In the last 30 days

• Open/close Visualization of spiral and scroll waves in simulated and experimental cardiac tissue

  E M Cherry and F H Fenton  2008 New J. Phys. 10 125016 Tag this article

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  The heart is a nonlinear biological system that can exhibit complex electrical dynamics, complete with period-doubling bifurcations and spiral and scroll waves that can lead to fibrillatory states that compromise the heart's ability to contract and pump blood efficiently. Despite the importance of understanding the range of cardiac dynamics, studying how spiral and scroll waves can initiate, evolve, and be terminated is challenging because of the complicated electrophysiology and anatomy of the heart. Nevertheless, over the last two decades advances in experimental techniques have improved access to experimental data and have made it possible to visualize the electrical state of the heart in more detail than ever before. During the same time, progress in mathematical modeling and computational techniques has facilitated using simulations as a tool for investigating cardiac dynamics. In this paper, we present data from experimental and simulated cardiac tissue and discuss visualization techniques that facilitate understanding of the behavior of electrical spiral and scroll waves in the context of the heart. The paper contains many interactive media, including movies and interactive two- and three-dimensional Java applets.

• Open/close Focus on Quantum Information and Many-Body Theory

  Jens Eisert and Martin B Plenio  2010 New J. Phys. 12 025001 Tag this article

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  Quantum many-body models describing natural systems or materials and physical systems assembled piece by piece in the laboratory for the purpose of realizing quantum information processing share an important feature: intricate correlations that originate from the coherent interaction between a large number of constituents. In recent years it has become manifest that the cross-fertilization between research devoted to quantum information science and to quantum many-body physics leads to new ideas, methods, tools, and insights in both fields. Issues of criticality, quantum phase transitions, quantum order and magnetism that play a role in one field find relations to the classical simulation of quantum systems, to error correction and fault tolerance thresholds, to channel capacities and to topological quantum computation, to name but a few. The structural similarities of typical problems in both fields and the potential for pooling of ideas then become manifest. Notably, methods and ideas from quantum information have provided fresh approaches to long-standing problems in strongly correlated systems in the condensed matter context, including both numerical methods and conceptual insights.

  Focus on quantum information and many-body theory Contents

  TENSOR NETWORKS

  Homogeneous multiscale entanglement renormalization ansatz tensor networks for quantum critical systems
  M Rizzi, S Montangero, P Silvi, V Giovannetti and Rosario Fazio

  Concatenated tensor network states
  R Hübener, V Nebendahl and W Dür

  Entanglement renormalization in free bosonic systems: real-space versus momentum-space renormalization group transforms
  G Evenbly and G Vidal

  Finite-size geometric entanglement from tensor network algorithms
  Qian-Qian Shi, Román Orús, John Ove Fjærestad and Huan-Qiang Zhou

  Characterizing symmetries in a projected entangled pair state
  D Pérez-García, M Sanz, C E González-Guillén, M M Wolf and J I Cirac

  Matrix product operator representations
  B Pirvu, V Murg, J I Cirac and F Verstraete

  SIMULATION AND DYNAMICS

  A quantum differentiation of k-SAT instances
  B Tamir and G Ortiz

  Classical Ising model test for quantum circuits
  Joseph Geraci and Daniel A Lidar

  Exact matrix product solutions in the Heisenberg picture of an open quantum spin chain
  S R Clark, J Prior, M J Hartmann, D Jaksch and M B Plenio

  Exact solution of Markovian master equations for quadratic Fermi systems: thermal baths, open XY spin chains and non-equilibrium phase transition
  Tomaž Prosen and Bojan Žunkovič

  Quantum kinetic Ising models
  R Augusiak, F M Cucchietti, F Haake and M Lewenstein

  ENTANGLEMENT AND SPECTRAL PROPERTIES

  Correlation density matrices for one-dimensional quantum chains based on the density matrix renormalization group
  W Münder, A Weichselbaum, A Holzner, Jan von Delft and C L Henley

  The invariant-comb approach and its relation to the balancedness of multipartite entangled states
  Andreas Osterloh and Jens Siewert

  Entanglement scaling of fractional quantum Hall states through geometric deformations
  Andreas M Läuchli, Emil J Bergholtz and Masudul Haque

  Entanglement versus gap for one-dimensional spin systems
  Daniel Gottesman and M B Hastings

  Entanglement spectra of critical and near-critical systems in one dimension
  F Pollmann and J E Moore

