Table of contents



A very cool birthday p271


Superconductivity may have reached its centenary, but if anything it's a more active field of research today than ever. From materials dull or shiny, to the race for the Higgs boson, superconductivity remains relevant and exciting.

See also: Perspective by Basov & Chubukov



Manifesto for a higher Tc pp272 - 276

D. N. Basov & Andrey V. Chubukov


The term 'high-temperature superconductor' used to refer only to copper-based compounds — now, iron-based pnictides have entered the frame. The comparison of these two types of superconductor is revealing, and suggestive of what might be needed to achieve even higher transition temperatures.



Written in the stars p277

Mark Buchanan



Research Highlights

Our choice from the recent literature p278



News and Views

Turbulence: Thick puddle made thin pp279 - 280

Hamid Kellay


For turbulent flows, the energy transfer between large and small whirls depends on the dimension of the fluid. Imposing large-scale shear on a three-dimensional system can unexpectedly induce two-dimensional behaviour.

See also: Letter by Xia et al.

Optical lattices: More than a look pp280 - 281

J. V. Porto


A microscope that can both resolve individual atoms in an optical lattice and control their spin states should enable the exploration of many-body physics.

Nuclear astrophysics: Star bursts pinned down pp281 - 282

Philip Walker


One of the main uncertainties in the burn-up of X-ray bursts from neutron stars has been removed with the weighing of a key nucleus, 65As, at a new ion storage ring.

Microfluidics: Catching (and counting) a cold p282

David Gevaux


Copper-oxide superconductivity: The mystery and the mystique pp283 - 284

Zlatko Tesanovic


'Mottness' or a reconstructed Fermi surface? Nodes and arcs, or pockets? Both approaches to the pseudogap state of cuprate superconductors receive some support from specific heat data obtained up to 45 T. Can the two be reconciled?

See also: Article by Riggs et al.

Simon van der Meer: Stochastic success p284

Alison Wright


Dilute magnetic semiconductors: Hidden order revealed pp285 - 286

Michael E. Flatté


Dilute magnetic semiconductors such as gallium manganese arsenide could be key to the development of spintronics. But the relationship between electronic transport and magnetic properties has been hotly debated. Data indicating the preservation of the non-magnetic character of the host material provide startling new insight.

See also: Article by Ohya et al.



Photon shell game in three-resonator circuit quantum electrodynamics pp287 - 293

Matteo Mariantoni, H. Wang, Radoslaw C. Bialczak, M. Lenander, Erik Lucero, M. Neeley, A. D. O’Connell, D. Sank, M. Weides, J. Wenner, T. Yamamoto, Y. Yin, J. Zhao, John M. Martinis & A. N. Cleland


The ability to coherently switch a state between two systems is a key requirement for quantum information processing. Such control is now demonstrated by shifting the quantum state of a microwave photon between any one of three superconducting-circuit resonators: in analogy to the classic three cups and a ball game.

Subject terms: Electronics, photonics and device physics | Quantum physics

Magnetism and charge dynamics in iron pnictides pp294 - 297

Z. P. Yin, K. Haule & G. Kotliar


For the iron pnictide superconductors, a first-principles calculation of the magnetic state shows that correlations are important if we are to understand both the paramagnetic and magnetic phases. Moreover, the pnictides are fundamentally different from the cuprate superconductors in terms of spin and orbital physics.

Subject terms: Condensed-matter physics | Materials physics

Temporal correlations of superconductivity above the transition temperature in La2−xSrxCuO4 probed by terahertz spectroscopy pp298 - 302

L. S. Bilbro, R. Valdés Aguilar, G. Logvenov, O. Pelleg, I. Boz breveović & N. P. Armitage


Above the superconducting temperature for a given material, correlations between pairs of electrons are already present. Many experiments indicate that such correlations may exist up to 100 K above the transition. However, a temporal probe of the superconducting fluctuations suggests that correlations only exist within a narrow temperature range.

Subject terms: Condensed-matter physics | Materials physics

Direct observation of imprinted antiferromagnetic vortex states in CoO/Fe/Ag(001) discs pp303 - 306

J. Wu, D. Carlton, J. S. Park, Y. Meng, E. Arenholz, A. Doran, A. T. Young, A. Scholl, C. Hwang, H. W. Zhao, J. Bokor & Z. Q. Qiu


In thin magnetic films with confined geometry, the magnetization can adopt vortex-shaped arrangements. Such vortex states have been studied intensely in ferromagnetic films, but this paper reports the first direct observation of them in an antiferromagnetic system.

Subject terms: Condensed-matter physics | Nanotechnology

Electric-field-induced nuclear-spin flips mediated by enhanced spin–orbit coupling pp307 - 310

Toshiki Sugimoto & Katsuyuki Fukutani


Molecular hydrogen exists in two forms, which differ in the relative orientation of their nuclear spins. Interconversion between the two isomeric forms is extremely rare, unless there is an interaction breaking the symmetry between the two nuclei. Magnetic surfaces are known to act as such a catalyst, but this study finds that electric fields can also induce the spin flips necessary for the interconversion.

Subject term: Atomic and molecular physics

Noiseless non-reciprocity in a parametric active device pp311 - 315

Archana Kamal, John Clarke & M. H. Devoret


The use of microwaves to read and write information in superconducting qubits usually requires magnetic components that are difficult to integrate with chip-based circuits. A cascade of parametric amplifiers is now proposed instead, which could provide a more versatile and noise-free alternative.

