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Robust classification of salient links in complex networks
Methods to study the structure of complex networks often rely on case-sensitive parameters that have limited applications. In this study, a new method—link salience—is used to classify network elements based on a consensus estimate of all nodes, finding generic topological features in many empirical networks.
- Daniel Grady
- , Christian Thiemann
- & Dirk Brockmann
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Dark acoustic metamaterials as super absorbers for low-frequency sound
Metamaterials can be used to alter the transmission of light or sound, with their tailored structures permitting control over their optical or acoustic properties. Meiet al. present a thin-film acoustic metamaterial that provides efficient absorption of sound over a broad range of wavelengths.
- Jun Mei
- , Guancong Ma
- & Ping Sheng
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| Open AccessResolving the electromagnetic mechanism of surface-enhanced light scattering at single hot spots
Light scattering from nanoscale objects can be dramatically enhanced in the proximity of optical antennas. Here, by studying the amplitude and phase of the light scattered from a tip located at the hot spot of an antenna, the underlying electromagnetic mechanism of this enhancement is resolved.
- P. Alonso-González
- , P. Albella
- & R. Hillenbrand
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Ultrafast heating as a sufficient stimulus for magnetization reversal in a ferrimagnet
The dynamics of spin ordering in magnetic materials is of interest both from a fundamental and an applied point of view. Using a combination of numerical and experimental techniques, Ostleret al. show that the magnetization of a ferrimagnet can be reversed on a timescale of picoseconds solely by heating it.
- T.A. Ostler
- , J. Barker
- & A.V. Kimel
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Propagation stability of self-reconstructing Bessel beams enables contrast-enhanced imaging in thick media
Self-reconstructing laser beams can propagate deep into thick media, making them ideal for light-sheet microscopy of organic matter. By considering the rings of self-reconstructing Bessel beams, Fahrbach and Rohrbach present a technique for improving the contrast and resolution of this approach.
- Florian O. Fahrbach
- & Alexander Rohrbach
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| Open AccessConclusive quantum steering with superconducting transition-edge sensors
Untrustworthy sources or detectors mean that quantum entanglement cannot always be ensured, but quantum steering inequalities can verify its presence. Using a highly efficient system, Smithet al. are able to close the detection loophole and clearly demonstrate steering between two parties.
- Devin H. Smith
- , Geoff Gillett
- & Andrew G. White
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| Open AccessMeasurement of finite-frequency current statistics in a single-electron transistor
Fluctuations of the electrical current in nanoscale devices reveal important details of the physical processes occurring inside them. Using a quantum point contact placed in its vicinity, Ubbelohde et al. measure the electrical fluctuations in a single-electron transistor, and determine the dynamical features of the transport.
- Niels Ubbelohde
- , Christian Fricke
- & Rolf J. Haug
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| Open AccessExtraordinary carrier multiplication gated by a picosecond electric field pulse
Studying carrier multiplication in materials is important to understand their transport properties and interaction with light. Hiroriet al. show that intense terahertz pulses can generate electron-hole pairs in GaAs quantum wells that then emit infrared light, contrary to the effect with a DC field.
- H. Hirori
- , K. Shinokita
- & K. Tanaka
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Inverse barocaloric effect in the giant magnetocaloric La–Fe–Si–Co compound
When materials change temperature as a result of the application of pressure or a change in the magnetization, they are said to display a barocaloric or magnetocaloric effect, respectively. This study reports a substantial barocaloric effect in the giant magnetocaloric material LaFe11.33Co0.47Si1.2.
- Lluís Mañosa
- , David González-Alonso
- & Subham Majumdar
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Interface engineering of quantum Hall effects in digital transition metal oxide heterostructures
Topological insulators are a class of materials with an unusual band structure that makes them metallic at the surface and insulating in the bulk. Okamoto and co-workers use electronic structure calculations to predict a new family of possible topological insulators based on transition-metal oxides.
- Di Xiao
- , Wenguang Zhu
- & Satoshi Okamoto
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| Open AccessObservation of an anomalous decoherence effect in a quantum bath at room temperature
Quantum objects are subject to decoherence effects due to the surrounding environment. This study demonstrates experimentally a counterintuitive example of anomalous decoherence, in which electron spins residing at nitrogen vacancy centres in diamond display longer coherence times under stronger noises.
- Pu Huang
- , Xi Kong
- & Jiangfeng Du
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| Open AccessGraphene chiral liquid crystals and macroscopic assembled fibres
Chiral liquid crystals of two-dimensional colloids have not been extensively investigated. Xu and Gao show that graphene oxide can form chiral liquid crystals, and demonstrate that they can be spun into macroscopic fibres, and that subsequent chemical reduction provides graphene fibres with high conductivity.
