EPJ Quantum Technology最新文献

{"title":"Enhanced Hanbury Brown and Twiss interferometry using parametric amplification","authors":"Xiaoping Ma,&nbsp;Chenglong You,&nbsp;Sushovit Adhikari,&nbsp;Yongjian Gu,&nbsp;Omar S. Magaña-Loaiza,&nbsp;Jonathan P. Dowling,&nbsp;Hwang Lee","doi":"10.1140/epjqt/s40507-020-00085-5","DOIUrl":"https://doi.org/10.1140/epjqt/s40507-020-00085-5","url":null,"abstract":"<p>The Hanbury Brown and Twiss (HBT) interferometer was proposed to observe intensity correlations of starlight to measure a star’s angular diameter. As the intensity of light that reaches the detector from a star is very weak, one cannot usually get a workable signal-to-noise ratio. We propose an improved HBT interferometric scheme incorporating optical parametric amplifiers (OPA) into the system to amplify the correlation signal. Remarkably, for weak star light, the signal-to-noise ratio (SNR) in the new HBT interferometric scheme is much better than that of conventional HBT interferometer. Our work is valuable in measuring a star whose intensity at the detector is low and maybe also applicable in remote sensing and long-distance quantum imaging where the light passed through the object is weak after a long distance transmission.</p>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"7 1","pages":""},"PeriodicalIF":5.3,"publicationDate":"2020-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5120954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Second-order effects in parametric-resonance magnetometers based on atomic alignment","authors":"François Beato,&nbsp;Agustin Palacios-Laloy","doi":"10.1140/epjqt/s40507-020-00083-7","DOIUrl":"https://doi.org/10.1140/epjqt/s40507-020-00083-7","url":null,"abstract":"<p>Optically-pumped magnetometers (OPM) based on parametric resonance allow real-time tri-axial measurement of very small magnetic fields with a single optical access to the gas cell. Most of these magnetometers rely on circularly polarized pumping light. We focus here on the ones relying on linearly polarized light, yielding atomic alignment. For these magnetometers we investigate three second order effects which appear in the usual regimes of operation, so to clarify if they translate to metrological problems like systematic errors or increased noise. The first of these effects is the breakdown of the three-step approach when the optical beam has a large intensity. The second one is the breakdown of the rotating wave approximation when the frequencies of the RF fields are not much larger than the rates of other atomic processes. The third one is the tensor light-shift which appears when the light is slightly detuned from resonance. This work should help to clarify the accuracy reachable with OPM, which is an important question notably for medical imaging applications.</p>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"7 1","pages":""},"PeriodicalIF":5.3,"publicationDate":"2020-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4312596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A quantum key distribution protocol for rapid denial of service detection","authors":"Alasdair B. Price,&nbsp;John G. Rarity,&nbsp;Chris Erven","doi":"10.1140/epjqt/s40507-020-00084-6","DOIUrl":"https://doi.org/10.1140/epjqt/s40507-020-00084-6","url":null,"abstract":"<p>We introduce a quantum key distribution protocol designed to expose fake users that connect to Alice or Bob for the purpose of monopolising the link and denying service. It inherently resists attempts to exhaust Alice and Bob’s initial shared secret and is 100% efficient, regardless of the number of qubits exchanged above the finite key limit. Additionally, secure key can be generated from two-photon pulses without having to make any extra modifications. This is made possible by relaxing the security of BB84 to that of the quantum-safe block cipher used for day-to-day encryption, meaning the overall security remains unaffected for useful real-world cryptosystems such as AES-GCM being keyed with quantum devices.