Table of contents
April 2009, Volume 5 No 4 pp237-308
About the coverEditorials
Problem solved (probably) - p237
doi:10.1038/nphys1237
Research could progress as never before as scientists embrace the ever-growing possibilities for collaboration via the web.
Full Text - Problem solved (probably) | PDF (93 KB) - Problem solved (probably)
Science on hold - p237
doi:10.1038/nphys1254
It was all going so well — but then Obama's science appointments were blocked.
Commentary
Information awakening - pp238 - 240
Michael Nielsen
doi:10.1038/nphys1238
Online tools for collaboration and sharing information have changed the routine of scientists. But the revolution that will turn scientific information from a collection of files into an active system has just begun.
Full Text - Information awakening | PDF (156 KB) - Information awakening
Books and Arts
Grandfather of us all - pp243 - 244
Paul M. Grant reviews On Superconductivity and Superfluidity: A Scientific Autobiography by Vitaly L. Ginzburg
doi:10.1038/nphys1240
Full Text - Grandfather of us all | PDF (231 KB) - Grandfather of us all
Research Highlights
Research highlights - p245
doi:10.1038/nphys1246
Full Text - Research highlights | PDF (123 KB) - Research highlights
News and Views
Quantum information theory: The bits don't add up - pp247 - 248
Peter W. Shor
doi:10.1038/nphys1242
A counterexample to the 'additivity question', the most celebrated open problem in the mathematical theory of quantum information, casts doubt on the possibility of finding a simple expression for the information capacity of a quantum channel.
Full Text - Quantum information theoryThe bits don't add up | PDF (121 KB) - Quantum information theoryThe bits don't add up
Subject Categories: Information theory and computation | Quantum physics
See also: Letter by Hastings
Quantum physics: Schrödinger's cat is still alive - pp248 - 249
Jörg Wrachtrup
doi:10.1038/nphys1245
Strong coupling between a mechanical oscillator and the spin of an electron could enable cooling of the oscillator to its quantum ground state and measurement of the zero-point fluctuations.
Full Text - Quantum physicsSchrödinger's cat is still alive | PDF (134 KB) - Quantum physicsSchrödinger's cat is still alive
Subject Category: Quantum physics
Cosmology: Can the Universe survive a cosmic crunch? - p249
Alison Wright
doi:10.1038/nphys1235
Full Text - CosmologyCan the Universe survive a cosmic crunch? | PDF (104 KB) - CosmologyCan the Universe survive a cosmic crunch?
Subject Category: Astrophysics
Magnetism: Monopoles on the move - pp250 - 251
Roderich Moessner & Peter Schiffer
doi:10.1038/nphys1244
Magnetic materials provide a new context for observing magnetic monopoles. Numerical simulations now establish an experimentally measurable signature of their dynamics — one that has in fact already been seen in a spin-ice compound.
Full Text - MagnetismMonopoles on the move | PDF (484 KB) - MagnetismMonopoles on the move
Subject Categories: Materials physics | Particle physics
See also: Letter by Jaubert & Holdsworth
Biophysics: Nothing without water - p251
Andreas Trabesinger
doi:10.1038/nphys1236
Full Text - BiophysicsNothing without water | PDF (145 KB) - BiophysicsNothing without water
Subject Category: Biological physics
Quantum optics: Photon bunching two by two - pp252 - 253
Giuliano Scarcelli
doi:10.1038/nphys1241
Although the bunching of photons emitted from an incoherent source is well known, the nanosecond response times of conventional photon-counting detectors have prevented it from being observed directly. Using the ultrafast two-photon absorption characteristics of a semiconductor detector, such effects can now be studied at femtosecond timescales.
Full Text - Quantum opticsPhoton bunching two by two | PDF (124 KB) - Quantum opticsPhoton bunching two by two
Subject Categories: Optical physics | Electronics, photonics and device physics | Quantum physics
See also: Letter by Boitier et al.
Molecular physics: Molecules standing to attention - pp253 - 254
Jonathan G. Underwood
doi:10.1038/nphys1243
The combination of quantum-state selection and shaped femtosecond laser pulses provides a tool for creating samples of isolated molecules with precisely defined and controlled spatial orientation.
Full Text - Molecular physicsMolecules standing to attention | PDF (152 KB) - Molecular physicsMolecules standing to attention
Subject Categories: Atomic and molecular physics | Quantum physics
See also: Letter by Ghafur et al.
