April 2012 Volume 8, Issue 4

Insight

Nature Physics Insight – Quantum Simulation

Editorial

Mismeasure for measure p249
doi:10.1038/nphys2295
In times of fiscal restraint, it is vital that every dollar, pound, yen, yuan and euro be put to good use. Lazy accounting, however, is no way to encourage excellence.
Full Text | PDF

Thesis

Grain of truth p251
Mark Buchanan
doi:10.1038/nphys2284
Full Text | PDF

Research Highlights

Strange goings-on | Frozen light switch | Optics for a better memory | Bacteria get around | Liquids in no man's land

News and Views

Editorial

Nature Physics Insight – Quantum Simulation
Quantum simulation p263
Andreas Trabesinger
doi:10.1038/nphys2258
Full Text | PDF

Commentary

Nature Physics Insight – Quantum Simulation
Goals and opportunities in quantum simulation pp264 - 266
J. Ignacio Cirac and Peter Zoller
doi:10.1038/nphys2275
The long-term promises of quantum simulators are far-reaching. The field, however, also needs clearly defined short-term goals.
Full Text | PDF

Reviews

Nature Physics Insight – Quantum Simulation
Quantum simulations with ultracold quantum gases pp267 - 276
Immanuel Bloch, Jean Dalibard and Sylvain Nascimbène
doi:10.1038/nphys2259
Experiments with ultracold quantum gases provide a platform for creating many-body systems that can be well controlled and whose parameters can be tuned over a wide range. These properties put these systems in an ideal position for simulating problems that are out of reach for classical computers. This review surveys key advances in this field and discusses the possibilities offered by this approach to quantum simulation.
Abstract | Full Text | PDF

Nature Physics Insight – Quantum Simulation
Quantum simulations with trapped ions pp277 - 284
R. Blatt and C. F. Roos
doi:10.1038/nphys2252
Experimental progress in controlling and manipulating trapped atomic ions has opened the door for a series of proof-of-principle quantum simulations. This article reviews these experiments, together with the methods and tools that have enabled them, and provides an outlook on future directions in the field.
Abstract | Full Text | PDF

Nature Physics Insight – Quantum Simulation
Photonic quantum simulators pp285 - 291
Alán Aspuru-Guzik and Philip Walther
doi:10.1038/nphys2253
Quantum optics has played an important role in the exploration of foundational issues in quantum mechanics, and in using quantum effects for information processing and communications purposes. Photonic quantum systems now also provide a valuable test bed for quantum simulations. This article surveys the first generation of such experiments, and discusses the prospects for tackling outstanding problems in physics, chemistry and biology.
Abstract | Full Text | PDF

Progress Article

Nature Physics Insight – Quantum Simulation
On-chip quantum simulation with superconducting circuits pp292 - 299
Andrew A. Houck, Hakan E. Türeci and Jens Koch
doi:10.1038/nphys2251
Lithographically fabricated micrometre-scale superconducting circuits exhibit behaviour analogues to natural quantum entities, such as atom, ions and photons. Large-scale arrays of such circuits hold the promise of providing a unique route to quantum simulation. Recent progress in technology and methodology are reviewed here, and prospects and challenges discussed.
Abstract | Full Text | PDF

Letters

Emergent electrodynamics of skyrmions in a chiral magnet pp301 - 304
T. Schulz, R. Ritz, A. Bauer, M. Halder, M. Wagner, C. Franz, C. Pfleiderer, K. Everschor, M. Garst and A. Rosch
doi:10.1038/nphys2231
An experiment demonstrates that the motion of so-called skyrmions—topologically quantized magnetic whirls—causes an emergent electric field that inherits the topological quantization of the skyrmions and is directly visible in the Hall effect.
First paragraph | Full Text | PDF

Spin-nematic squeezed vacuum in a quantum gas pp305 - 308
C. D. Hamley, C. S. Gerving, T. M. Hoang, E. M. Bookjans and M. S. Chapman
doi:10.1038/nphys2245
Squeezed states—which permit precision beyond the scope of Heisenberg's uncertainty relation—are well established for spin-1/2 particles. Now an elegant demonstration of squeezing in spin-1 condensates generalizes the criteria for squeezed states to higher spin dimensions.
First paragraph | Full Text | PDF
See also: News and Views by Lamacraft

Shallow pockets and very strong coupling superconductivity in FeSe_xTe_1-x  pp309 - 312
Y. Lubashevsky, E. Lahoud, K. Chashka, D. Podolsky and A. Kanigel
doi:10.1038/nphys2216
One proposed explanation of unconventional superconductivity involves describing it in terms of a crossover from a conventional superconducting state to a Bose-Einstein condensate state. Angle-resolved photoelectron measurements of an iron chalcogenide superconductor could provide evidence for such crossover behaviour.
First paragraph | Full Text | PDF

