial
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A modified lightweight quantum convolutional neural network for malicious code detection Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-10-13 Qibing Xiong, Yangyang Fei, Qiming Du, Bo Zhao, Shiqin Di and Zheng Shan
Quantum neural network fully utilize the respective advantages of quantum computing and classical neural network, providing a new path for the development of artificial intelligence. In this paper, we propose a modified lightweight quantum convolutional neural network (QCNN), which contains a high-scalability and parameterized quantum convolutional layer and a quantum pooling circuit with quantum bit
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Characterizing randomness in parameterized quantum circuits through expressibility and average entanglement Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-10-13 Guilherme Ilário Correr, Ivan Medina, Pedro C Azado, Alexandre Drinko and Diogo O Soares-Pinto
While scalable error correction schemes and fault tolerant quantum computing seem not to be universally accessible in the near sight, the efforts of many researchers have been directed to the exploration of the contemporary available quantum hardware. Due to these limitations, the depth and dimension of the possible quantum circuits are restricted. This motivates the study of circuits with parameterized
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Model-free distortion canceling and control of quantum devices Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-10-13 Ahmed F Fouad, Akram Youssry, Ahmed El-Rafei and Sherif Hammad
Quantum devices need precise control to achieve their full capability. In this work, we address the problem of controlling closed quantum systems, tackling two main issues. First, in practice the control signals are usually subject to unknown classical distortions that could arise from the device fabrication, material properties and/or instruments generating those signals. Second, in most cases modeling
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Quantum key distribution with unbounded pulse correlations Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-10-13 Margarida Pereira, Guillermo Currás-Lorenzo, Akihiro Mizutani, Davide Rusca, Marcos Curty and Kiyoshi Tamaki
Typical security proofs of quantum key distribution (QKD) require that the emitted signals are independent and identically distributed. In practice, however, this assumption is not met because intrinsic device flaws inevitably introduce correlations between the emitted signals. Although analyses addressing this issue have been recently proposed, they only consider a restrictive scenario in which the
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Muon spin relaxation study of spin dynamics on a Kitaev honeycomb material H3LiIr2O6 npj Quant. Mater. (IF 5.4) Pub Date : 2024-10-12 Yan-Xing Yang, Cheng-Yu Jiang, Liang-Long Huang, Zi-Hao Zhu, Chang-Sheng Chen, Qiong Wu, Zhao-Feng Ding, Cheng Tan, Kai-Wen Chen, Pabi K. Biswas, Adrian D. Hillier, You-Guo Shi, Cai Liu, Le Wang, Fei Ye, Jia-Wei Mei, Lei Shu
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Pseudo twirling mitigation of coherent errors in non-Clifford gates npj Quantum Inform. (IF 6.6) Pub Date : 2024-10-11 Jader P. Santos, Ben Bar, Raam Uzdin
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Generalised Kochen–Specker theorem for finite non-deterministic outcome assignments npj Quantum Inform. (IF 6.6) Pub Date : 2024-10-10 Ravishankar Ramanathan
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Branching States as The Emergent Structure of a Quantum Universe Quantum (IF 5.1) Pub Date : 2024-10-10 Akram Touil, Fabio Anza, Sebastian Deffner, James P. Crutchfield
Quantum Darwinism builds on decoherence theory to explain the emergence of classical behavior in a fundamentally quantum universe. Within this framework we prove two crucial insights about the emergence of classical phenomenology, centered around quantum discord as the measure of quantumness of correlations. First, we show that the so-called branching structure of the joint state of the system and
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Iteration Complexity of Variational Quantum Algorithms Quantum (IF 5.1) Pub Date : 2024-10-10 Vyacheslav Kungurtsev, Georgios Korpas, Jakub Marecek, Elton Yechao Zhu
There has been much recent interest in near-term applications of quantum computers, i.e., using quantum circuits that have short decoherence times due to hardware limitations. Variational quantum algorithms (VQA), wherein an optimization algorithm implemented on a classical computer evaluates a parametrized quantum circuit as an objective function, are a leading framework in this space. An enormous