Letters
Superadditivity of communication capacity using entangled inputs - pp255 - 257
M. B. Hastings
doi:10.1038/nphys1224
The additivity conjecture of quantum information theory implies that entanglement cannot, even in principle, help to funnel more classical information through a quantum-communication channel. A counterexample shows that this conjecture is false.
First Paragraph - Superadditivity of communication capacity using entangled inputs | Full Text - Superadditivity of communication capacity using entangled inputs | PDF (439 KB) - Superadditivity of communication capacity using entangled inputs | Supplementary information
Subject Categories: Information theory and computation | Quantum physics
See also: News and Views by Shor
Signature of magnetic monopole and Dirac string dynamics in spin ice - pp258 - 261
L. D. C. Jaubert & P. C. W. Holdsworth
doi:10.1038/nphys1227
Magnetic monopoles have for a long time eluded detection by experiment. Theory now identifies a signature of monopole dynamics that is measurable experimentally, and that has already been seen in magnetic relaxation measurements in a spin-ice material.
First Paragraph - Signature of magnetic monopole and Dirac string dynamics in spin ice | Full Text - Signature of magnetic monopole and Dirac string dynamics in spin ice | PDF (641 KB) - Signature of magnetic monopole and Dirac string dynamics in spin ice
Subject Categories: Condensed-matter physics | Materials physics
See also: News and Views by Moessner & Schiffer
Ultrafast optical rotations of electron spins in quantum dots - pp262 - 266
A. Greilich, Sophia E. Economou, S. Spatzek, D. R. Yakovlev, D. Reuter, A. D. Wieck, T. L. Reinecke & M. Bayer
doi:10.1038/nphys1226
The spin state of electrons trapped in a quantum dot only lasts a few microseconds. Before this information is lost, it is useful to controllably rotate the spin as many times as possible. Laser pulses can now rotate electron spins in an ensemble of quantum dots in just a few picoseconds.
First Paragraph - Ultrafast optical rotations of electron spins in quantum dots | Full Text - Ultrafast optical rotations of electron spins in quantum dots | PDF (790 KB) - Ultrafast optical rotations of electron spins in quantum dots | Supplementary information
Subject Categories: Electronics, photonics and device physics | Optical physics
Measuring photon bunching at ultrashort timescale by two-photon absorption in semiconductors - pp267 - 270
F. Boitier, A. Godard, E. Rosencher & C. Fabre
doi:10.1038/nphys1218
Although the bunching of photons emitted from an incoherent source is well known, this has only ever been measured down to a temporal resolution of nanoseconds. This has now been improved by many orders of magnitude to the level of femtoseconds, with the elegantly simple use of a GaAs two-photon detector.
First Paragraph - Measuring photon bunching at ultrashort timescale by two-photon absorption in semiconductors | Full Text - Measuring photon bunching at ultrashort timescale by two-photon absorption in semiconductors | PDF (639 KB) - Measuring photon bunching at ultrashort timescale by two-photon absorption in semiconductors
Subject Categories: Optical physics | Electronics, photonics and device physics | Quantum physics
See also: News and Views by Scarcelli
Polychromatic dynamic localization in curved photonic lattices - pp271 - 275
Alexander Szameit, Ivan L. Garanovich, Matthias Heinrich, Andrey A. Sukhorukov, Felix Dreisow, Thomas Pertsch, Stefan Nolte, Andreas Tünnermann & Yuri S. Kivshar
doi:10.1038/nphys1221
The broadening of a wave-packet can be suppressed as it propagates through a periodic potential. The first-order effect of this so-called dynamic localization has been seen in many different systems. Higher-order effects are now seen for the first time in an optical pulse guided along curved photonic lattices.
First Paragraph - Polychromatic dynamic localization in curved photonic lattices | Full Text - Polychromatic dynamic localization in curved photonic lattices | PDF (1,163 KB) - Polychromatic dynamic localization in curved photonic lattices
Subject Category: Optical physics
Tightly trapped acoustic phonons in photonic crystal fibres as highly nonlinear artificial Raman oscillators - pp276 - 280
M. S. Kang, A. Nazarkin, A. Brenn & P. St. J. Russell
doi:10.1038/nphys1217
The scattering of laser light by acoustic phonons confined within a photonic crystal fibre reveals unexpected highly nonlinear acoustic modes that behave like the Raman-active modes of a molecule.
