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| Open AccessMomentum-dependent scaling exponents of nodal self-energies measured in strange metal cuprates and modelled using semi-holography
Strange metal behaviour of high-Tc superconductors, characterised by unconventional electrical and thermodynamic properties, still poses challenges for theory. Smit et al. report experimental features in the self-energy of a strange metal that are consistent with predictions by holographic theoretical methods.
- S. Smit
- , E. Mauri
- & M. S. Golden
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Article
| Open AccessProgrammable quantum emitter formation in silicon
Quantum emitters in Si show promise for applications in quantum information processing and communication due to their potential as spin-photon interfaces. Jhuria et al. report the formation of selected telecom emitters in Si using local writing and erasing by fs laser pulses and annealing in a hydrogen atmosphere.
- K. Jhuria
- , V. Ivanov
- & T. Schenkel
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Article
| Open AccessSelf acceleration from spectral geometry in dissipative quantum-walk dynamics
The strong connection between the dynamics of a physical system and its Hamiltonian’s spectrum has scarcely been applied in the non-Hermitian case. Here, the authors use a photonic quantum walk to confirm and expand previous theoretical analyses connecting self-acceleration dynamics with non-trivial point-gap topology.
- Peng Xue
- , Quan Lin
- & Wei Yi
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Article
| Open AccessStrong microwave squeezing above 1 Tesla and 1 Kelvin
At the quantum limit, vacuum fluctuations determine the precision with which a signal can be measured. In this work the authors use a technique known as squeezing to greatly reduce the vacuum fluctuation noise present at microwave frequencies.
- Arjen Vaartjes
- , Anders Kringhøj
- & Jarryd J. Pla
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Article
| Open AccessEfficient multimode Wigner tomography
Standard ways of characterising quantum states incur exponential overhead. Here, the authors consider the task of reconstructing density matrices of multimode continuous variable systems, and demonstrate a method which scales polynomially with the system size, provided the state lies in a polynomial dimensional subspace.
- Kevin He
- , Ming Yuan
- & David I. Schuster
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Article
| Open AccessSqueezed light from an oscillator measured at the rate of oscillation
The authors demonstrated an unprecedented level of polarization squeezing of light generated by an atomic ensemble, and a new regime of continuous quantum measurements on a macroscopic material oscillator.
- Christian Bærentsen
- , Sergey A. Fedorov
- & Eugene S. Polzik
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Article
| Open AccessDeterministic positioning and alignment of a single-molecule exciton in plasmonic nanodimer for strong coupling
Realising single molecule strong coupling with plasmons achieving both deterministic molecule positioning and dipole alignment with the mode field has proven challenging so far. Here, the authors fill this gap by placing a single molecular emitter in the gap centre of an Au nanodimer system.
- Renming Liu
- , Ming Geng
- & Lin Wu
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Article
| Open AccessCoherent electric field control of orbital state of a neutral nitrogen-vacancy center
Color centers in diamond have been proposed as a link between remote superconducting units in hybrid quantum systems, where their orbital degree of freedom is utilized. Here the authors report coherent electric-field control of the orbital state of a neutral NV center in diamond.
- Hodaka Kurokawa
- , Keidai Wakamatsu
- & Hideo Kosaka
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Article
| Open AccessCavity-enhanced photon indistinguishability at room temperature and telecom wavelengths
Carbon nanotube-based single photon emitters allow for room-temperature operation, but suffer from vanishing indistinguishability due to strong dephasing. Following a theoretical proposal, the authors tackle the problem experimentally by using a cavity to enhance the photon coherence time and the emission spectral density in the regime of incoherent good cavity-coupling.
- Lukas Husel
- , Julian Trapp
- & Alexander Högele
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Article
| Open AccessMechanically induced correlated errors on superconducting qubits with relaxation times exceeding 0.4 ms
Significant efforts have been dedicated to understanding the mechanisms of decoherence in superconducting qubits. Here, using time-resolved error measurements, the authors link errors present in transmon qubits based on Nb electrodes to mechanical vibrations of a commonly used pulse tube cooler.
