Single photons and quantum effects articles within Nature Communications

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  • Article
    | Open Access

    An efficient way of realising a large number of telecom single-photon emitters for quantum communication is still missing. Here, the authors use a wide-field imaging technique for fast localization of single InAs/InP quantum dots, which are then integrated into circular Bragg grating cavities featuring high single-photon purity and indistinguishability.

    • Paweł Holewa
    • , Daniel A. Vajner
    •  & Elizaveta Semenova
  • Article
    | Open Access

    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
  • Article
    | Open Access

    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
  • Article
    | Open Access

    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
  • Article
    | Open Access

    The authors show an original approach to achieve strong light-matter interaction harnessing the coupling between plasmonic resonators and the Landau resonances of an underlying quantum well, demonstrating remarkably high coupling strengths.

    • Joshua Mornhinweg
    • , Laura Katharina Diebel
    •  & Christoph Lange
  • Article
    | Open Access

    By coupling a spin-qubit to a superconducting resonator, remote spin-entanglement becomes feasible. Here, Ungerer et al achieve strong coupling between a superconducting resonator and a singlet-triplet spin qubit, in an InAs nanowire.

    • J. H. Ungerer
    • , A. Pally
    •  & C. Schönenberger
  • Article
    | Open Access

    Developing quantum networks would require reliable sources of coherent quantum light at telecom wavelengths. Here, the authors employ elastic scattering of excitation laser photons on InAs/InP quantum dots to demonstrate the emission of telecom photons with coherence times longer than the Fourier limit.

    • L. Wells
    • , T. Müller
    •  & A. J. Shields
  • Article
    | Open Access

    High-dimensional quantum states allow for several advantages in quantum communication, but protocols such as teleportation require additional entangled photons as the dimension increases. Here, the authors show how to transport a high-dimensional quantum state from a bright coherent laser field to a single photon, using two entangled photons as the quantum channel.

    • Bereneice Sephton
    • , Adam Vallés
    •  & Andrew Forbes
  • Article
    | Open Access

    Standard techniques for Fluorescence Lifetime Imaging Microscopy are limited by the electronics to 100’s of picoseconds time resolution. Here, the authors show how to use two-photon interference to perform fluorescence lifetime sensing with picosecond-scale resolution.

    • Ashley Lyons
    • , Vytautas Zickus
    •  & Daniele Faccio
  • Article
    | Open Access

    Nonlinear damping is a ubiquitous phenomenon in technological applications involving oscillators, but its origin is sometimes poorly understood. Here, the authors highlight how the interplay between quantum noise and Kerr anharmonicity introduces an effect resembling nonlinear damping.

    • Mario F. Gely
    • , Adrián Sanz Mora
    •  & Gary A. Steele
  • Article
    | Open Access

    Schrodinger’s cat states constitute an important resource for quantum information processing, but present challenges in terms of scalabilty and controllability. Here, the authors exploit fast Kerr nonlinearity modulation to generate and store cat states in superconducting circuits in a more scalable way.

    • X. L. He
    • , Yong Lu
    •  & Z. R. Lin
  • Article
    | Open Access

    Circuit QED with strongly driven cavities is a powerful framework for quantum technologies, but often undesired effects on the qubit are introduced. Here, by using an external tone tailored to destructively interfere with the cavity field, the authors show how a transmon can be protected from these unwanted effects.

    • Cristóbal Lledó
    • , Rémy Dassonneville
    •  & Alexandre Blais
  • Article
    | Open Access

    High-resolution single-photon imaging is challenging due to complex hardware and noise disturbances. Here, the authors realise simultaneous single-photon denoising and super-resolution enhancement by physics-informed deep learning, with a physical multi-source noise model, two single-photon image datasets, and a deep transformer network.

    • Liheng Bian
    • , Haoze Song
    •  & Jun Zhang
  • Article
    | Open Access

    The beamsplitter operation is a key component for quantum information processing, but implementations in superconducting circuit-QED usually introduce additional decoherence. Here, the authors exploit the symmetry within a SQUID, driven in a purely differential manner, to realise clean BS operations between two SC cavity modes.