- Zhen Xu
- & Chao Gao
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| Open AccessSuppression of the intrinsic stochastic pinning of domain walls in magnetic nanostripes
The propagation of magnetic domain walls in nanowires offers promise as the basis of future memory storage technologies. Muñoz and Prieto show that the random pinning of domain walls to structural defects in the nanowires can be suppressed at low fields, thus improving the reliability of the transmission of the domain walls substantially.
- Manuel Muñoz
- & José L. Prieto
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Concurrent transition of ferroelectric and magnetic ordering near room temperature
Magnetoelectric materials combine ferroelectric and magnetic properties through a coupling of the spin and lattice degrees of freedom. Here, magnetoelectric bismuth ferrite is found to simultaneously undergo both a magnetic and a ferroelectric transition at the same temperature.
- Kyung-Tae Ko
- , Min Hwa Jung
- & Chan-Ho Yang
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| Open AccessA new regime for mechanical annealing and strong sample-size strengthening in body centred cubic molybdenum
Mechanical annealing is a process through which the dislocation density in submicrometre metal crystals can be removed purely by applying a mechanical stress. This study shows that mechanical annealing occurs in body centred cubic molybdenum, and not only in face centred crystals as previously thought.
- Ling Huang
- , Qing-Jie Li
- & Evan Ma
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| Open AccessCoupling artificial molecular spin states by photon-assisted tunnelling
Tunnelling transitions triggered by microwave irradiation between coupled quantum dots have generally been assumed to be spin-conserving. This study shows that this condition is violated in the presence of spin–orbit coupling, thus opening new possibilities for manipulating a two–spin qubit system by microwave irradiation.
- L.R. Schreiber
- , F.R. Braakman
- & L.M.K. Vandersypen
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| Open AccessHigh-density magnetoresistive random access memory operating at ultralow voltage at room temperature
Magnetoresistive random access memory offers significant promise as a next-generation memory technology. Nan and colleagues present a design concept for a device that simultaneously possesses ultrahigh storage capacity, ultralow power dissipation, and high-speed operation at room temperature.
- Jia-Mian Hu
- , Zheng Li
- & Ce-Wen Nan
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| Open AccessElectric field-induced chemical locomotion of conducting objects
External electric fields have been used to control the motion of small objects through electrostatic repulsion. Here, electric fields are used to polarize conducting objects, triggering their movement by spatially separated electrochemical reactions leading to directionally controlled bubble evolution.
- Gabriel Loget
- & Alexander Kuhn
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Super-resolution surface mapping using the trajectories of molecular probes
Surface characterization of soft materialsin situis challenging due to the importance of non-covalent interactions. Now, a new chemical imaging method is reported that generates images of surface interactions by combining many molecular probe trajectories.
- Robert Walder
- , Nathaniel Nelson
- & Daniel K. Schwartz
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Broadband polarization-independent resonant light absorption using ultrathin plasmonic super absorbers
Plasmonic nanostructures and metamaterials can augment the performance of photovoltaic and thermophotovoltaic cells by enhancing their absorption properties. Aydinet al. demonstrate a broadband, ultrathin plasmonic super absorber using crossed trapezoids as part of a metal–insulator–metal stack.
- Koray Aydin
- , Vivian E. Ferry
- & Harry A. Atwater
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Field-effect reconfigurable nanofluidic ionic diodes
Nanofluidic diodes are utilized for the rectification of ionic transport, but their rectifying properties cannot be altered after the devices are made. Here, a field-effect reconfigurable nanofluidic diode is reported in which the forward direction and the degree of rectification can be modulated by a gate voltage.
- Weihua Guan
- , Rong Fan
- & Mark A. Reed
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Control of electronic conduction at an oxide heterointerface using surface polar adsorbates
The interfaces between complex oxides can play host to a range of interesting electronic phenomena. Xieet al. demonstrate that the electronic properties at the LaAlO3/SrTiO3interface can be tuned upon application of common polar solvents such as acetone, ethanol and water.
- Yanwu Xie
- , Yasuyuki Hikita
- & Harold Y. Hwang
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| Open AccessRole of mid-gap states in charge transport and photoconductivity in semiconductor nanocrystal films
Nanocrystals are used in light-emitting diodes and solar cells, but their charge transport in films is unclear. Here, the study of PbS nanocrystal films reveals the role of mid-gap states in their charge transport, suggesting different design needs for devices operated in dark (transistors) versus light (solar cells) conditions.
- Prashant Nagpal
- & Victor I. Klimov
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| Open AccessDetecting inertial effects with airborne matter-wave interferometry
Inertial sensors using atom interferometry have applications in geophysics, navigation- and space-based tests of fundamental physics. Here, the first operation of an atom accelerometer during parabolic flights is reported, demonstrating high-resolution measurements at both 1g and 0g.