- Shingo Kono
- , Jiahe Pan
- & Tobias J. Kippenberg
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Article
| Open AccessEfficient characterizations of multiphoton states with an ultra-thin optical device
Shadow tomography is efficient for quantum state characterization. Here, the authors implement shadow tomography on photonic states with a single metasurface, which alleviates the complexity in measurement
- Kui An
- , Zilei Liu
- & He Lu
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Article
| Open AccessA linear response framework for quantum simulation of bosonic and fermionic correlation functions
As quantum simulations advance, the ability to measure response functions of simulated systems becomes increasingly important. Here the authors present a linear response framework for computing fermionic and bosonic response functions on a quantum computer, demonstrating advantages over existing methods.
- Efekan Kökcü
- , Heba A. Labib
- & A. F. Kemper
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Article
| Open AccessTransition role of entangled data in quantum machine learning
Given that entangled states can store more information than unentangled ones, it would be natural to assume that highly-entangled data would always enhance capabilities of quantum machine learning models. Here, the authors show that this is not the case, in particular when the allowed number of measurements to incoherently learn quantum dynamics is low
- Xinbiao Wang
- , Yuxuan Du
- & Dacheng Tao
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Article
| Open AccessMulti-site integrated optical addressing of trapped ions
A promising strategy for scaling trapped-ion-based quantum technologies is to use fully integrated optical waveguides to deliver light to numerous ions at multiple sites. Here, the authors. optically address three ions using on-chip waveguides to deliver three distinct wavelengths per ion, and perform Rabi flopping on each ion simultaneously.
- Joonhyuk Kwon
- , William J. Setzer
- & Hayden J. McGuinness
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Article
| Open AccessSurpassing millisecond coherence in on chip superconducting quantum memories by optimizing materials and circuit design
Understanding loss mechanisms in superconducting circuits is crucial for improving qubit coherence. Here the authors use a multimode resonator to study loss mechanisms in thin-film superconducting circuits and demonstrate on-chip quantum memories with lifetimes exceeding 1ms, using Ta thin-films and high-temperature substrate annealing
- Suhas Ganjam
- , Yanhao Wang
- & Robert J. Schoelkopf
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Article
| Open AccessCurrent-sensitive Hall effect in a chiral-orbital-current state
In most materials, the hall conductivity has a scaling to the longitudinal resistance that varies between linear and quadratic. Here, Zhang et al demonstrate a hall conductivity proportional to the fifth power of the longitudinal conductivity in Mn3Si2Te6, which they attribute to enhanced force on charge carriers due to chiral orbital currents.
- Yu Zhang
- , Yifei Ni
- & Gang Cao
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Article
| Open AccessSuppressing dipolar relaxation in thin layers of dysprosium atoms
Confining atoms to lattices can modify their interaction and collision. Here the authors show suppression of dipolar relaxation in the form of reduced decay rate of dysprosium atoms in quasi-2D regime.
- Pierre Barral
- , Michael Cantara
- & Wolfgang Ketterle
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Article
| Open AccessA substitutional quantum defect in WS2 discovered by high-throughput computational screening and fabricated by site-selective STM manipulation
Point defects in 2D semiconductors have potential for quantum computing applications, but their controlled design and synthesis remains challenging. Here, the authors identify and fabricate a promising quantum defect in 2D WS2 via high-throughput computational screening and scanning tunnelling microscopy.
- John C. Thomas
- , Wei Chen
- & Geoffroy Hautier
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Article
| Open AccessQuantum annealing of a frustrated magnet
Quantum annealing is usually discussed as a means of finding an optimal solution for a problem where there are many local minima, such as the travelling salesman. Here, Zhao et al present an intriguing example of quantum annealing in the case of the frustrated magnet α-CoV2O6, where a transverse magnetic field triggers the quantum annealing process.