  Macroscopic bound entanglement in thermal graph states
  D Cavalcanti, L Aolita, A Ferraro, A García-Saez and A Acín

  Entanglement at the quantum phase transition in a harmonic lattice
  Elisabeth Rieper, Janet Anders and Vlatko Vedral

  Multipartite entanglement and frustration
  P Facchi, G Florio, U Marzolino, G Parisi and S Pascazio

  Entropic uncertainty relations—a survey
  Stephanie Wehner and Andreas Winter

  Entanglement in a spin system with inverse square statistical interaction
  D Giuliano, A Sindona, G Falcone, F Plastina and L Amico

  APPLICATIONS

  Time-dependent currents of one-dimensional bosons in an optical lattice
  J Schachenmayer, G Pupillo and A J Daley

  Implementing quantum gates using the ferromagnetic spin-J XXZ chain with kink boundary conditions
  Tom Michoel, Jaideep Mulherkar and Bruno Nachtergaele

  Long-distance entanglement in many-body atomic and optical systems
  Salvatore M Giampaolo and Fabrizio Illuminati

  QUANTUM MEMORIES AND TOPOLOGICAL ORDER

  Thermodynamic stability criteria for a quantum memory based on stabilizer and subsystem codes
  Stefano Chesi, Daniel Loss, Sergey Bravyi and Barbara M Terhal

  Topological color codes and two-body quantum lattice Hamiltonians
  M Kargarian, H Bombin and M A Martin-Delgado

  RENORMALIZATION

  Local renormalization method for random systems
  O Gittsovich, R Hübener, E Rico and H J Briegel

• Open/close Focus on Plasma Medicine

  G E Morfill et al  2009 New J. Phys. 11 115011 Tag this article

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  'Plasma Healthcare' is an emerging interdisciplinary research topic of rapidly growing importance, exploring considerable opportunities at the interface of plasma physics, chemistry and engineering with life sciences. Some of the scientific discoveries reported so far have already demonstrated clear benefits for healthcare in areas of medicine, food safety, environmental hygiene, and cosmetics. Examples include ongoing studies of prion inactivation, chronic wound treatment and plasma-mediated cancer therapy. Current research ranges from basic physical processes, plasma chemical design, to the interaction of plasmas with (i) eukaryotic (mammalian) cells; (ii) prokaryotic (bacteria) cells, viruses, spores and fungi; (iii) DNA, lipids, proteins and cell membranes; and (iv) living human, animal and plant tissues in the presence of biofluids. Of diverse interests in this new field is the need for hospital disinfection, in particular with respect to the alarming increase in bacterial resistance to antibiotics, the concomitant needs in private practices, nursing homes etc, the applications in personal hygiene—and the enticing possibility to 'design' plasmas as possible pharmaceutical products, employing ionic as well as molecular agents for medical treatment. The 'delivery' of the reactive plasma agents occurs at the gaseous level, which means that there is no need for a carrier medium and access to the treatment surface is optimal. This focus issue provides a close look at the current state of the art in Plasma Medicine with a number of forefront research articles as well as an introductory review.

  Focus on Plasma Medicine Contents

  Application of epifluorescence scanning for monitoring the efficacy of protein removal by RF gas-plasma decontamination
  Helen C Baxter, Patricia R Richardson, Gaynor A Campbell, Valeri I Kovalev, Robert Maier, James S Barton, Anita C Jones, Greg DeLarge, Mark Casey and Robert L Baxter

  Inactivation factors of spore-forming bacteria using low-pressure microwave plasmas in an N ₂ and O ₂ gas mixture
  M K Singh, A Ogino and M Nagatsu

  Degradation of adhesion molecules of G361 melanoma cells by a non-thermal atmospheric pressure microplasma
  H J Lee, C H Shon, Y S Kim, S Kim, G C Kim and M G Kong

  The acidification of lipid film surfaces by non-thermal DBD at atmospheric pressure in air
  A Helmke, D Hoffmeister, N Mertens, S Emmert, J Schuette and W Vioel

  Reduction and degradation of amyloid aggregates by a pulsed radio-frequency cold atmospheric plasma jet
  D L Bayliss, J L Walsh, G Shama, F Iza and M G Kong

  The effect of low-temperature plasma on bacteria as observed by repeated AFM imaging
  René Pompl, Ferdinand Jamitzky, Tetsuji Shimizu, Bernd Steffes, Wolfram Bunk, Hans-Ulrich Schmidt, Matthias Georgi, Katrin Ramrath, Wilhelm Stolz, Robert W Stark, Takuya Urayama, Shuitsu Fujii and Gregor Eugen Morfill