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Implementing any Linear Combination of Unitaries on Intermediate-term Quantum Computers Quantum (IF 5.1) Pub Date : 2024-10-10 Shantanav Chakraborty
We develop three new methods to implement any Linear Combination of Unitaries (LCU), a powerful quantum algorithmic tool with diverse applications. While the standard LCU procedure requires several ancilla qubits and sophisticated multi-qubit controlled operations, our methods consume significantly fewer quantum resources. The first method ($\textit{Single-Ancilla LCU}$) estimates expectation values
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Quantum lozenge tiling and entanglement phase transition Quantum (IF 5.1) Pub Date : 2024-10-10 Zhao Zhang, Israel Klich
While volume violation of area law has been exhibited in several quantum spin chains, the construction of a corresponding ground state in higher dimensions, entangled in more than one direction, has been an open problem. Here we construct a 2D frustration-free Hamiltonian with maximal violation of the area law. We do so by building a quantum model of random surfaces with color degree of freedom that
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Decoding algorithms for surface codes Quantum (IF 5.1) Pub Date : 2024-10-10 Antonio deMarti iOlius, Patricio Fuentes, Román Orús, Pedro M. Crespo, Josu Etxezarreta Martinez
Quantum technologies have the potential to solve certain computationally hard problems with polynomial or super-polynomial speedups when compared to classical methods. Unfortunately, the unstable nature of quantum information makes it prone to errors. For this reason, quantum error correction is an invaluable tool to make quantum information reliable and enable the ultimate goal of fault-tolerant quantum
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Quantum teleportation implies symmetry-protected topological order Quantum (IF 5.1) Pub Date : 2024-10-10 Yifan Hong, David T. Stephen, Aaron J. Friedman
We constrain a broad class of teleportation protocols using insights from locality. In the "standard" teleportation protocols we consider, all outcome-dependent unitaries are Pauli operators conditioned on linear functions of the measurement outcomes. We find that all such protocols involve preparing a "resource state" exhibiting symmetry-protected topological (SPT) order with Abelian protecting symmetry
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Resource Efficient Boolean Function Solver on Quantum Computer Quantum (IF 5.1) Pub Date : 2024-10-10 Xiang Li, Hanxiang Shen, Weiguo Gao, Yingzhou Li
Nonlinear boolean equation systems play an important role in a wide range of applications. Grover's algorithm is one of the best-known quantum search algorithms in solving the nonlinear boolean equation system on quantum computers. In this paper, we propose three novel techniques to improve the efficiency under Grover's algorithm framework. A W-cycle circuit construction introduces a recursive idea
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Simultaneous measurement of multiple incompatible observables and tradeoff in multiparameter quantum estimation npj Quantum Inform. (IF 6.6) Pub Date : 2024-10-06 Hongzhen Chen, Lingna Wang, Haidong Yuan
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Signature of pressure-induced topological phase transition in ZrTe5 npj Quant. Mater. (IF 5.4) Pub Date : 2024-10-05 Zoltán Kovács-Krausz, Dániel Nagy, Albin Márffy, Bogdan Karpiak, Zoltán Tajkov, László Oroszlány, János Koltai, Péter Nemes-Incze, Saroj P. Dash, Péter Makk, Szabolcs Csonka, Endre Tóvári
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Gibbs state sampling via cluster expansions npj Quantum Inform. (IF 6.6) Pub Date : 2024-10-04 Norhan M. Eassa, Mahmoud M. Moustafa, Arnab Banerjee, Jeffrey Cohn
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Charge order near the antiferromagnetic quantum critical point in the trilayer high Tc cuprate HgBa2Ca2Cu3O8+δ npj Quant. Mater. (IF 5.4) Pub Date : 2024-10-04 V. Oliviero, I. Gilmutdinov, D. Vignolles, S. Benhabib, N. Bruyant, A. Forget, D. Colson, W. A. Atkinson, C. Proust
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Repeated measurements on non-replicable systems and their consequences for Unruh-DeWitt detectors Quantum (IF 5.1) Pub Date : 2024-10-03 Nicola Pranzini, Guillermo García-Pérez, Esko Keski-Vakkuri, Sabrina Maniscalco
