Yuri S. Kivshar

Bio: Yuri S. Kivshar is an academic researcher from Australian National University. The author has contributed to research in topics: Metamaterial & Soliton. The author has an hindex of 126, co-authored 1845 publications receiving 79415 citations. Previous affiliations of Yuri S. Kivshar include Technische Universität Darmstadt & Los Alamos National Laboratory.

Stimulated Raman Scattering from Mie-Resonant Subwavelength Nanoparticles.

Abstract: Resonant dielectric structures have emerged recently as a new platform for subwavelength nonplasmonic photonics. It was suggested and demonstrated that magnetic and electric Mie resonances can enhance substantially many effects at the nanoscale including spontaneous Raman scattering. Here, we demonstrate stimulated Raman scattering (SRS) for isolated crystalline silicon (c-Si) nanoparticles and observe experimentally a transition from spontaneous to stimulated scattering manifested in a nonlinear growth of the signal intensity above a certain pump threshold. At the Mie resonance, the light gets confined into a low volume of the resonant mode with enhanced electromagnetic fields inside the c-Si nanoparticle due to its high refractive index, which leads to an overall strong SRS signal at low pump intensities. Our finding paves the way for the development of efficient Raman nanolasers for multifunctional photonic metadevices.

Suppression of transverse instabilities for vector solitons

Abstract: We analyze the transverse instability of two-component spatial solitons in a saturable nonlinear medium, in relation to recent experimental observations of spatial vector solitons in photorefractive media. We present the stability analysis for all three realizations: dark-bright, bright-bright, and dark-dark soliton pairs, and demonstrate that both the nonlinearity saturation and incoherent mode interaction can lead to a strong suppression of the soliton transverse instabilities.

Plasmonic nanoantennas for efficient control of polarization-entangled photon pairs

Abstract: We suggest a source of polarization-entangled photon pairs based on a cross-shaped plasmonic nanoantenna driven by a single quantum dot. The integration of the nanoantenna with a metal mirror overcomes the fundamental tradeoff between the spontaneous emission (SE) enhancement and the extraction efficiency typical of microcavity- and nanowire-based architectures. With a very high extraction efficiency of entangled photons ($\ensuremath{\approx}$$90%$) at $1.55$ $\ensuremath{\mu}$m and large SE enhancement ($\ensuremath{\approx}$90) over a broad 330-nm spectral range, the proposed design will pave the way toward reliable integrated sources of nonclassical light.

Generation and detection of matter-wave gap vortices in optical lattices

Abstract: We analyze numerically the process of dynamical generation of spatially localized vortices in Bose-Einstein condensates (BEC's) with repulsive atomic interactions confined by two-dimensional optical lattices Akin to bright solitons in a repulsive condensate, these nonlinear localized states exist only within the gaps of the matter-wave band-gap spectrum imposed by the periodicity of the lattice potential We discuss the complex structure of matter-wave phase singularities associated with different types of stationary gap vortices and suggest two different excitation methods In one method, the condensate is adiabatically driven to the edge of the Brillouin zone where a vortex phase is subsequently imprinted onto the condensate wave packet Alternatively, a vortex is created in a condensate confined in a harmonic trap and then is nonadiabatically released into the lattice potential We find that only the latter method leads to robust and reliable generation of vortices within the gap of the matter-wave band-gap spectrum Moreover, the nonadiabatic excitation can lead to the formation of broad gap vortices from the initial BEC wave packets with a large number of atoms These broad vortices are intimately connected to self-trapped nonlinear states of the BEC recently demonstrated in experiments with a one-dimensional optical lattice Our numerical simulations also confirm the feasibility of a homodyne interferometric detection of broad gap vortices

Stable nonlinear heavy-mass impurity modes

Abstract: We demonstrate that stable nonlinear localized modes can exist not only at a light-mass isotopic impurity, but also at a heavy-mass impurity, due to an interplay between discreteness and nonlinearity. This is in sharp contrast to the theory of linear lattice vibrations that an impurity mode is possible only at a light-mass defect. We determine the structure of the nonlinear impurity modes analytically using a four-particle approximation, and confirm the stability by direct numerical simulations.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。