- R. Geiger
- , V. Ménoret
- & P. Bouyer
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| Open AccessInformation processing using a single dynamical node as complex system
The paradigm of reservoir computing shows that, like the human brain, complex networks can perform efficient information processing. Here, a simple delay dynamical system is demonstrated that can efficiently perform computations capable of replacing a complex network in reservoir computing.
- L. Appeltant
- , M.C. Soriano
- & I. Fischer
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Microfluidic quadrupole and floating concentration gradient
Quadrupoles have many engineering applications, but experimental observations of fluidic multipoles have not been reported. This study presents an experimental two-dimensional microfluidic quadrupole, a theoretical analysis consistent with observations, and a first application as a channel-free floating gradient generator.
- Mohammad A. Qasaimeh
- , Thomas Gervais
- & David Juncker
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Surfactant-enabled epitaxy through control of growth mode with chemical boundary conditions
Property coupling by heteroepitaxy is severely limited in material combinations with highly dissimilar bonding. This report presents a chemical boundary condition methodology to actively engineer two-dimensional film growth in such systems that otherwise collapse into island formation and rough morphologies.
- Elizabeth A. Paisley
- , Mark. D. Losego
- & Jon-Paul Maria
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| Open AccessBethe-hole polarization analyser for the magnetic vector of light
Determining the direction of the magnetic field of light is important for optical applications. Here, scattering of light from a subwavelength aperture in a metal plane is shown to be governed by its magnetic vector, providing the magnetic field orientation independently of the electric field.
- H.W. Kihm
- , S.M. Koo
- & D.-S. Kim
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| Open AccessFast cavity-enhanced atom detection with low noise and high fidelity
Single atoms can be detected using optical resonators that extend the lifetime of the photon. Here, the authors demonstrate fast, high-fidelity detection of very low atom densities using a microfabricated optical cavity to couple the detection light with the atoms.
- J. Goldwin
- , M. Trupke
- & E.A. Hinds
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| Open AccessAdding control to arbitrary unknown quantum operations
Quantum computing has advantages over conventional computing, but the complexity of quantum algorithms creates technological challenges. Here, an architecture-independent technique, that simplifies adding control qubits to arbitrary quantum operations, is developed and demonstrated.
- Xiao-Qi Zhou
- , Timothy C. Ralph
- & Jeremy L. O'Brien
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| Open AccessSize limits the formation of liquid jets during bubble bursting
A bubble at an air–liquid interface can form a liquid jet upon bursting, spraying aerosol droplets into the air. Leeet al. show that jetting is analogous to pinching-off in liquid coalescence, which may be useful in applications that prevent jet formation and in the improved incorporation of aerosols in climate models.
- Ji San Lee
- , Byung Mook Weon
- & Wah-Keat Lee
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| Open AccessThe vectorial control of magnetization by light
Light–matter interactions can be used to manipulate magnetization in solids, but light-controlled magnetization vector motion has not been demonstrated. Here, two-dimensional magnetic oscillations in NiO are manipulated with optical pulses leading to vectorial control of magnetization by light.
- Natsuki Kanda
- , Takuya Higuchi
- & Makoto Kuwata-Gonokami
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Observing chaos for quantum-dot microlasers with external feedback
Optoelectronic devices such as conventional semiconductor lasers are used to study the chaotic behaviour of nonlinear systems. Here chaos is observed for quantum-dot microlasers operating close to the quantum limit with potential for new directions in the study of chaos in quantum systems.
- Ferdinand Albert
- , Caspar Hopfmann
- & Ido Kanter
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| Open AccessColossal negative thermal expansion in BiNiO3 induced by intermetallic charge transfer
Negative thermal expansion—contraction upon heating—is an unusual process that may be exploited to produce materials with zero or other controlled thermal expansion values. Azumaet al. observe negative thermal expansion in BiNiO3which is a result of Bi/Ni charge-transfer transitions.
- Masaki Azuma
- , Wei-tin Chen
- & J. Paul Attfield
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| Open AccessActive microrheology and simultaneous visualization of sheared phospholipid monolayers
Two-dimensional fluid interfaces are ubiquitous, but studying their surface dynamic properties is difficult because of coupling between the film and bulk fluid. Choiet al.combine active microrheology with fluorescence microscopy to image fluid interfaces under applied stress.
- S.Q. Choi
- , S. Steltenkamp
- & T.M. Squires
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| Open AccessRevealing the molecular structure of single-molecule junctions in different conductance states by fishing-mode tip-enhanced Raman spectroscopy
The conductance of single-molecule junctions is affected by the structure of the molecule and how it is bound to the electrodes, which may be examined using Raman spectroscopy. Liuet al. have developed 'fishing-mode' tip-enhanced Raman spectroscopy, which allows the simultaneous determination of conductance and Raman spectra.