    • Yao Lu
    • , Aniket Maiti
    •  & Robert J. Schoelkopf
  • Article
    | Open Access

    Hybrid quantum systems, such as superconducting qubits interacting with microwave photons in resonators, offer a rich platform for exploring fundamental physics. Wang et al. observe parity symmetry breaking in a probe qubit dispersively coupled to a resonator in the deep-strong coupling regime.

    • Shuai-Peng Wang
    • , Alessandro Ridolfo
    •  & J. Q. You
  • Article
    | Open Access

    Single-shot readout of optically active spin qubits is typically limited by low photon collection rates and measurement back-action. Here the authors overcome these limitations by using an open cavity approach for single-shot readout of a semiconductor quantum dot and demonstrate record readout time of a few ns.

    • Nadia O. Antoniadis
    • , Mark R. Hogg
    •  & Richard J. Warburton
  • Article
    | Open Access

    Future single-photon-based quantum networks will require both reliable telecom single-photon sources and improvements in security analysis. Here, the authors show how to use quantum dots and difference frequency generation to perform long-distance QKD, also reducing secure key acquisition time thanks to improved analytical bounds.

    • Christopher L. Morrison
    • , Roberto G. Pousa
    •  & Alessandro Fedrizzi
  • Article
    | Open Access

    Squeezed light allows for quantum-enhanced, sub-shot-noise sensing, but its generation and use on a chip has so far remained elusive. Here, the authors fill this gap by demonstrating a thin-film lithium-niobate-based integrated quantum optical sensor, which beats shot-noise-limited SNR by ~ 4%.

    • Hubert S. Stokowski
    • , Timothy P. McKenna
    •  & Amir H. Safavi-Naeini
  • Article
    | Open Access

    Optically active defects in hBN are promising for quantum sensing and information applications, however, coherent control of a single defect has not been achieved so far. By using an efficient method to produce arrays of defects in hBN, Guo et al. isolate a new carbon-related defect and show its coherent control.

    • Nai-Jie Guo
    • , Song Li
    •  & Guang-Can Guo
  • Article
    | Open Access

    The authors present a method for super-resolution quantum microscopy at the Heisenberg limit by using pairs of entangled photons with balanced pathlengths. They improve the spatial resolution, imaging speed, and contrast-to-noise ratio in practice while providing a theoretical interpretation of the super-resolution feature.

    • Zhe He
    • , Yide Zhang
    •  & Lihong V. Wang
  • Article
    | Open Access

    Realising integrated photonic circuits containing isolated telecommunications-wavelength artificial atom single photon emitters is an outstanding challenge in quantum technologies. Here, the authors demonstrate how to embed optically tunable G-centers in silicon-on-insulator integrated circuits.

    • Mihika Prabhu
    • , Carlos Errando-Herranz
    •  & Dirk Englund
  • Article
    | Open Access

    Usually, observation of quantum interference in a non-local scenario (that is, when Alice’s measurement settings and Bob’s outcomes are space-like separated) relies on entanglement. Here, the authors experimentally show four-photon frustrated interference originating from the sources’ indistinguishability, without the need for entanglement.

    • Kaiyi Qian
    • , Kai Wang
    •  & Xiao-song Ma
  • Article
    | Open Access

    The triangle causal structure represents a departure from the usual Bell scenario, as it should allow to violate classical predictions without the need for external inputs setting the measurement bases. Here the authors realise this scenario using a photonic setup with three independent photon sources.

    • Emanuele Polino
    • , Davide Poderini
    •  & Fabio Sciarrino
  • Article
    | Open Access

    Frequency-bin qubits get the best of time-bin and dual-rail encodings, but require external modulators and pulse shapers to build arbitrary states. Here, instead, the authors work directly on-chip by controlling the interference of biphoton amplitudes generated in multiple, coherently-pumped ring resonators.

    • Marco Clementi
    • , Federico Andrea Sabattoli
    •  & Daniele Bajoni
  • Article
    | Open Access

    Quantifying communication capabilities produced by sharing an entangled qubit pair is still a subject of debate. Here the authors show that there are communication tasks for which sharing an entangled pair gives higher power than sharing two classical bits, even when there is no entanglement in the measurements.