</p>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"7 1","pages":""},"PeriodicalIF":5.3,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4045830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Niobium quarter-wave resonator with the optimized shape for quantum information systems","authors":"S. V. Kutsaev,&nbsp;K. Taletski,&nbsp;R. Agustsson,&nbsp;P. Carriere,&nbsp;A. N. Cleland,&nbsp;Z. A. Conway,&nbsp;É. Dumur,&nbsp;A. Moro,&nbsp;A. Yu. Smirnov","doi":"10.1140/epjqt/s40507-020-00082-8","DOIUrl":"https://doi.org/10.1140/epjqt/s40507-020-00082-8","url":null,"abstract":"<p>Quantum computers (QC), if realized, could disrupt many computationally intense fields of science. The building block element of a QC is a quantum bit (qubit). Qubits enable the use of quantum superposition and multi-state entanglement in QC calculations, allowing a QC to simultaneously perform millions of computations at once. However, quantum states stored in a qubit degrade with decreased quality factors and interactions with the environment. One technical solution to improve qubit lifetimes and network interactions is a circuit comprised of a Josephson junction-based qubit located inside of a high Q-factor superconducting 3D cavity.</p><p>It is known that niobium resonators can reach <span>(Q_{0}&gt;10^{11})</span>. However, existing cavity geometries are optimized for particle acceleration rather than hosting qubits. RadiaBeam Technologies, in collaboration with Argonne National Laboratory and The University of Chicago, has developed a niobium superconducting radio frequency quarter-wave resonant cavity (QWR) for quantum computation. A 6?GHz QWR was optimized to include tapering of the inner and outer conductors, a toroidal shape for the resonator shorting plane, and an inner conductor tip to reduce parasitic capacitance. In this paper, we present the results of the resonator design optimization, fabrication, processing, and testing.</p>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"7 1","pages":""},"PeriodicalIF":5.3,"publicationDate":"2020-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4670506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"AEDGE: Atomic Experiment for Dark Matter and Gravity Exploration in Space","authors":"Yousef Abou El-Neaj,&nbsp;Cristiano Alpigiani,&nbsp;Sana Amairi-Pyka,&nbsp;Henrique Araújo,&nbsp;Antun Balaž,&nbsp;Angelo Bassi,&nbsp;Lars Bathe-Peters,&nbsp;Baptiste Battelier,&nbsp;Aleksandar Belić,&nbsp;Elliot Bentine,&nbsp;José Bernabeu,&nbsp;Andrea Bertoldi,&nbsp;Robert Bingham,&nbsp;Diego Blas,&nbsp;Vasiliki Bolpasi,&nbsp;Kai Bongs,&nbsp;Sougato Bose,&nbsp;Philippe Bouyer,&nbsp;Themis Bowcock,&nbsp;William Bowden,&nbsp;Oliver Buchmueller,&nbsp;Clare Burrage,&nbsp;Xavier Calmet,&nbsp;Benjamin Canuel,&nbsp;Laurentiu-Ioan Caramete,&nbsp;Andrew Carroll,&nbsp;Giancarlo Cella,&nbsp;Vassilis Charmandaris,&nbsp;Swapan Chattopadhyay,&nbsp;Xuzong Chen,&nbsp;Maria Luisa Chiofalo,&nbsp;Jonathon Coleman,&nbsp;Joseph Cotter,&nbsp;Yanou Cui,&nbsp;Andrei Derevianko,&nbsp;Albert De Roeck,&nbsp;Goran S. Djordjevic,&nbsp;Peter Dornan,&nbsp;Michael Doser,&nbsp;Ioannis Drougkakis,&nbsp;Jacob Dunningham,&nbsp;Ioana Dutan,&nbsp;Sajan Easo,&nbsp;Gedminas Elertas,&nbsp;John Ellis,&nbsp;Mai El Sawy,&nbsp;Farida Fassi,&nbsp;Daniel Felea,&nbsp;Chen-Hao Feng,&nbsp;Robert Flack,&nbsp;Chris Foot,&nbsp;Ivette Fuentes,&nbsp;Naceur Gaaloul,&nbsp;Alexandre Gauguet,&nbsp;Remi Geiger,&nbsp;Valerie Gibson,&nbsp;Gian Giudice,&nbsp;Jon Goldwin,&nbsp;Oleg Grachov,&nbsp;Peter W. Graham,&nbsp;Dario Grasso,&nbsp;Maurits van der Grinten,&nbsp;Mustafa Gündogan,&nbsp;Martin G. Haehnelt,&nbsp;Tiffany Harte,&nbsp;Aurélien Hees,&nbsp;Richard Hobson,&nbsp;Jason Hogan,&nbsp;Bodil Holst,&nbsp;Michael Holynski,&nbsp;Mark Kasevich,&nbsp;Bradley J. Kavanagh,&nbsp;Wolf von Klitzing,&nbsp;Tim Kovachy,&nbsp;Benjamin Krikler,&nbsp;Markus Krutzik,&nbsp;Marek Lewicki,&nbsp;Yu-Hung Lien,&nbsp;Miaoyuan Liu,&nbsp;Giuseppe Gaetano Luciano,&nbsp;Alain Magnon,&nbsp;Mohammed Attia Mahmoud,&nbsp;Sarah Malik,&nbsp;Christopher McCabe,&nbsp;Jeremiah Mitchell,&nbsp;Julia Pahl,&nbsp;Debapriya Pal,&nbsp;Saurabh Pandey,&nbsp;Dimitris Papazoglou,&nbsp;Mauro Paternostro,&nbsp;Bjoern Penning,&nbsp;Achim Peters,&nbsp;Marco Prevedelli,&nbsp;Vishnupriya Puthiya-Veettil,&nbsp;John Quenby,&nbsp;Ernst Rasel,&nbsp;Sean Ravenhall,&nbsp;Jack Ringwood,&nbsp;Albert Roura,&nbsp;Dylan Sabulsky,&nbsp;Muhammed Sameed,&nbsp;Ben Sauer,&nbsp;Stefan Alaric Schäffer,&nbsp;Stephan Schiller,&nbsp;Vladimir Schkolnik,&nbsp;Dennis Schlippert,&nbsp;Christian Schubert,&nbsp;Haifa Rejeb Sfar,&nbsp;Armin Shayeghi,&nbsp;Ian Shipsey,&nbsp;Carla Signorini,&nbsp;Yeshpal Singh,&nbsp;Marcelle Soares-Santos,&nbsp;Fiodor Sorrentino,&nbsp;Timothy Sumner,&nbsp;Konstantinos