  Removal and sterilization of biofilms and planktonic bacteria by microwave-induced argon plasma at atmospheric pressure
  Mi Hee Lee, Bong Joo Park, Soo Chang Jin, Dohyun Kim, Inho Han, Jungsung Kim, Soon O Hyun, Kie-Hyung Chung and Jong-Chul Park

  Cell permeabilization using a non-thermal plasma
  M Leduc, D Guay, R L Leask and S Coulombe

  Physical and biological mechanisms of direct plasma interaction with living tissue
  Danil Dobrynin, Gregory Fridman, Gary Friedman and Alexander Fridman

  Nosocomial infections-a new approach towards preventive medicine using plasmas
  G E Morfill, T Shimizu, B Steffes and H-U Schmidt

  Generation and transport mechanisms of chemical species by a post-discharge flow for inactivation of bacteria
  Takehiko Sato, Shiroh Ochiai and Takuya Urayama

  Low pressure plasma discharges for the sterilization and decontamination of surfaces
  F Rossi, O Kylián, H Rauscher, M Hasiwa and D Gilliland

  Contribution of a portable air plasma torch to rapid blood coagulation as a method of preventing bleeding
  S P Kuo, O Tarasenko, J Chang, S Popovic, C Y Chen, H W Fan, A Scott, M Lahiani, P Alusta, J D Drake and M Nikolic

  A two-dimensional cold atmospheric plasma jet array for uniform treatment of large-area surfaces for plasma medicine
  QY Nie, Z Cao, C S Ren, D Z Wang and M G Kong

  A novel plasma source for sterilization of living tissues
  E Martines, M Zuin, R Cavazzana, E Gazza, G Serianni, S Spagnolo, M Spolaore, A Leonardi, V Deligianni, P Brun, M Aragona, I Castagliuolo and P Brun

  Designing plasmas for chronic wound disinfection
  T Nosenko, T Shimizu and G E Morfill

  Plasma medicine: an introductory review
  M G Kong, G Kroesen, G Morfill, T Nosenko, T Shimizu, J van Dijk and J L Zimmermann

• Open/close Transport in nanofluidic systems: a review of theory and applications

  W Sparreboom et al  2010 New J. Phys. 12 015004 Tag this article

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  In this paper transport through nanochannels is assessed, both of liquids and of dissolved molecules or ions. First, we review principles of transport at the nanoscale, which will involve the identification of important length scales where transitions in behavior occur. We also present several important consequences that a high surface-to-volume ratio has for transport. We review liquid slip, chemical equilibria between solution and wall molecules, molecular adsorption to the channel walls and wall surface roughness. We also identify recent developments and trends in the field of nanofluidics, mention key differences with microfluidic transport and review applications. Novel opportunities are emphasized, made possible by the unique behavior of liquids at the nanoscale.

• Open/close Efficient production of polar molecular Bose–Einstein condensates via an all-optical R-type atom–molecule adiabatic passage

  Jing Qian et al  2010 New J. Phys. 12 033002 Tag this article

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  We propose a scheme of 'R-type' photoassociative adiabatic passage (PAP) to create polar molecular condensates from two different species of ultracold atoms. Due to the presence of a quasi-coherent population trapping state in the scheme, it is possible to associate atoms into molecules with a low-power photoassociation (PA) laser. One remarkable advantage of our scheme is that a tunable atom–molecule coupling strength can be achieved by using a time-dependent PA field, which exhibits larger flexibility than using a tunable magnetic field. In addition, our results show that the PA intensity required in the 'R-type' PAP could be greatly reduced compared to that in a conventional 'Λ-type' one.

• Open/close Lattice coupling and Franck–Condon effects in K-edge resonant inelastic x-ray scattering

  J N Hancock et al  2010 New J. Phys. 12 033001 Tag this article

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  In this paper, we discuss our recent Cu K-edge resonant inelastic x-ray scattering (RIXS) results for CuB ₂O ₄, a model system consisting of electronically isolated CuO ₄ plaquettes, which exhibits anomalies in the incident photon energy dependence that are not captured by electron-only models. We show that these anomalous features can be qualitatively described by extending the electron-only considerations to include the lattice degrees of freedom. Our findings have important general implications for the interpretation of K-edge RIXS results for electronically higher-dimensional transition metal oxides.