First Paragraph - Tightly trapped acoustic phonons in photonic crystal fibres as highly nonlinear artificial Raman oscillators | Full Text - Tightly trapped acoustic phonons in photonic crystal fibres as highly nonlinear artificial Raman oscillators | PDF (929 KB) - Tightly trapped acoustic phonons in photonic crystal fibres as highly nonlinear artificial Raman oscillators | Supplementary information
Subject Categories: Electronics, photonics and device physics | Optical physics
The quantum-optical Josephson interferometer - pp281 - 284
Dario Gerace, Hakan E. Türeci, Atac Imamoglu, Vittorio Giovannetti & Rosario Fazio
doi:10.1038/nphys1223
A proposed device—an optical analogue of the superconducting Josephson interferometer—might enable detailed studies of the role that dissipation has in strongly correlated quantum-optical systems.
First Paragraph - The quantum-optical Josephson interferometer | Full Text - The quantum-optical Josephson interferometer | PDF (758 KB) - The quantum-optical Josephson interferometer | Supplementary information
Subject Categories: Quantum physics | Optical physics
Observation of terahertz radiation coherently generated by acoustic waves - pp285 - 288
Michael R. Armstrong, Evan J. Reed, Ki-Yong Kim, James H. Glownia, William M. Howard, Edwin L. Piner & John C. Roberts
doi:10.1038/nphys1219
High-speed spectroscopy confirms predictions of the emission of terahertz radiation when a laser-induced acoustic wave passes across the interface between two piezoelectric materials.
First Paragraph - Observation of terahertz radiation coherently generated by acoustic waves | Full Text - Observation of terahertz radiation coherently generated by acoustic waves | PDF (829 KB) - Observation of terahertz radiation coherently generated by acoustic waves
Subject Category: Electronics, photonics and device physics
Impulsive orientation and alignment of quantum-state-selected NO molecules - pp289 - 293
Omair Ghafur, Arnaud Rouzée, Arjan Gijsbertsen, Wing Kiu Siu, Steven Stolte & Marc J. J. Vrakking
doi:10.1038/nphys1225
A technique that produces significant alignment of molecules in a beam should aid a wide range of experiments geared towards understanding and controlling molecular processes in the gas phase.
First Paragraph - Impulsive orientation and alignment of quantum-state-selected NO molecules | Full Text - Impulsive orientation and alignment of quantum-state-selected NO molecules | PDF (1,502 KB) - Impulsive orientation and alignment of quantum-state-selected NO molecules | Supplementary information
Subject Categories: Atomic and molecular physics | Quantum physics
See also: News and Views by Underwood
Effects of macromolecular crowding and DNA looping on gene regulation kinetics - pp294 - 297
Gene-Wei Li, Otto G. Berg & Johan Elf
doi:10.1038/nphys1222
Proteins seek out binding sites on DNA through diffusion and also by sliding along the strand. Although 'roadblocks'—other bound proteins on the DNA strand—slow things down, it seems that looping of the DNA aids the search process.
First Paragraph - Effects of macromolecular crowding and DNA looping on gene regulation kinetics | Full Text - Effects of macromolecular crowding and DNA looping on gene regulation kinetics | PDF (6,912 KB) - Effects of macromolecular crowding and DNA looping on gene regulation kinetics | Supplementary information
Subject Category: Biological physics
Articles
One-dimensional topologically protected modes in topological insulators with lattice dislocations - pp298 - 303
Ying Ran, Yi Zhang & Ashvin Vishwanath
doi:10.1038/nphys1220
Topological insulators are band insulators in which spin–orbit coupling takes the role of the applied magnetic field in the integer quantum Hall effect. Theory now predicts that dislocations in such systems can give rise to one-dimensional topologically protected states, resembling helical modes at the edge of a two-dimensional quantum spin Hall insulator.
Abstract - One-dimensional topologically protected modes in topological insulators with lattice dislocations | Full Text - One-dimensional topologically protected modes in topological insulators with lattice dislocations | PDF (2,124 KB) - One-dimensional topologically protected modes in topological insulators with lattice dislocations
Subject Categories: Condensed-matter physics | Information theory and computation
Electric displacement as the fundamental variable in electronic-structure calculations - pp304 - 308
Massimiliano Stengel, Nicola A. Spaldin & David Vanderbilt
doi:10.1038/nphys1185
The description of valence electrons in terms of non-local states that extend throughout a material presents problems for describing their contribution to ferroelectric polarization behaviour, which is inherently local. A new first-principles approach that treats electric displacement as a fundamental variable could provide a solution.
Abstract - Electric displacement as the fundamental variable in electronic-structure calculations | Full Text - Electric displacement as the fundamental variable in electronic-structure calculations | PDF (872 KB) - Electric displacement as the fundamental variable in electronic-structure calculations | Supplementary information
Subject Categories: Condensed-matter physics | Materials physics