Tassis,&nbsp;Silvia Tentindo,&nbsp;Guglielmo Maria Tino,&nbsp;Jonathan N. Tinsley,&nbsp;James Unwin,&nbsp;Tristan Valenzuela,&nbsp;Georgios Vasilakis,&nbsp;Ville Vaskonen,&nbsp;Christian Vogt,&nbsp;Alex Webber-Date,&nbsp;André Wenzlawski,&nbsp;Patrick Windpassinger,&nbsp;Marian Woltmann,&nbsp;Efe Yazgan,&nbsp;Ming-Sheng Zhan,&nbsp;Xinhao Zou,&nbsp;Jure Zupan","doi":"10.1140/epjqt/s40507-020-0080-0","DOIUrl":"https://doi.org/10.1140/epjqt/s40507-020-0080-0","url":null,"abstract":"<p>We propose in this White Paper a concept for a space experiment using cold atoms to search for ultra-light dark matter, and to detect gravitational waves in the frequency range between the most sensitive ranges of LISA and the terrestrial LIGO/Virgo/KAGRA/INDIGO experiments. This interdisciplinary experiment, called Atomic Experiment for Dark Matter and Gravity Exploration (AEDGE), will also complement other planned searches for dark matter, and exploit synergies with other gravitational wave detectors. We give examples of the extended range of sensitivity to ultra-light dark matter offered by AEDGE, and how its gravitational-wave measurements could explore the assembly of super-massive black holes, first-order phase transitions in the early universe and cosmic strings. AEDGE will be based upon technologies now being developed for terrestrial experiments using cold atoms, and will benefit from the space experience obtained with, e.g., LISA and cold atom experiments in microgravity.</p><p>KCL-PH-TH/2019-65, CERN-TH-2019-126</p>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"7 1","pages":""},"PeriodicalIF":5.3,"publicationDate":"2020-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4176653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Applying the matched-filter technique to the search for dark matter transients with networks of quantum sensors","authors":"Guglielmo Panelli,&nbsp;Benjamin M. Roberts,&nbsp;Andrei Derevianko","doi":"10.1140/epjqt/s40507-020-00081-9","DOIUrl":"https://doi.org/10.1140/epjqt/s40507-020-00081-9","url":null,"abstract":"<p>There are several networks of precision quantum sensors in existence, including networks of atomic clocks, magnetometers, and gravitational wave detectors. These networks can be re-purposed for searches of exotic physics, such as direct dark matter searches. Here we explore a detection strategy for macroscopic dark matter objects with such networks using the matched-filter technique. Such “clumpy” dark matter objects would register as transients sweeping through the network at galactic velocities. As a specific example, we consider a network of atomic clocks aboard the Global Positioning System (GPS) satellites. We apply the matched-filter technique to simulated GPS atomic clock data and study its utility and performance. The analysis and the developed methodology have a discovery reach up to three orders of magnitude above the previous GPS results and have a wide applicability to other networks of quantum sensors.</p>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"7 1","pages":""},"PeriodicalIF":5.3,"publicationDate":"2020-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4822890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Scheduling of space to ground quantum key distribution","authors":"Mateusz Polnik,&nbsp;Luca Mazzarella,&nbsp;Marilena Di Carlo,&nbsp;Daniel KL Oi,&nbsp;Annalisa Riccardi,&nbsp;Ashwin Arulselvan","doi":"10.1140/epjqt/s40507-020-0079-6","DOIUrl":"https://doi.org/10.1140/epjqt/s40507-020-0079-6","url":null,"abstract":"<p>Satellite-based platforms are currently the only feasible way of achieving intercontinental range for quantum communication, enabling thus the future global quantum internet. Recent demonstrations by the Chinese spacecraft Micius have spurred an international space race and enormous interest in the development of both scientific and commercial systems. Research efforts so far have concentrated upon in-orbit demonstrations involving a single satellite and one or two ground stations. Ultimately satellite quantum key distribution should enable secure network communication between multiple nodes, which requires efficient scheduling of communication with the set of ground stations. Here we present a study of how satellite quantum key distribution can service many ground stations taking into account realistic constraints such as geography, operational hours, and most importantly, weather conditions. The objective is to maximise the number of keys a set of ground stations located in the United Kingdom could share while simultaneously reflecting the communication needs of each node and its relevance in the network. The problem is formulated as a mixed-integer linear optimisation program and solved to a desired optimality gap using a state of the art solver. The approach is presented using a simulation run throughout six years to investigate the total number of keys that can be sent to ground stations.