    • Amélie Piveteau
    • , Jef Pauwels
    •  & Armin Tavakoli
  • Article
    | Open Access

    The recently demonstrated approaches to fabrication of quantum emitters in silicon result in their random positioning, hindering applications in quantum photonic integrated circuits. Here the authors demonstrate controlled fabrication of telecom-wavelength quantum emitters in silicon wafers by focused ion beams.

    • Michael Hollenbach
    • , Nico Klingner
    •  & Georgy V. Astakhov
  • Article
    | Open Access

    Applications of ultra-low-loss photonic circuitry in quantum photonics, in particular including triggered single photon sources, are rare. Here, the authors show how InAs quantum dot single photon sources can be integrated onto wafer-scale, CMOS compatible ultra-low loss silicon nitride photonic circuits.

    • Ashish Chanana
    • , Hugo Larocque
    •  & Marcelo Davanco
  • Article
    | Open Access

    Quantum bath engineering in the context of circuit quantum electrodynamics typically relies on single-photon losses. Aiello et al. demonstrate an approach for engineering higher-order photon losses in a microwave resonator coupled to a tunnel junction, which may be utilized in quantum information applications.

    • Gianluca Aiello
    • , Mathieu Féchant
    •  & Jérôme Estève
  • Article
    | Open Access

    Hybrid quantum technologies synergistically combine different types of systems with complementary strengths. Here, the authors show monolithic integration and control of quantum dots and the emitted single photons in a surface acoustic wave-driven GaAs integrated quantum photonic circuit.

    • Dominik D. Bühler
    • , Matthias Weiß
    •  & Hubert J. Krenner
  • Article
    | Open Access

    Experimental studies of the Casimir effect have involved only interactions between two bodies so far. Here, the authors observe a micrometer-thick cantilever under the Casimir force exerted by microspheres from two sides simultaneously.

    • Zhujing Xu
    • , Peng Ju
    •  & Tongcang Li
  • Article
    | Open Access

    Fibre-based entanglement distribution represents a key primitive for quantum applications such as QKD. Here, the authors demonstrate it across 248 km of deployed fiber, observing stable detected pair rates of 9 Hz for 110 h.

    • Sebastian Philipp Neumann
    • , Alexander Buchner
    •  & Rupert Ursin
  • Article
    | Open Access

    Successfully controlling an optical signal by a single gate photon would have great applicability for quantum networks and all-optical computing. Here, the authors realise a single-photon transistor in the microwave regime based on superconducting quantum circuits.

    • Zhiling Wang
    • , Zenghui Bao
    •  & Luming Duan
  • Article
    | Open Access

    Vibronic coupling in molecules plays an essential role in photophysics. Here, the authors observe optical fingerprints of the coupling between librational states and charged excited states in a single phthalocyanine molecule chirally absorbed on a surface.

    • Jiří Doležal
    • , Sofia Canola
    •  & Martin Švec
  • Article
    | Open Access

    Sensitivity to noise is currently an obstacle to the use of quantum imaging techniques in real-world scenarios. Here, exploiting non-local cancellation of dispersion on time-frequency entangled photons, the authors show a 43dB improvement in resilience to noise for imaging protocols towards a quantum LiDAR.

    • Phillip S. Blakey
    • , Han Liu
    •  & Amr S. Helmy
  • Article
    | Open Access

    Making Bohmian mechanics fully compatible with special relativity is still an ongoing challenge. Here, the authors make a further step in this direction by providing a way of constructing the relativistic Bohmian-type velocity field of single photons which is operationally based on weak measurements.

    • Joshua Foo
    • , Estelle Asmodelle
    •  & Timothy C. Ralph
  • Comment
    | Open Access

    Controlling dimensionality and strain in actinide heterostructures will provide unrivaled opportunities for exploring novel quantum phenomena. We discuss the promises, challenges, and synthesis routes for these actinide-bearing heterostructures with complex electron correlations for functional and energy materials.

    • Cody A. Dennett
    • , Narayan Poudel
    •  & Krzysztof Gofryk
  • Article
    | Open Access

    Tailoring the properties of single photon emission is a key requirement in photonic quantum technologies. Here, the authors demonstrate frequency and polarisation control of photons emitted from quantum dots through a laser-controlled down-conversion process.

    • B. Jonas
    • , D. Heinze
    •  & A. Zrenner