The Born rule describes the probability of obtaining an outcome when measuring an observable of a quantum system. As it can only be tested by measuring many copies of the system under consideration, it does not hold for non-replicable systems. For these systems, we give a procedure to predict the future statistics of measurement outcomes through Repeated Measurements (RM). This is done by extending
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Differentiating and Integrating ZX Diagrams with Applications to Quantum Machine Learning Quantum (IF 5.1) Pub Date : 2024-10-04 Quanlong Wang, Richie Yeung, Mark Koch
ZX-calculus has proved to be a useful tool for quantum technology with a wide range of successful applications. Most of these applications are of an algebraic nature. However, other tasks that involve differentiation and integration remain unreachable with current ZX techniques. Here we elevate ZX to an analytical perspective by realising differentiation and integration entirely within the framework
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Mixed-state additivity properties of magic monotones based on quantum relative entropies for single-qubit states and beyond Quantum (IF 5.1) Pub Date : 2024-10-04 Roberto Rubboli, Ryuji Takagi, Marco Tomamichel
We prove that the stabilizer fidelity is multiplicative for the tensor product of an arbitrary number of single-qubit states. We also show that the relative entropy of magic becomes additive if all the single-qubit states but one belong to a symmetry axis of the stabilizer octahedron. We extend the latter results to include all the $\alpha$-$z$ Rényi relative entropy of magic. This allows us to identify
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Quantum-classical tradeoffs and multi-controlled quantum gate decompositions in variational algorithms Quantum (IF 5.1) Pub Date : 2024-10-04 Teague Tomesh, Nicholas Allen, Daniel Dilley, Zain Saleem
The computational capabilities of near-term quantum computers are limited by the noisy execution of gate operations and a limited number of physical qubits. Hybrid variational algorithms are well-suited to near-term quantum devices because they allow for a wide range of tradeoffs between the amount of quantum and classical resources used to solve a problem. This paper investigates tradeoffs available
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High-fidelity spin readout via the double latching mechanism npj Quantum Inform. (IF 6.6) Pub Date : 2024-10-03 Haruki Kiyama, Danny van Hien, Arne Ludwig, Andreas D. Wieck, Akira Oiwa
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Gate-set evaluation metrics for closed-loop optimal control on nitrogen-vacancy center ensembles in diamond npj Quantum Inform. (IF 6.6) Pub Date : 2024-10-02 Philipp J. Vetter, Thomas Reisser, Maximilian G. Hirsch, Tommaso Calarco, Felix Motzoi, Fedor Jelezko, Matthias M. Müller
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Quantum Multiple Eigenvalue Gaussian filtered Search: an efficient and versatile quantum phase estimation method Quantum (IF 5.1) Pub Date : 2024-10-02 Zhiyan Ding, Haoya Li, Lin Lin, HongKang Ni, Lexing Ying, Ruizhe Zhang
Quantum phase estimation is one of the most powerful quantum primitives. This work proposes a new approach for the problem of multiple eigenvalue estimation: Quantum Multiple Eigenvalue Gaussian filtered Search (QMEGS). QMEGS leverages the Hadamard test circuit structure and only requires simple classical postprocessing. QMEGS is the first algorithm to simultaneously satisfy the following two properties:
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Topological photon pumping in quantum optical systems Quantum (IF 5.1) Pub Date : 2024-10-02 Mathias B. M. Svendsen, Marcel Cech, Max Schemmer, Beatriz Olmos
We establish the concept of topological pumping in one-dimensional systems with long-range couplings and apply it to the transport of a photon in quantum optical systems. In our theoretical investigation, we introduce an extended version of the Rice-Mele model with all-to-all couplings. By analyzing its properties, we identify the general conditions for topological pumping and theoretically and numerically
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(Almost-)Quantum Bell Inequalities and Device-Independent Applications Quantum (IF 5.1) Pub Date : 2024-10-02 Yuan Liu, Ho Yiu Chung, Ravishankar Ramanathan
Investigations of the boundary of the quantum correlation set have gained increased attention in recent years. This is done through the derivation of quantum Bell inequalities, which are related to Tsirelson's problem and have significant applications in device-independent (DI) information processing. However, determining quantum Bell inequalities is a notoriously difficult task and only isolated examples