- Yuqian Zhao
- , Zhaohua Ma
- & Yuesheng Li
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Article
| Open AccessCorrelation between two distant quasiparticles in separate superconducting islands mediated by a single spin
The authors experimentally study a chain of superconducting islands (SI) and quantum dots (QD), where a Bogoliubov quasiparticle occupies each SI. They demonstrate correlations between the quasiparticles in each SI mediated by a single spin on the QD, known as an “over-screened" doublet state of the QD.
- Juan Carlos Estrada Saldaña
- , Alexandros Vekris
- & Jesper Nygård
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Article
| Open AccessMeasuring statistics-induced entanglement entropy with a Hong–Ou–Mandel interferometer
Measuring quantum entanglement remains a demanding task. The authors introduce two functions to quantify entanglement induced by fermionic or bosonic statistics, in transport experiments. Both functions, in theory and experiment, are remarkably resilient against the nonuniversal effects of interactions.
- Gu Zhang
- , Changki Hong
- & Yuval Gefen
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Article
| Open AccessLong-baseline quantum sensor network as dark matter haloscope
Nearly a century after dark matter was proposed, yet its nature remains elusive. Here, authors present their dark photon dark matter search results using two atomic magnetometer arrays 1700 km apart in large magnetic shields and offer the strongest terrestrial constraint in this mass range to date.
- Min Jiang
- , Taizhou Hong
- & Jiangfeng Du
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Article
| Open AccessReversibility of quantum resources through probabilistic protocols
The problem of reversibility within general quantum resource theories is still an open one. Here, the authors prove that a reversible entanglement manipulation framework (and, consequently, the concept of entanglement entropy) can be formally established by adjusting the setting to allow for probabilistic operations
- Bartosz Regula
- & Ludovico Lami
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Comment
| Open AccessThe promises and challenges of many-body quantum technologies: A focus on quantum engines
Can many-body systems be beneficial to designing quantum technologies? We address this question by examining quantum engines, where recent studies indicate potential benefits through the harnessing of many-body effects, such as divergences close to phase transitions. However, open questions remain regarding their real-world applications.
- Victor Mukherjee
- & Uma Divakaran
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Article
| Open AccessNonlocality activation in a photonic quantum network
Entangled local states can be made capable of violating Bell inequalities via nonlocality activation. Typical theoretical approaches require processing many copies of the original state and performing joint measurements on the ensemble. Here, instead, the authors experimentally demonstrate how to do so using a single copy of the state, broadcasting it to two spatially separated parties within a three-node network.
- Luis Villegas-Aguilar
- , Emanuele Polino
- & Geoff J. Pryde
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Matters Arising
| Open AccessReply to: Quantum mechanical rules for observed observers and the consistency of quantum theory
- Lídia del Rio
- & Renato Renner
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Matters Arising
| Open AccessQuantum mechanical rules for observed observers and the consistency of quantum theory
- Alexios P. Polychronakos
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Article
| Open AccessQuantum simulation of the bosonic Kitaev chain
Interesting non-Hermitian quantum dynamics can be accessed in analogue quantum simulators consisting of Hermitian bosonic systems with squeezing and antisqueezing terms. Here, the authors use a coplanar waveguide resonator connected to a SQUID to simulate the bosonic version of the Kitaev chain.
- Jamal H. Busnaina
- , Zheng Shi
- & Christopher M. Wilson
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Article
| Open AccessFast joint parity measurement via collective interactions induced by stimulated emission
Parity detection is essential in quantum error correction. Here, authors propose a reliable joint parity measurement (JPM) scheme inspired by stimulated emission and experimentally implement the weight-2(4) JPM scheme in a tunable coupling superconducting circuit, which shows comparable performance to the standard CNOT-gate based scheme.
- Sainan Huai
- , Kunliang Bu
- & Yicong Zheng
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Article
| Open AccessEnhancing combinatorial optimization with classical and quantum generative models
Solving combinatorial optimization problems using quantum or quantum-inspired machine learning models would benefit from strategies able to work with arbitrary objective functions. Here, the authors use the power of generative models to realise such a black-box solver, and show promising performances on some portfolio optimization examples.