Nonlinear detection of spin currents in graphene with non-magnetic electrodes pp313 - 316
Ivan J. Vera-Marun, Vishal Ranjan and Bart J. van Wees
doi:10.1038/nphys2219
The degree to which an electrical current is spin polarized is usually determined by how easily it travels across an interface with a magnetic contact. By using nonlinear interactions between spin and charge in graphene, the polarization of spin currents can be measured without magnetic contacts.
First paragraph | Full Text | PDF

New chiral phases of superfluid ³He stabilized by anisotropic silica aerogel pp317 - 320
J. Pollanen, J. I. A. Li, C. A. Collett, W. J. Gannon, W. P. Halperin and J. A. Sauls
doi:10.1038/nphys2220
Liquid ³He in silica aerogel exhibits no trace of the chiral superfluid phase present in bulk ³He. Stretching the aerogel axially introduces an anisotropy that stabilizes the chiral phase, supporting a transition to a new disordered phase at low temperatures.
First paragraph | Full Text | PDF
See also: News and Views by Mineev

Large-scale electron acceleration by parallel electric fields during magnetic reconnection pp321 - 324
J. Egedal, W. Daughton and A. Le
doi:10.1038/nphys2249
Magnetic reconnection is a process by which the field lines of a magnetized plasma undergo dramatic realignment, releasing large amounts of energy. Large-scale simulations of reconnection events in the Earth's magnetosphere suggest that this process takes place over much greater distances than previously expected.
First paragraph | Full Text | PDF

Articles

Probing the relaxation towards equilibrium in an isolated strongly correlated one-dimensional Bose gas pp325 - 330
S. Trotzky, Y-A. Chen, A. Flesch, I. P. McCulloch, U. Schollwöck, J. Eisert and I. Bloch
doi:10.1038/nphys2232
How quantum many-body systems relax from an initial non-equilibrium state is one of the outstanding problems in quantum statistical physics. A study combining an experimental approach for monitoring the dynamics of strongly correlated cold atoms with theoretical analysis now provides quantitative insights into the problem.
Abstract | Full Text | PDF

Satellites and large doping and temperature dependence of electronic properties in hole-doped BaFe₂As₂  pp331 - 337
Philipp Werner, Michele Casula, Takashi Miyake, Ferdi Aryasetiawan, Andrew J. Millis and Silke Biermann
doi:10.1038/nphys2250
An approach to first-principles simulations that incorporates dynamically screened Coulomb interactions between iron d electrons enables the low-energy electronic structure and angle-resolved photoemission spectroscopy spectra of iron-based superconductors to be modelled with unprecedented accuracy.
Abstract | Full Text | PDF

Local probing of propagating acoustic waves in a gigahertz echo chamber pp338 - 343
Martin V. Gustafsson, Paulo V. Santos, Goran Johansson and Per Delsing
doi:10.1038/nphys2217
Mechanical oscillations of microscopic resonators have recently been observed in the quantum regime. This idea could soon be extended from localized vibrations to travelling waves thanks to a sensitive probe of so-called surface acoustic waves.
Abstract | Full Text | PDF
See also: News and Views by Clerk

Multistep redirection by cross-beam power transfer of ultrahigh-power lasers in a plasma pp344 - 349
J. D. Moody, P. Michel, L. Divol, R. L. Berger, E. Bond, D. K. Bradley, D. A. Callahan, E. L. Dewald, S. Dixit, M. J. Edwards, S. Glenn, A. Hamza, C. Haynam, D. E. Hinkel, N. Izumi, O. Jones, J. D. Kilkenny, R. K. Kirkwood, J. L. Kline, W. L. Kruer, G. A. Kyrala, O. L. Landen, S. LePape, J. D. Lindl, B. J. MacGowan, N. B. Meezan, A. Nikroo, M. D. Rosen, M. B. Schneider, D. J. Strozzi, L. J. Suter, C. A. Thomas, R. P. J. Town, K. Widmann, E. A. Williams, L. J. Atherton, S. H. Glenzer and E. I. Moses
doi:10.1038/nphys2239
A demonstration of the ability to control the flow of laser energy in a dense plasma by tuning the colour of multiple laser beams injected into it could be useful in the development of laser-driven fusion.
Abstract | Full Text | PDF

Corrigendum

Experimental demonstration of a universally valid error-disturbance uncertainty relation in spin measurements p349
Jacqueline Erhart, Stephan Sponar, Georg Sulyok, Gerald Badurek, Masanao Ozawa and Yuji Hasegawa
doi:10.1038/nphys2281
Full Text | PDF