Subject terms: Electronics, photonics and device physics | Optical physics

Universality beyond power laws and the average avalanche shape pp316 - 320

Stefanos Papanikolaou, Felipe Bohn, Rubem Luis Sommer, Gianfranco Durin, Stefano Zapperi & James P. Sethna


Power-law scaling of critical phenomena has been most powerful for predictions near a critical point. By averaging the noise emitted by avalanches of a given duration, however, universal scaling functions can extend the predictive power of scaling far from the critical point.

Subject terms: Statistical physics, thermodynamics and nonlinear dynamics | Condensed-matter physics

Upscale energy transfer in thick turbulent fluid layers pp321 - 324

H. Xia, D. Byrne, G. Falkovich & M. Shats


When a thick fluid, such as the Earth’s atmosphere, is driven simultaneously by a large-scale two-dimensional vortex and small-scale three-dimensional turbulence, experiments show that the large-scale flow dominates. Turbulence is thus confined to two dimensions, giving rise to an upscale energy cascade that powers the intermediate and large-scale flows.

Subject terms: Fluid dynamics | Statistical physics, thermodynamics and nonlinear dynamics

See also: News and Views by Kellay



Observation of ordered vortices with Andreev bound states in Ba0.6K0.4Fe2As2 pp325 - 331

Lei Shan, Yong-Lei Wang, Bing Shen, Bin Zeng, Yan Huang, Ang Li, Da Wang, Huan Yang, Cong Ren, Qiang-Hua Wang, Shuheng H. Pan & Hai-Hu Wen


The mystery of the missing bound states within a superconducting vortex in a pnictide superconductor has been solved. Not only are bound states present, they also provide information on the gap structure of Ba0.6K0.4Fe2As2.

Subject terms: Condensed-matter physics | Materials physics

Heat capacity through the magnetic-field-induced resistive transition in an underdoped high-temperature superconductor pp332 - 335

Scott C. Riggs, O. Vafek, J. B. Kemper, J. B. Betts, A. Migliori, F. F. Balakirev, W. N. Hardy, Ruixing Liang, D. A. Bonn & G. S. Boebinger


Quantum oscillations in a copper-oxide superconductor are observed using a thermodynamic probe. Surprisingly, these oscillations lie on a background signal that is consistent with d-wave superconductivity in the vortex state, in a magnetic field up to 45T.

Subject terms: Condensed-matter physics | Materials physics

See also: News and Views by Tesanovic

Random telegraph photosignals in a microwave-exposed two-dimensional electron system pp336 - 341

S. I. Dorozhkin, L. Pfeiffer, K. West, K. von Klitzing & J. H. Smet


Microwave radiation has a dramatic effect on the magneto-resistance of two-dimensional electron systems, even reducing it below zero. It is thought that this is the result of the formation of distinct current domains. Direct experimental evidence for these domains is now presented for the first time.

Subject terms: Materials physics | Optical physics

Nearly non-magnetic valence band of the ferromagnetic semiconductor GaMnAs pp342 - 347

Shinobu Ohya, Kenta Takata & Masaaki Tanaka


The magnetic properties of GaMnAs could be useful in the development of spintronic devices. Yet the precise origin of these properties has been hotly debated. Resonant-tunnelling spectra obtained from GaMnAs devices of superlative quality could finally resolve this issue.

Subject terms: Condensed-matter physics | Electronics, photonics and device physics | Materials physics

See also: News and Views by Flatté

Gate-dependent spin–orbit coupling in multielectron carbon nanotubes pp348 - 353

T. S. Jespersen, K. Grove-Rasmussen, J. Paaske, K. Muraki, T. Fujisawa, J. Nygård & K. Flensberg


The coupling of spin and orbital motion of electrons in carbon nanotubes has been demonstrated before, but a study now shows that the strength and sign of the spin–orbit coupling can be tuned by a gate voltage, and that, importantly for future applications, the effect survives in the presence of disorder.

Subject terms: Condensed-matter physics | Electronics, photonics and device physics

Piezoresistive heat engine and refrigerator pp354 - 359

P. G. Steeneken, K. Le Phan, M. J. Goossens, G. E. J. Koops, G. J. A. M. Brom, C. van der Avoort & J. T. M. van Beek


A micrometre-scale device that exploits the piezoresistive characteristics of silicon acts like an engine, converting heat into mechanical work in one mode of operation, and, in another, like a refrigerator, suppressing mechanical fluctuations.

Subject terms: Statistical physics, thermodynamics and nonlinear dynamics | Electronics, photonics and device physics

Observations and simulations of non-local acceleration of electrons in magnetotail magnetic reconnection events pp360 - 365

Maha Ashour-Abdalla, Mostafa El-Alaoui, Melvyn L. Goldstein, Meng Zhou, David Schriver, Robert Richard, Raymond Walker, Margaret G. Kivelson & Kyoung-Joo Hwang


Magnetic reconnection has long been implicated in the acceleration of electrons to relativistic speeds in the Earth’s magnetosphere. Satellite observations and simulations indicate it is just part of the story, the rest of which involves a second process known as betatron acceleration.

Subject terms: Plasma physics | Astrophysics