</p>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"7 1","pages":""},"PeriodicalIF":5.3,"publicationDate":"2020-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1140/epjqt/s40507-020-0079-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5174400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sensing microwave photons with a Bose–Einstein condensate","authors":"Orsolya Kálmán,&nbsp;Peter Domokos","doi":"10.1140/epjqt/s40507-020-0078-7","DOIUrl":"https://doi.org/10.1140/epjqt/s40507-020-0078-7","url":null,"abstract":"<p>We consider the interaction of a magnetically trapped Bose–Einstein condensate of Rubidium atoms with the stationary microwave radiation field sustained by a coplanar waveguide resonator. This coupling allows for the measurement of the magnetic field of the resonator by means of counting the atoms that fall out of the condensate due to hyperfine transitions to non-trapped states. We determine the quantum efficiency of this detection scheme and show that weak microwave fields at the single-photon level can be sensed.</p>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"7 1","pages":""},"PeriodicalIF":5.3,"publicationDate":"2020-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1140/epjqt/s40507-020-0078-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4604768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A similarity of quantum phase transition and quench dynamics in the Dicke model beyond the thermodynamic limit","authors":"Lituo Shen,&nbsp;Zhicheng Shi,&nbsp;Zhenbiao Yang,&nbsp;Huaizhi Wu,&nbsp;Zhirong Zhong,&nbsp;Shibiao Zheng","doi":"10.1140/epjqt/s40507-019-0077-8","DOIUrl":"https://doi.org/10.1140/epjqt/s40507-019-0077-8","url":null,"abstract":"<p>We study the quantum phase transition in the Dicke model beyond the thermodynamic limit. With the Kibble–Zurek mechanism and adiabatic dynamics, we find that the residual energy is inversely proportional to the number of qubits, indicating that more qubits can obtain more energies from the oscillator as the number of qubits increases. Finally, we put forward a promising experiment device to realize this system.</p>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"7 1","pages":""},"PeriodicalIF":5.3,"publicationDate":"2020-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1140/epjqt/s40507-019-0077-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4251327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance analysis of an optically pumped magnetometer in Earth’s magnetic field","authors":"Gregor Oelsner,&nbsp;Volkmar Schultze,&nbsp;Rob IJsselsteijn,&nbsp;Ronny Stolz","doi":"10.1140/epjqt/s40507-019-0076-9","DOIUrl":"https://doi.org/10.1140/epjqt/s40507-019-0076-9","url":null,"abstract":"<p>We experimentally investigate the influence of the orientation of optically pumped magnetometers in Earth’s magnetic field. We focus our analysis to an operational mode that promises femtotesla field resolutions at such field strengths. For this so-called light-shift dispersed <span>(M_{z})</span> (LSD-Mz) regime, we focus on the key parameters defining its performance. That are the reconstructed Larmor frequency, the transfer function between output signal and magnetic field amplitude as well as the shot noise limited field resolution. We demonstrate that due to the use of two well balanced laser beams for optical pumping with different helicities the heading error as well as the field sensitivity of a detector both are only weakly influenced by the heading in a large orientation angle range.</p>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":"6 1","pages":""},"PeriodicalIF":5.3,"publicationDate":"2019-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1140/epjqt/s40507-019-0076-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4489581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}