• Open/close FOCUS ON PLASMONICS

  Sergey Bozhevolnyi and Francisco García-Vidal  2008 New J. Phys. 10 105001 Tag this article

  Article References

  Plasmonics is an emerging field in optics dealing with the so-called surface plasmons whose extraordinary properties are being both analyzed from a fundamental point of view and exploited for numerous technological applications. Surface plasmons associated with surface electron density oscillations decorating metal–dielectric interfaces were discovered by Rufus Ritchie in the 1950s. Since the seventies, the subwavelength confinement of electromagnetic fields as well as their enhancement inherent to the surface plasmon excitation has been widely used for spectroscopic purposes. Recent advances in nano-fabrication, characterization and modelling techniques have allowed unique properties of these surface electromagnetic modes to be explored with respect to subwavelength field localization and waveguiding, opening the path to truly nanoscale plasmonic optical devices. This area of investigation also has interesting links with research on photonic band gap materials and the field of optical metamaterials. Nowadays, plasmonics can be seen as a mature interdisciplinary area of research in which scientists coming from different backgrounds (chemistry, physics, optics and engineering) strive to discover and exploit new and exciting phenomena associated with surface plasmons. The already made and forthcoming discoveries will have impacts in many fields of science and technology, including not only photonics and materials science but also computation, biology and medicine, among others.

  This focus issue of New Journal of Physics is intended to cover all the aforementioned capabilities of surface plasmons by presenting a current overview of state-of-the-art advances achieved by the leading groups in this field of research.

   

  Focus on Plasmonics Contents

  Controlled modification of erbium lifetime by near-field coupling to metallic films
  Nanfang Yu, Alexey Belyanin, Jiming Bao and Federico Capasso

  Directional coupling between dielectric and long-range plasmon waveguides
  Aloyse Degiron, Sang-Yeon Cho, Talmage Tyler, Nan Marie Jokerst and David R Smith

  Nanoantenna array-induced fluorescence enhancement and reduced lifetimes
  Reuben M Bakker, Vladimir P Drachev, Zhengtong Liu, Hsiao-Kuan Yuan, Rasmus H Pedersen, Alexandra Boltasseva, Jiji Chen, Joseph Irudayaraj, Alexander V Kildishev and Vladimir M Shalaev

  Confinement and propagation characteristics of subwavelength plasmonic modes
  R F Oulton, G Bartal, D F P Pile and X Zhang

  Theory on the scattering of light and surface plasmon polaritons by arrays of holes and dimples in a metal film
  F de León-Pérez, G Brucoli, F J García-Vidal and L Martín-Moreno

  Shaping and manipulation of light fields with bottom-up plasmonic structures
  C Girard, E Dujardin, G Baffou and R Quidant

  Gold nanorods and nanospheroids for enhancing spontaneous emission
  A Mohammadi, V Sandoghdar and M Agio

  Generation of surface plasmons at single subwavelength slits: from slit to ridge plasmon
  J-Y Laluet, A Drezet, C Genet and T W Ebbesen

  Mode mapping of plasmonic stars using TPL microscopy
  P Ghenuche, S Cherukulappurath and R Quidant

  Controlling optical transmission through magneto-plasmonic crystals with an external magnetic field
  G A Wurtz, W Hendren, R Pollard, R Atkinson, L Le Guyader, A Kirilyuk, Th Rasing, I I Smolyaninov and A V Zayats

  Nanoplasmonic renormalization and enhancement of Coulomb interactions
  M Durach, A Rusina, V I Klimov and M I Stockman

  Bulk and surface sensitivities of surface plasmon waveguides
  Pierre Berini

  Mapping plasmons in nanoantennas via cathodoluminescence
  R Gómez-Medina, N Yamamoto, M Nakano and F J García de Abajo

  Theoretical analysis of gold nano-strip gap plasmon resonators
  T Søndergaard, J Jung, S I Bozhevolnyi and G Della Valle

  Surface plasmon polariton-mediated enhancement of the emission of dye molecules on metallic gratings
  J Gómez Rivas, G Vecchi and V Giannini

  Nanoshells to nanoeggs to nanocups: optical properties of reduced symmetry core–shell nanoparticles beyond the quasistatic limit
  Mark W Knight and Naomi J Halas

  Single emitters coupled to plasmonic nano-antennas: angular emission and collection efficiency
  T H Taminiau, F D Stefani and N F van Hulst

