Volume 13 Issue 8, August 2017

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.

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

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.

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.

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.

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.

Thermal-expansion measurements of CeCu_6−xAu_x reveal 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.

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.

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 particles.

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.

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

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.

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.

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.

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

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.

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.

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).

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.

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