Novel approach to a perfect lens

Within the framework of an exact analytical solution of Maxwell equations in a space domain, it is shown that optical scheme based on a slab with negative refractive index (n = −1) (Veselago lens or Pendry lens) does not possess focusing properties in the usual sense. In fact, the energy in such systems does not go from object to its “image,” but from object and its “image” to an intersection point inside a metamaterial layer, or vice versa. A possibility of applying this phenomenon to a creation of entangled states of two atoms is discussed. The article is published in the original.     

Negative refraction makes a perfect lens

With a conventional lens sharpness of the image is always limited by the wavelength of light. An unconventional alternative to a lens, a slab of negative refractive index material, has the power to focus all Fourier components of a 2D image, even those that do not propagate in a radiative manner. Such "superlenses" can be realized in the microwave band with current technology. Our simulations show that a version of the lens operating at the frequency of visible light can be realized in the form of a thin slab of silver. This optical version resolves objects only a few nanometers across.     

部分相干余弦高斯光束在左手材料中的光强分布

基于积分衍射理论和相干偏振理论,研究了部分相干余弦高斯光束在左手材料中的光强的分布。研究结果表明:中心光强随工作频率增大,先增大后逐渐趋于稳定,但是随相干参量增大而减小;横向光强随相干参量增大而减小,随偏心参量增大光强的最大峰值不变,但是光强的峰值数目在不断增加。     

Lorentz covariance of the canonical perfect lens

The canonical perfect lens—comprising three slabs, each made of a linear, homogeneous, bianisotropic material with orthorhombic symmetry—is Lorentz covariant.     

Optical implementation of perfect shuffle using Billet lens

This paper presents an optical system to implement perfect shuffle network us-ing Billet lens.Optical perfect shuffle network of high density and large capacity can be real-ized in this system with higher optical efficiency.     

The almost perfect lens and focusing of evanescent waves

We propose a general method for evaluating the field in the focal region of nearly perfect one-dimensional lenses, and study how evanescent waves contribute to the electric field behind subwavelength apertures. The approach presented here may give a better insight into how to shape and focus evanescent waves.     

A near perfect Pendry lens: Projecting properties of a thin metal layer

We consider the field of an evanescent wave in a space with a thin metal layer (? < 0). The wavenumber of the evanescent wave appreciably exceeds the wavenumber k ₀ = 2π/λ₀ of a uniform plane wave in spatial regions adjacent to the metal. In accordance with the Pendry result (2000), the field behind the metal layer is amplified as compared to the field in the absence of the layer. Pendry predicted this effect for a metal whose dielectric permittivity is ? = ?1, whereas we show that the effect can also be observed for ? = ?15 and for arbitrarily thick adjacent regions. This extends the range of possible applications of the effect. We find that the losses in the metal only weakly affect the image quality behind the metal layer.     

Universal features of the time evolution of evanescent modes in a left-handed perfect lens

The time evolution of evanescent modes in Pendry's perfect lens proposal for ideally lossless and homogeneous, left-handed materials is analyzed. We show that time development of subwavelength resolution exhibits universal features, independent of model details. This is due to the unavoidable near degeneracy of surface electromagnetic modes in the deep subwavelength region. By means of a mechanical analog, it is shown that an intrinsic time scale (missed in stationary studies) has to be associated with any desired lateral resolution. A time-dependent cutoff length emerges, removing the problem of divergences claimed to invalidate Pendry's proposal.     

Bohr did not make an elementary blunder

It is shown that a recent attempt to disprove the scaling properties of the Bohr stopping formula by molecular-dynamics simulation is based on a misreading. The proposed generalized scaling law is shown to be incorrect.     

含左手材料光纤的表面模特性

在弱导条件下,利用Maxwell方程组,对纤芯是左手材料,包层是右手材料的光纤表面模进行了研究,得到了TE (TM)、 EH和 HE表面模的色散方程,.根据色散方程,画出了相应表面模和含左手材料光纤导模的色散曲线.比较这些色散曲线,发现了含左手材料光纤表面模一些新的特性.     

Theoretical Research on a Kind of Quantum Left-handed Metamaterial

Recently, research on left-handed materials （LHMs） has attracted considerable attentions. The LHMs are a kind of metameterial which have negative permittivity and negative permeability, which lead to negative refractive index in a frequency range. The LHMs that have been available so far are in the microwave range and are usually composed of classical particles, such as split-ring resonators. Some quantum phenomena such as spontaneous emission of atoms in the LHMs which are considered to be ＇classical background＇ have also been investigated. Many potential applications of LHMs have been proposed, such as superlenses which, in principle, can achieve arbitrary subwavelength resolution.     

Entanglement is not necessary for perfect discrimination between unitary operations

We show that a unitary operation (quantum circuit) secretly chosen from a finite set of unitary operations can be determined with certainty by sequentially applying only a finite amount of runs of the unknown circuit. No entanglement or joint quantum operations are required in our scheme. We further show that our scheme is optimal in the sense that the number of the runs is minimal when discriminating only two unitary operations.     

Compatible stochastic observables that do not commute

It is shown that stochastic observables defined by an instrument need not, and generally do not, commute.     

Loschmidt's and Zermelo's paradoxes do not exist

A strict operational (i.e., informational) analysis of the meaning of preparing a system to realize the paradoxes of Loschmidt or Zermelo is made. Where reversal or recurrence are operationally realizable, no contradiction with the irreversible nature of macroscopic operations occurs. Paradox results either from neglecting irreversible phenomena in the means for preparing a reversed state, or from confusing elements or ensembles, which are meaningful in microstate language but meaningless operationally, with preparable macrostates, whoserepresentation in microstate language is an ensemble whose very definition is incompatible with that of any paradox-generating element or ensemble,Supported in part by NSF Grant No. GN 534.1.     

Why dilatation generators do not generate dilatations

We show that the Ward identities associated with broken scale invariance contain anomalies in renormalized perturbation theory. In low orders, these anomalies can be absorbed into a redefinition of the scale dimensions of the fields in the theory, but in higher orders this is not possible. Also, these anomalies cannot be removed by studying the Green's functions for objects other than canonical fields, e.g., currents. These results are established to first nontrivial order in perturbation theory by explicit Feynman calculations (which give us information at all momentum transfers), and in higher orders by the method of Callan and Symanzik (which gives information only at zero momentum transfer). The two approaches are consistent within their common domain of validity. Two appendices contain self-contained treatments of the formal canonical theory of scale and conformal transformations and of the derivation of Ward identities. In another appendix, we derive the Callan-Symanzik equations for Green's functions of currents, and show that no redefinition of scale dimension is necessary for these objects, although the other anomalies remain.