The thing about data

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p717

doi:10.1038/nphys4238

The rise of big data represents an opportunity for physicists. To take full advantage, however, they need a subtle but important shift in mindset.

Commentary

The physics of data 

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pp718 - 719

Jeff Byers

doi:10.1038/nphys4202

Physicists are accustomed to dealing with large datasets, yet they are fortunate in that the quality of their experimental data is very good. The onset of big data has led to an explosion of datasets with a far more complex structure — a development that requires new tools and a different mindset.

Thesis

Simple yet successful 

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p720

Mark Buchanan

doi:10.1038/nphys4228

Books and Arts

Music: Last night a DJ went to space 

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p721

doi:10.1038/nphys4226

News and Views

Gravitational-wave detection: Entanglement at work 

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pp723 - 724

Raffaele Flaminio

doi:10.1038/nphys4152

The Einstein–Podolsky–Rosen type of quantum entanglement can be used to improve the sensitivity of laser interferometer gravitational-wave detectors beyond the quantum limit.

Quantum simulation: Probing information scrambling 

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pp724 - 726

Monika Schleier-Smith

doi:10.1038/nphys4165

Quantum information encoded in one of many interacting particles quickly becomes scrambled. A set of tools for tracking this process is on its way.

Van der waals heterostructures: Exciting double bilayers 

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pp726 - 728

Koji Muraki

doi:10.1038/nphys4163

An excitonic Bose–Einstein condensate has so far been realized only in particular semiconductor heterostructure setups. Now, experiments show that such condensates can form in double graphene bilayers separated by hexagonal boron nitride.

Cell mechanics: The benefits of getting high 

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pp728 - 729

Klaus Kroy

doi:10.1038/nphys4128

Standard rheology tells us how a cell responds to deformation. But ramping up the frequency reveals more about its internal dynamics and morphology, mapping a route to improved drug treatments — and possible insight into the malignancy of cancers.

Letters

Testing universality of Efimov physics across broad and narrow Feshbach resonances 

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pp731 - 735

Jacob Johansen, B. J. DeSalvo, Krutik Patel & Cheng Chin

doi:10.1038/nphys4130

The emergence of Efimov states in ultracold atomic systems is expected to have a universal behaviour, but a new experimental study defies this expectation, reporting a clear deviation around a narrow Feshbach resonance.

Topological triplon modes and bound states in a Shastry–Sutherland magnet 

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pp736 - 741

P. A. McClarty, F. Krüger, T. Guidi, S. F. Parker, K. Refson, A. W. Parker, D. Prabhakaran & R. Coldea

doi:10.1038/nphys4117

A detailed experimental investigation on the spin excitations in SrCu₂(BO₃)₂ under an external magnetic confirms the existence of topological triplon modes in this experimental realization of the Shastry–Sutherland model.

Multidimensional entropy landscape of quantum criticality 

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pp742 - 745

K. Grube, S. Zaum, O. Stockert, Q. Si & H. v. Löhneysen

doi:10.1038/nphys4113

Thermal-expansion measurements of CeCu_6−xAu_xreveal the thermodynamic landscape of this material’s entropy, offering insights into the behaviour of quantum critical fluctuations as the system approaches its quantum critical point.

Quantum Hall drag of exciton condensate in graphene 

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pp746 - 750

Xiaomeng Liu, Kenji Watanabe, Takashi Taniguchi, Bertrand I. Halperin & Philip Kim

doi:10.1038/nphys4116

An electronic double layer, subjected to a high magnetic field, can form an exciton condensate: a Bose–Einstein condensate of Coulomb-bound electron–hole pairs. Now, exciton condensation is reported for a graphene/boron-nitride/graphene structure.

Excitonic superfluid phase in double bilayer graphene 

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pp751 - 755

J. I. A. Li, T. Taniguchi, K. Watanabe, J. Hone & C. R. Dean

doi:10.1038/nphys4140

Strongly interacting bosons have been predicted to display a transition into a superfluid ground state, similar to Bose–Einstein condensation. This effect is now observed in a double bilayer graphene structure, with excitons as the bosonic 

Tunnelling spectroscopy of Andreev states in graphene 

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pp756 - 760

Landry Bretheau, Joel I-Jan Wang, Riccardo Pisoni, Kenji Watanabe, Takashi Taniguchi & Pablo Jarillo-Herrero

doi:10.1038/nphys4110

Van der Waals heterostructures provide a tunable platform for probing the Andreev bound states responsible for proximity-induced superconductivity, helping to establish a connection between Andreev physics at finite energy and the Josephson effect.

Hotspot-mediated non-dissipative and ultrafast plasmon passage 

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pp761 - 765

Eva-Maria Roller, Lucas V. Besteiro, Claudia Pupp, Larousse Khosravi Khorashad, Alexander O. Govorov & Tim Liedl

doi:10.1038/nphys4120

Strong plasmonic hotspots can facilitate ultrafast energy transfer between metallic nanoparticles with almost no energy loss.