- Javier Alcazar
- , Mohammad Ghazi Vakili
- & Alejandro Perdomo-Ortiz
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Article
| Open AccessStrongly interacting Rydberg atoms in synthetic dimensions with a magnetic flux
Weak and non-interacting systems have been previously explored in synthetic dimensions. Here the authors demonstrate strong atomic interaction in synthetic dimensions using an array of Rydberg atoms.
- Tao Chen
- , Chenxi Huang
- & Bryce Gadway
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Article
| Open AccessDemonstration of hypergraph-state quantum information processing
Usual multiqubit entangled states can be described using the graph formalism, where each edge connects only two qubits. Here, instead, the authors use a reprogrammable silicon photonics chip to showcase preparation, verification and processing of arbitrary four-qubit hypergraph states, where hyperedges describe entanglement within a subset of many qubits.
- Jieshan Huang
- , Xudong Li
- & Jianwei Wang
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Article
| Open AccessEffective light cone and digital quantum simulation of interacting bosons
Studying bounds on the speed of information propagation across interacting boson systems is notoriously difficult. Here, the authors find tight bounds for both the transport of boson particles and information propagation, for arbitrary time-dependent Bose-Hubbard-type Hamiltonians in arbitrary dimensions.
- Tomotaka Kuwahara
- , Tan Van Vu
- & Keiji Saito
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Article
| Open AccessUniversal control of a bosonic mode via drive-activated native cubic interactions
Manipulating quantum information encoded in a bosonic mode requires sizeable and controllable nonlinearities, but superconducting devices’ strong nonlinearities are normally static. Here, the authors use a SNAIL to suppress static nonlinearities and use drive-dependent ones to reach universal control of a bosonic mode.
- Axel M. Eriksson
- , Théo Sépulcre
- & Simone Gasparinetti
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Article
| Open AccessOptimizing quantum gates towards the scale of logical qubits
Ensuring high-fidelity quantum gates while increasing the number of qubits poses a great challenge. Here the authors present a scalable strategy for optimizing frequency trajectories as a form of error mitigation on a 68-qubit superconducting quantum processor, demonstrating high single- and two-qubit gate fidelities.
- Paul V. Klimov
- , Andreas Bengtsson
- & Hartmut Neven
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Article
| Open AccessHermitian and non-Hermitian topology from photon-mediated interactions
Topological properties of a photonic environment are crucial to engineer robust photon-mediated interactions between quantum emitters. Here, the authors find general theorems on the topology of photon-mediated interactions, unveiling the phenomena of topological preservation and reversal.
- Federico Roccati
- , Miguel Bello
- & Angelo Carollo
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Article
| Open AccessCavity-coupled telecom atomic source in silicon
T centers in silicon are promising candidates for quantum applications yet suffer from weak optical transitions. Here, by integrating with a silicon nanocavity, the authors demonstrate an enhancement of the photon emission rate for a single T center.
- Adam Johnston
- , Ulises Felix-Rendon
- & Songtao Chen
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Article
| Open AccessExcitonic Mott insulator in a Bose-Fermi-Hubbard system of moiré WS2/WSe2 heterobilayer
Strongly interacting interlayer excitons and the interplay between excitons and electronic states have recently been studied in moire superlattices. Here the authors study moire WS2/WSe2 heterobilayer with tuneable electron and exciton populations and find signatures of an excitonic Mott insulating state.
- Beini Gao
- , Daniel G. Suárez-Forero
- & Mohammad Hafezi
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Article
| Open AccessUnderstanding quantum machine learning also requires rethinking generalization
Understanding machine learning models’ ability to extrapolate from training data to unseen data - known as generalisation - has recently undergone a paradigm shift, while a similar understanding for their quantum counterparts is still missing. Here, the authors show that uniform generalization bounds pessimistically estimate the performance of quantum machine learning models.
