December 2013 Volume 9, Issue 12

Editorials

Hot stuff   p751
doi:10.1038/nphys2827
Every scientist has an interest in their own citations, but regularly updated maps of citations across all of science are tracking what's hot and what's not.

You know who   p751
doi:10.1038/nphys2828
Remember, remember 23 November: it's 'The Day of the Doctor'.

Thesis

Time to think   p752
Mark Buchanan
doi:10.1038/nphys2830

Research Highlights

Material mix | Bottoms up | Non-friction | Photons on the edge | Minimal contact

News and Views

Correction

Correction   p760
doi:10.1038/nphys2823

Letters

Universal quantum oscillations in the underdoped cuprate superconductors   pp761 - 764
Neven Barišić, Sven Badoux, Mun K. Chan, Chelsey Dorow, Wojciech Tabis et al.
doi:10.1038/nphys2792
Every metal has an underlying Fermi surface that gives rise to quantum oscillations. So far, quantum oscillation measurements in the superconductor YBCO have been inconclusive owing to the structural complexities of the material. Quantum oscillations in a Hg-based cuprate—with a much simpler structure—help to establish the origin and universality of the oscillations.

See also: News and Views by Norman |

Protection of excited spin states by a superconducting energy gap   pp765 - 768
B. W. Heinrich, L. Braun, J. I. Pascual and K. J. Franke
doi:10.1038/nphys2794
When a paramagnetic molecule is placed on a superconducting surface the lifetime of its spin excitations increases dramatically. This effect, caused by the depletion of the electronic states within the energy gap at the Fermi level, could find application in coherent spin manipulation.

See also: News and Views by Hirjibehedin |

Direct observation of effective ferromagnetic domains of cold atoms in a shaken optical lattice   pp769 - 774
Colin V. Parker, Li-Chung Ha and Cheng Chin
doi:10.1038/nphys2789
Ultracold atoms in optical lattices are used to study various phenomena in condensed-matter physics, such as magnetism. A lattice-shaking technique can induce a strong effective spin-interaction, leading to the formation of ferromagnetic domains.

The superfluid glass phase of ³He-A   pp775 - 779
J. I. A. Li, J. Pollanen, A. M. Zimmerman, C. A. Collett, W. J. Gannon et al.
doi:10.1038/nphys2806
Confined within a porous aerogel, superfluid ³He loses its long-range order owing to random microscopic disorder, and becomes a glassy superfluid. Intriguingly, this effect can be switched off and the superfluidity restored.

Optical diametric drive acceleration through action-reaction symmetry breaking   pp780 - 784
Martin Wimmer, Alois Regensburger, Christoph Bersch, Mohammad-Ali Miri, Sascha Batz et al.
doi:10.1038/nphys2777
An action generates an equal and opposite reaction. If it were possible, however, for one of the two bodies to have negative mass, they would accelerate each other. A situation analogous to this is now realized in an optical system. Solitons moving in an optical mesh lattice exhibit either an effective positive or negative mass, thus enabling observation of self-acceleration.

See also: News and Views by Philbin |

Fast optical modulation of the fluorescence from a single nitrogen-vacancy centre   pp785 - 789
Michael Geiselmann, Renaud Marty, F. Javier García de Abajo and Romain Quidant
doi:10.1038/nphys2770
The intensity of optically-pumped fluorescence generated from a single atomic defect in diamond can be reduced by 80% in just 100 ns by applying infrared laser light. This result demonstrates the possibility of using these so-called nitrogen-vacancy centres to create optical switches that operate at room temperature.

Fourier-transform inelastic X-ray scattering from time- and momentum-dependent phonon-phonon correlations   pp790 - 794
M. Trigo, M. Fuchs, J. Chen, M. P. Jiang, M. Cammarata et al.
doi:10.1038/nphys2788
Femtosecond pulses from X-ray free-electron lasers offer a powerful method for observing the coherent dynamic of phonons in crystalline materials, it is now shown. This time-resolved spectroscopic tool could provide insight into low-energy collective excitations in solids and how they interact at a microscopic level to determine the material's macroscopic properties.

See also: News and Views by Abbamonte |

Articles

Direct measurement of the Zak phase in topological Bloch bands   pp795 - 800
Marcos Atala, Monika Aidelsburger, Julio T. Barreiro, Dmitry Abanin, Takuya Kitagawa et al.
doi:10.1038/nphys2790
In the band theory of solids, the topological properties of Bloch bands are characterized by geometric phases. For cold atoms moving in a one-dimensional optical potential the geometric phase can be measured directly using Bloch oscillations and Ramsey interferometry.

Spintronic magnetic anisotropy   pp801 - 805
Maciej Misiorny, Michael Hell and Maarten R. Wegewijs
doi:10.1038/nphys2766
Superparamagnetism (preferential alignment of spins along an easy axis) is a useful effect for spintronic applications as it prevents spin reversal. It is now shown that high-spin quantum dots can become magnetically anisotropic when coupled to nearby ferromagnets — 'artificial' superparamagnets.

Thermal nonlinearities in a nanomechanical oscillator   pp806 - 810
Jan Gieseler, Lukas Novotny and Romain Quidant
doi:10.1038/nphys2798
A room-temperature motion sensor with record sensitivity is created using a levitating silica nanoparticle. Feedback cooling to reduce the noise arising from Brownian motion enables a detector that is perhaps even sensitive enough to detect non-Newtonian gravity-like forces.

Quasiperiodic acceleration of electrons by a plasmoid-driven shock in the solar atmosphere   pp811 - 816
Eoin P. Carley, David M. Long, Jason P. Byrne, Pietro Zucca, D. Shaun Bloomfield et al.
doi:10.1038/nphys2767
A combination of measurements from the Solar Dynamics Observatory and radiospectroscopy data from the Nancay Radioheliograph now details the mechanism that connects coronal mass ejections from the sun and the acceleration of particles to relativistic speeds. A spatial and temporal correlation between a coronal 'bright front' and radio emissions associated with electron acceleration demonstrates the fundamental relationship between the two.

See also: News and Views by Cliver |

A long-pulse high-confinement plasma regime in the Experimental Advanced Superconducting Tokamak   pp817 - 821
J. Li, H. Y. Guo, B. N. Wan, X. Z. Gong, Y. F. Liang et al.
doi:10.1038/nphys2795
A high-confinement plasma that is potentially useful for controlled fusion has now been sustained for over 30 s. The Experimental Advanced Superconducting Tokamak in Hefei, China, achieved this record pulse length by first confining the plasma using lithium-treated vessel walls, and then maintaining it with a so-called lower hybrid current drive.

See also: News and Views by Morris |