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Collapse of metallicity and high-Tc superconductivity in the high-pressure phase of FeSe0.89S0.11 npj Quant. Mater. (IF 5.4) Pub Date : 2024-09-30 Pascal Reiss, Alix McCollam, Zachary Zajicek, Amir A. Haghighirad, Amalia I. Coldea
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Interorbital antisymmetric hopping generated flat bands on kagome and pyrochlore Lattices npj Quant. Mater. (IF 5.4) Pub Date : 2024-09-30 Keyu Zeng, Ziqiang Wang
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Randomized semi-quantum matrix processing npj Quantum Inform. (IF 6.6) Pub Date : 2024-09-30 Allan Tosta, Thais de Lima Silva, Giancarlo Camilo, Leandro Aolita
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Secure and robust randomness with sequential quantum measurements npj Quantum Inform. (IF 6.6) Pub Date : 2024-09-30 Matteo Padovan, Giulio Foletto, Lorenzo Coccia, Marco Avesani, Paolo Villoresi, Giuseppe Vallone
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From architectures to applications: a review of neural quantum states Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-09-29 Hannah Lange, Anka Van de Walle, Atiye Abedinnia and Annabelle Bohrdt
Due to the exponential growth of the Hilbert space dimension with system size, the simulation of quantum many-body systems has remained a persistent challenge until today. Here, we review a relatively new class of variational states for the simulation of such systems, namely neural quantum states (NQS), which overcome the exponential scaling by compressing the state in terms of the network parameters
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Protocol for certifying entanglement in surface spin systems using a scanning tunneling microscope npj Quantum Inform. (IF 6.6) Pub Date : 2024-09-28 Rik Broekhoven, Curie Lee, Soo-hyon Phark, Sander Otte, Christoph Wolf
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OPA tomography of non-Gaussian states of light Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-09-26 Éva Rácz, László Ruppert and Radim Filip
Current advances in nonlinear optics have made it possible to perform a homodyne-like tomography of an unknown state without highly efficient detectors or a strong local oscillator. Thereby, a new experimental direction has been opened into multimode and large-bandwidth quantum optics. An optical parametric amplifier (OPA) allows us to reconstruct the quadrature distribution of an unknown state directly
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Relating Wigner’s Friend Scenarios to Nonclassical Causal Compatibility, Monogamy Relations, and Fine Tuning Quantum (IF 5.1) Pub Date : 2024-09-26 Yìlè Yīng, Marina Maciel Ansanelli, Andrea Di Biagio, Elie Wolfe, David Schmid, Eric Gama Cavalcanti
Nonclassical causal modeling was developed in order to explain violations of Bell inequalities while adhering to relativistic causal structure and $faithfulness$---that is, avoiding fine-tuned causal explanations. Recently, a no-go theorem that can be viewed as being stronger than Bell's theorem has been derived, based on extensions of the Wigner's friend thought experiment: the Local Friendliness
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Stochastic Thermodynamics at the Quantum-Classical Boundary: A Self-Consistent Framework Based on Adiabatic-Response Theory Quantum (IF 5.1) Pub Date : 2024-09-26 Joshua Eglinton, Federico Carollo, Igor Lesanovsky, Kay Brandner
Microscopic thermal machines promise to play an important role in future quantum technologies. Making such devices widely applicable will require effective strategies to channel their output into easily accessible storage systems like classical degrees of freedom. Here, we develop a self-consistent theoretical framework that makes it possible to model such quantum-classical hybrid devices in a thermodynamically
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A linear photonic swap test circuit for quantum kernel estimation Quantum Sci. Technol. (IF 5.6) Pub Date : 2024-09-26 Alessio Baldazzi, Nicolò Leone, Matteo Sanna, Stefano Azzini, Lorenzo Pavesi
The swap test is a quantum algorithm capable of computing the absolute value of the scalar product of two arbitrary wavefunctions. Scalar products represent a crucial ingredient to many quantum machine learning (QML) methods, but their evaluation is not straightforward at all. For this reason, many research efforts have been made without achieving an efficient and robust implementation. Here, we present