Attosecond chronoscopy of electron scattering in dielectric nanoparticles 

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pp766 - 770

L. Seiffert, Q. Liu, S. Zherebtsov, A. Trabattoni, P. Rupp, M. C. Castrovilli, M. Galli, F. Süßmann, K. Wintersperger, J. Stierle, G. Sansone, L. Poletto, F. Frassetto, I. Halfpap, V. Mondes, C. Graf, E. Rühl, F. Krausz, M. Nisoli, T. Fennel, F. Calegari & M. F. Kling

doi:10.1038/nphys4129

Attosecond streaking is used to study the dynamics of electron scattering in dielectric nanoparticles in real time. Revealing the mechanisms involved is the first step towards understanding electron scattering in more complex dielectrics.

High-frequency microrheology reveals cytoskeleton dynamics in living cells 

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pp771 - 775

Annafrancesca Rigato, Atsushi Miyagi, Simon Scheuring & Felix Rico

doi:10.1038/nphys4104

Microrheology of cells suggests that the dynamics of single filaments in the cytoskeleton dominate at high frequencies. This response can be used to detect differences between cell types and states — including benign and malignant cancer cells.

Articles

Proposal for gravitational-wave detection beyond the standard quantum limit through EPR entanglement 

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pp776 - 780

Yiqiu Ma, Haixing Miao, Belinda Heyun Pang, Matthew Evans, Chunnong Zhao, Jan Harms, Roman Schnabel & Yanbei Chen

doi:10.1038/nphys4118

Quantum metrology can enhance gravitational-wave detection through the use of squeezed states. A new proposal now suggests that with EPR entanglement one can do even better, reaching sensitivities beyond the standard quantum limit.

Measuring out-of-time-order correlations and multiple quantum spectra in a trapped-ion quantum magnet 

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pp781 - 786

Martin Gärttner, Justin G. Bohnet, Arghavan Safavi-Naini, Michael L. Wall, John J. Bollinger & Ana Maria Rey

doi:10.1038/nphys4119

Characterizing the correlations of quantum many-body systems is known to be hard, but there are ways around: for example, a new method for measuring out-of-time correlations demonstrated in a Penning trap quantum simulator with over 100 ions.

A dissipative quantum reservoir for microwave light using a mechanical oscillator 

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pp787 - 793

L. D. Tóth, N. R. Bernier, A. Nunnenkamp, A. K. Feofanov & T. J. Kippenberg

doi:10.1038/nphys4121

A microwave cavity optomechanics experiment investigates the interplay between the electromagnetic and mechanical modes and how their roles can be reversed in engineered dissipations.

Möbius Kondo insulators 

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pp794 - 798

Po-Yao Chang, Onur Erten & Piers Coleman

doi:10.1038/nphys4092

A family of topologically protected Kondo insulators, termed Möbius Kondo insulators, is predicted. A re-analysis of archival resistivity measurements of Ce₃Bi₄Pt₃ and CeNiSn suggests they may be good candidate members of this class.

Quasiparticle interference and strong electron–mode coupling in the quasi-one-dimensional bands of Sr₂RuO₄ 

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pp799 - 805

Zhenyu Wang, Daniel Walkup, Philip Derry, Thomas Scaffidi, Melinda Rak, Sean Vig, Anshul Kogar, Ilija Zeljkovic, Ali Husain, Luiz H. Santos, Yuxuan Wang, Andrea Damascelli, Yoshiteru Maeno, Peter Abbamonte, Eduardo Fradkin & Vidya Madhavan

doi:10.1038/nphys4107

The normal state of the ruthenate Sr₂RuO₄ is not that of a conventional metal but one with enhanced correlation effects, which may help to elucidate the origin of the unconventional superconductivity observed in this material.

Mottness at finite doping and charge instabilities in cuprates 

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pp806 - 811

S. Peli, S. Dal Conte, R. Comin, N. Nembrini, A. Ronchi, P. Abrami, F. Banfi, G. Ferrini, D. Brida, S. Lupi, M. Fabrizio, A. Damascelli, M. Capone, G. Cerullo & C. Giannetti

doi:10.1038/nphys4112

The electron dynamics of single-layer Bi₂Sr_2−xLa_xCuO_6+δ is studied as a function of doping, revealing the evolution of charge-transfer excitations from incoherent and localized (as in a Mott insulator) to coherent and delocalized (as in a conventional metal).

Mixed electrochemical–ferroelectric states in nanoscale ferroelectrics 

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pp812 - 818

Sang Mo Yang, Anna N. Morozovska, Rajeev Kumar, Eugene A. Eliseev, Ye Cao, Lucie Mazet, Nina Balke, Stephen Jesse, Rama K. Vasudevan, Catherine Dubourdieu & Sergei V. Kalinin

doi:10.1038/nphys4103

Nanoscale ferroelectricity is hard to characterize. Studies of BaTiO₃ thin films now reveal a close coupling between the ferroelectric and the surface electrochemical states — a notion important for future applications of ferroelectric nanomaterials.

Measure for Measure

The invention of dimension 

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p820

Steven T. Bramwell

doi:10.1038/nphys4229

Assigning dimensions to physical quantities is not just for practicality. Steven T. Bramwell reflects on the deeper physical connotations of it all.