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 …

I and i

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。

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

Conventional optical components rely on gradual phase shifts accumulated during light propagation to shape light beams. New degrees of freedom are attained by introducing abrupt phase changes over the scale of the wavelength. A two-dimensional array of optical resonators with spatially varying phase response and subwavelength separation can imprint such phase discontinuities on propagating light as it traverses the interface between two media. Anomalous reflection and refraction phenomena are observed in this regime in optically thin arrays of metallic antennas on silicon with a linear phase variation along the interface, which are in excellent agreement with generalized laws derived from Fermat’s principle. Phase discontinuities provide great flexibility in the design of light beams, as illustrated by the generation of optical vortices through use of planar designer metallic interfaces.

http://www.zenogaburro.it/papers/LightPropagation.pdf

Light Propagation with Phase Discontinuities: Generalized Laws of Reflection and Refraction

Bose-Einstein condensation (BEC) has been observed in a dilute gas of sodium atoms. A Bose-Einstein condensate consists of a macroscopic population of the ground state of the system, and is a coherent state of matter. In an ideal gas, this phase transition is purely quantum-statistical. The study of BEC in weakly interacting systems which can be controlled and observed with precision holds the promise of revealing new macroscopic quantum phenomena that can be understood from first principles.

Bose-Einstein condensation in a gas of sodium atoms

Plasmons in strongly coupled metallic nanostructures.

We review the theoretical and experimental status of intense laser alignment---a field at the interface between intense laser physics and chemical dynamics with potential applications ranging from high harmonic generation and nanoscale processing to stereodynamics and control of chemical reactions After placing the intense laser approach in context with other alignment techniques, we proceed with a discussion of the physics underlying this technique and a description of methods of observing it in the laboratory The roles played by the laser frequency, the pulse duration, and the system temperature are illustrated numerically and experimentally Alignment is extended to three-dimensional orientational control, a method of hindering the rotation about all three axes of polyatomic molecules We conclude with a discussion of potential applications of intense laser alignment

/pdf/colloquium-aligning-molecules-with-strong-laser-pulses-73jo8z061c.pdf

Colloquium: Aligning molecules with strong laser pulses

The rate of nonlinear ionization is strongly enhanced as a molecule is stretched beyond its equilibrium internuclear separation, reaching a peak rate that is many orders of magnitude greater than that at either small or large distances. The enhancement results from nonadiabatic electron localization near the nuclei and its presence is insensitive to the laser frequency and intensity. Most intense-field dissociative ionization experiments are influenced by this effect.

Role of electron localization in intense-field molecular ionization.

A new method is suggested for the calculation of the microcanonical cumulative reaction probability via flux autocorrelation relations. The Hamiltonian and the flux operators are computed in a discrete variable representation (DVR) and a well‐behaved representation for the Green’s operator, G(E+), is obtained by imposing absorbing boundary conditions (ABC). Applications to a one‐dimensional‐model problem and to the collinear H+H2 reaction show that the DVR‐ABC scheme provides a very efficient method for the direct calculation of the microcanonical probability, circumventing the need to compute the state‐to‐state dynamics. Our results indicate that the cumulative reaction probability can be calculated to a high accuracy using a rather small number of DVR points, confined to the vicinity of the transition state. Only limited information regarding the potential‐energy surface is therefore required, suggesting that this method would be applicable also to higher dimensionality problems, for which the complete potential surface is often unknown.

/pdf/calculation-of-the-cumulative-reaction-probability-via-a-3io07eyjhs.pdf

Calculation of the cumulative reaction probability via a discrete variable representation with absorbing boundary conditions

The revival structure of strong-field-induced rotational wave packets differs qualitatively from revival structures analyzed in the past. One of the consequences of this difference is strong enhancement of the alignment of such wave packets after turn-off of the laser pulse, under field-free conditions.

Revival Structure of Aligned Rotational Wave Packets

We review the theory of intense laser alignment of molecules and present a survey of the many recent developments in this rapidly evolving field. Starting with a qualitative discussion that emphasizes the physical mechanism responsible for laser alignment, we proceed with a detailed exposition of the underlying theory, focusing on aspects that have not been presented in the past. Application of the theory in several pedagogical illustrations is then followed by a review of the recent experimental and theoretical advances in the field. We conclude with a discussion of new directions, future opportunities, and areas where we expect intense laser alignment to play a role in the future. Throughout we emphasize the recent evolution of the method of nonadiabatic alignment from isolated diatomic molecules to complex media.

Tamar Seideman

Papers

Colloquium: Aligning molecules with strong laser pulses

Role of electron localization in intense-field molecular ionization.

Calculation of the cumulative reaction probability via a discrete variable representation with absorbing boundary conditions

Revival Structure of Aligned Rotational Wave Packets

Nonadiabatic Alignment by Intense Pulses. Concepts, Theory, and Directions