- Zheng Liu
- , Song-Yuan Ding
- & Zhong-Qun Tian
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Cooperative material transport during the early stage of sintering
Sintering is the basis for the production of many metallic and composite materials. Gruppet al. use a new technique to measure the rotation of microscopic copper particles during sintering and find intrinsic rotations to be the dominant movement.
- R. Grupp
- , M. Nöthe
- & J. Banhart
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| Open AccessTravelling-wave resonant four-wave mixing breaks the limits of cavity-enhanced all-optical wavelength conversion
Wave mixing in optical resonators suffers from strong bandwidth constraints, hindering practical implementation. Morichettiet al. report travelling-wave four-wavemixing in coupled ring resonators, which combines the efficiency enhancement of resonant propagation with a wide-band conversion process.
- Francesco Morichetti
- , Antonio Canciamilla
- & Andrea Melloni
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| Open AccessReversible temperature regulation of electrical and thermal conductivity using liquid–solid phase transitions
Temperature-controlled regulation of thermal conductivity is difficult to achieve because thermal properties do not change significantly through solid-state phase transitions. Here temperature control of thermal conductivities is demonstrated using liquid–solid phase transitions in a nanoparticle suspension.
- Ruiting Zheng
- , Jinwei Gao
- & Gang Chen
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Size and mechanics effects in surface-induced melting of nanoparticles
Melting-related phenomena are of fundamental and applied interest, but the melting theory is poorly understood. Levitas and Samani develop an advanced phase-field theory of melting coupled to mechanics that resolves existing contradictions and reveals the features of melting phenomena.
- Valery I Levitas
- & Kamran Samani
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| Open AccessWhispering gallery microresonators for second harmonic light generation from a low number of small molecules
Small molecules can be detected by second harmonic light generation, but sensitive detection usually requires a large number of molecules and a high-power laser source. Here, relatively low numbers of molecules are detected using Q spherical microresonators and low average power.
- J.L. Dominguez-Juarez
- , G. Kozyreff
- & Jordi Martorell
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A nanomechanical interface to rapid single-molecule interactions
Single-molecule force spectroscopy is used to study single molecule interactions, but probing short-lived events is difficult. Here, a nanomechanical interface is developed, which allows the study of microsecond timescale interactions.
- Mingdong Dong
- & Ozgur Sahin
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Electrical injection and detection of spin accumulation in silicon at 500 K with magnetic metal/silicon dioxide contacts
Harnessing spin angular momentum could allow the development of electronic devices that are not limited by Moore's law. Here, electrical injection and detection of spin accumulation is achieved at temperatures that are practical for device operation.
- C.H. Li
- , O.M.J. van 't Erve
- & B.T. Jonker
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Nanofriction in cold ion traps
Cold ion traps have not previously been used to study sliding friction between crystal lattices. Here, Benassiet al. use simulations to show that cold ion traps could be used for detailed investigation of atomic scale friction.
- A. Benassi
- , A. Vanossi
- & E. Tosatti
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| Open AccessPhonon-tunnelling dissipation in mechanical resonators
The performance of micromechanical and nanomechanical resonators is often hampered by mechanical damping. In this study, the authors demonstrate a numerical solver for the prediction of support-induced losses in these structures and verify experimentally the fidelity of this method.
- Garrett D. Cole
- , Ignacio Wilson-Rae
- & Markus Aspelmeyer
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| Open AccessMultimode quantum interference of photons in multiport integrated devices
Multimode interference devices could allow the implementation of multiport circuits for quantum technologies. Here, quantum interference is demonstrated in 2×2 and 4×4 multimode interference devices, and a technique is reported to characterize such devices.
- Alberto Peruzzo
- , Anthony Laing
- & Jeremy L. O'Brien
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| Open AccessA fast and low-power microelectromechanical system-based non-volatile memory device
New memory devices are being developed to overcome the limitations of conventional silicon-based flash memory. Here, a non-volatile memory design is reported that uses a micromechanical cantilever to charge and discharge a floating gate, which controls charge transport through a carbon nanotube field-effect transistor.
- Sang Wook Lee
- , Seung Joo Park
- & Yung Woo Park
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| Open AccessInterconnect-free parallel logic circuits in a single mechanical resonator
Eliminating wiring in transistors could lead to high integration densities and low power consumption. Here, multiple logic gates are implemented in a microelectromechanical resonator by parametrically mixing binary information channels corresponding to mechanical oscillations of the resonator at different frequencies.
- I. Mahboob
- , E. Flurin
- & H. Yamaguchi
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Spherical hyperlens for two-dimensional sub-diffractional imaging at visible frequencies
Although hyperlenses made of metamaterials can image sub-diffraction-limited objects, they are limited to one-dimensional magnification and ultraviolet frequencies. Here, the authors demonstrate a spherical hyperlens for visible light far-field imaging, with a resolution of 160 nm in both lateral dimensions.
- Junsuk Rho
- , Ziliang Ye
- & Xiang Zhang