- Elies Gil-Fuster
- , Jens Eisert
- & Carlos Bravo-Prieto
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Article
| Open AccessRoom-temperature strong coupling in a single-photon emitter-metasurface system
Interfacing single-photon emitters (SPEs) with high-finesse cavities can prevent decoherence processes, especially at elevated temperature, but its implementation remains challenging. Here, the authors report room-temperature strong coupling of SPEs in hexagonal boron nitride with a dielectric cavity based on bound states in the continuum, showing a Rabi splitting of ~ 4 meV.
- T. Thu Ha Do
- , Milad Nonahal
- & Son Tung Ha
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Perspective
| Open AccessQuantum many-body simulations on digital quantum computers: State-of-the-art and future challenges
Digital quantum simulations of quantum many-body systems have emerged as one of the most promising applications of near-term quantum computing. This Perspective article provides an overview and an outlook on future developments in this field.
- Benedikt Fauseweh
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Article
| Open AccessMapping a 50-spin-qubit network through correlated sensing
The ability to characterize large and complex nuclear-spin networks could enable quantum applications, such as quantum simulations of many-body physics. Here the authors develop a high-resolution quantum-sensing method and use it to image a network of 50 nuclear spins surrounding a single NV center in diamond.
- G. L. van de Stolpe
- , D. P. Kwiatkowski
- & T. H. Taminiau
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Article
| Open AccessMesoscopic fluctuations in entanglement dynamics
Studying out-of-equilibrium entanglement fluctuations is beyond the scope of current theories. Lim et al. present an analytical theory of fluctuations in long-time dynamics of entanglement in two classes of integrable lattice models, showing features reminiscent of universal mesoscopic fluctuations.
- Lih-King Lim
- , Cunzhong Lou
- & Chushun Tian
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Article
| Open AccessTransfer learning with graph neural networks for improved molecular property prediction in the multi-fidelity setting
Modern molecular discovery processes generate millions of measurements at different quality levels. Here, the authors develop a new deep learning method for transfer learning from low-cost and abundant data to enhance the efficiency of drug discovery.
- David Buterez
- , Jon Paul Janet
- & Pietro Lió
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Article
| Open AccessIndication of critical scaling in time during the relaxation of an open quantum system
The dynamics of a quantum system shows interesting features. Here the authors demonstrate critical scaling in the spin relaxation due to spin-exchange process in a system of impurity Cs atoms immersed in Rb atoms.
- Ling-Na Wu
- , Jens Nettersheim
- & Artur Widera
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Article
| Open AccessPractical high-dimensional quantum key distribution protocol over deployed multicore fiber
High-dimensional QKD would in principle allow for several advantages over its bidimensional counterpart, but in-the-field demonstrations are missing. Here, the authors realise 4- dimensional hybrid time-path-encoded QKD using a 52-km deployed multicore fiber link.
- Mujtaba Zahidy
- , Domenico Ribezzo
- & Davide Bacco
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Article
| Open AccessAutonomous error correction of a single logical qubit using two transmons
Autonomous quantum error correction protects quantum systems against decoherence through engineered dissipation. Here the authors introduce the Star code, which actively corrects single-photon loss and passively suppresses low-frequency dephasing and implement it in a two-transmon device.
- Ziqian Li
- , Tanay Roy
- & David I. Schuster
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Article
| Open AccessReal-time two-axis control of a spin qubit
Real-time adaptive control of a qubit has been demonstrated but limited to single-axis Hamiltonian estimation. Here the authors implement two-axis control of a singlet-triplet spin qubit with two fluctuating Hamiltonian parameters, resulting in improved quality of coherent oscillations.
- Fabrizio Berritta
- , Torbjørn Rasmussen
- & Ferdinand Kuemmeth
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Article
| Open AccessEnhancing detection of topological order by local error correction
Detection of topological phases in experiments is challenging, especially in the presence of incoherent noise. Cong et al. introduce a novel method combining error correction and renormalization-group flow and apply it to characterization of quantum spin liquid phases realized in a Rydberg-atom simulator.
- Iris Cong
- , Nishad Maskara
- & Mikhail D. Lukin