  Green's tensor calculations of plasmon resonances of single holes and hole pairs in thin gold films
  Joan Alegret, Peter Johansson and Mikael Käll

  Optical and terahertz near-field studies of surface plasmons in subwavelength metallic slits
  K J Ahn, K G Lee, H W Kihm, M A Seo, A J L Adam, P C M Planken and D S Kim

  Fluorescence enhancement through modified dye molecule absorption associated with the localized surface plasmon resonances of metallic dimers
  George Zoriniants and William L Barnes

• Open/close Rigid sphere transport through a colloidal gas–liquid interface

  J W J de Folter et al  2010 New J. Phys. 12 023013 Tag this article

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  In this paper we report on the gravity-driven transport of rigid spheres of various sizes through the fluid–fluid interface of a demixed colloid–polymer mixture. Three consecutive stages can be distinguished: (i) the sphere approaches the interface by sedimenting through the polymer-rich phase, (ii) it is subsequently transported to the colloid-rich phase and (iii) it moves away from the interface. The spheres are covered by a thin wetting film of the colloid-rich phase, to which they are eventually transported. The ultralow interfacial tension in these phase-separating mixtures results in very small capillary forces so that the process takes place in the low Reynolds regime. Moreover, it enables the investigation of the role of capillary waves in the process. Depending on the Bond number, the ratio between gravitational force and capillary force acting on the sphere, different transport configurations are observed. At low Bond numbers, the drainage transport configuration, with a dominant capillary force, is encountered. At high Bond numbers, spheres are transported through the tailing configuration, with a dominant gravitational force. By varying the sphere diameter, we observe both transport configurations as well as a crossover regime in a single experimental system.

• Open/close How metal films de-wet substrates—identifying the kinetic pathways and energetic driving forces

  Kevin F McCarty et al  2009 New J. Phys. 11 043001 Tag this article

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  We study how single-crystal chromium films of uniform thickness on W(110) substrates are converted to arrays of three-dimensional (3D) Cr islands during annealing. We use low-energy electron microscopy (LEEM) to directly observe a kinetic pathway that produces trenches that expose the wetting layer. Adjacent film steps move simultaneously uphill and downhill relative to the staircase of atomic steps on the substrate. This step motion thickens the film regions where steps advance. Where film steps retract, the film thins, eventually exposing the stable wetting layer. Since our analysis shows that thick Cr films have a lattice constant close to bulk Cr, we propose that surface and interface stress provide a possible driving force for the observed morphological instability. Atomistic simulations and analytic elastic models show that surface and interface stress can cause a dependence of film energy on thickness that leads to an instability to simultaneous thinning and thickening. We observe that de-wetting is also initiated at bunches of substrate steps in two other systems, Ag/W(110) and Ag/Ru(0001). We additionally describe how Cr films are converted into patterns of unidirectional stripes as the trenches that expose the wetting layer lengthen along the W[001] direction. Finally, we observe how 3D Cr islands form directly during film growth at elevated temperature. The Cr mesas (wedges) form as Cr film steps advance down the staircase of substrate steps, another example of the critical role that substrate steps play in 3D island formation.

• Open/close Plasma medicine: an introductory review

  M G Kong et al  2009 New J. Phys. 11 115012 Tag this article

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  This introductory review on plasma health care is intended to provide the interested reader with a summary of the current status of this emerging field, its scope, and its broad interdisciplinary approach, ranging from plasma physics, chemistry and technology, to microbiology, biochemistry, biophysics, medicine and hygiene. Apart from the basic plasma processes and the restrictions and requirements set by international health standards, the review focuses on plasma interaction with prokaryotic cells (bacteria), eukaryotic cells (mammalian cells), cell membranes, DNA etc. In so doing, some of the unfamiliar terminology—an unavoidable by-product of interdisciplinary research—is covered and explained. Plasma health care may provide a fast and efficient new path for effective hospital (and other public buildings) hygiene—helping to prevent and contain diseases that are continuously gaining ground as resistance of pathogens to antibiotics grows. The delivery of medically active 'substances' at the molecular or ionic level is another exciting topic of research through effects on cell walls (permeabilization), cell excitation (paracrine action) and the introduction of reactive species into cell cytoplasm. Electric fields, charging of surfaces, current flows etc can also affect tissue in a controlled way. The field is young and hopes are high. It is fitting to cover the beginnings in New Journal of Physics, since it is the physics (and non-equilibrium chemistry) of room temperature atmospheric pressure plasmas that have made this development of plasma health care possible.