AdS/CFT correspondence via R-current correlation functions revisited

Motivated by realizing open/closed string duality in the work by Gopakumar [Phys. Rev. D70:025009,2004], we study two and three-point correlation functions of R-current vector fields in N=4 super Yang-Mills theory. These correlation functions in free field limit can be derived from the worldline formalism and written as heat kernel integrals in the position space. We show that reparametrizing these integrals converts them to the expected AdS supergravity results which are known in terms of bulk to boundary propagator. We expect that this reparametrization corresponds to transforming open string moduli parameterization to the closed string ones.Comment: 23 pages, v2: calculations clarified, references added, v3: sections re-arranged with more explanations, 4 figures and an appendix adde

Energy States of Colored Particle in a Chromomagnetic Field

The unitary transformation, which diagonalizes squared Dirac equation in a constant chromomagnetic field is found. Applying this transformation, we find the eigenfunctions of diagonalized Hamiltonian, that describe the states with definite value of energy and call them energy states. It is pointed out that, the energy states are determined by the color interaction term of the particle with the background chromofield and this term is responsible for the splitting of the energy spectrum. We construct supercharge operators for the diagonal Hamiltonian, that ensure the superpartner property of the energy states.Comment: 25 pages, some calculation details have been removed, typos correcte

Unoccupied Topological States on Bismuth Chalcogenides

The unoccupied part of the band structure of topological insulators Bi$_2$Te$_{x}$Se$_{3-x}$ ($x=0,2,3$) is studied by angle-resolved two-photon photoemission and density functional theory. For all surfaces linearly-dispersing surface states are found at the center of the surface Brillouin zone at energies around 1.3 eV above the Fermi level. Theoretical analysis shows that this feature appears in a spin-orbit-interaction induced and inverted local energy gap. This inversion is insensitive to variation of electronic and structural parameters in Bi$_2$Se$_3$ and Bi$_2$Te$_2$Se. In Bi$_2$Te$_3$ small structural variations can change the character of the local energy gap depending on which an unoccupied Dirac state does or does not exist. Circular dichroism measurements confirm the expected spin texture. From these findings we assign the observed state to an unoccupied topological surface state

Weak Boson Production Amplitude Zeros; Equalities of the Helicity Amplitudes

We investigate the radiation amplitude zeros exhibited by many Standard Model amplitudes for triple weak gauge boson production processes. We show that $WZ\gamma$ production amplitudes have especially rich structure in terms of zeros, these amplitudes have zeros originating from several different sources. It is also shown that TYPE I current null zone is the special case of the equality of the specific helicity amplitudes.Comment: 27 pages, 12 figures, 2 table

Femtosecond primary charge separation in Synechocystis sp. PCC 6803 photosystem I

AbstractThe ultrafast (<100fs) conversion of delocalized exciton into charge-separated state between the primary donor P700 (bleaching at 705nm) and the primary acceptor A0 (bleaching at 690nm) in photosystem I (PS I) complexes from Synechocystis sp. PCC 6803 was observed. The data were obtained by application of pump–probe technique with 20-fs low-energy pump pulses centered at 720nm. The earliest absorbance changes (close to zero delay) with a bleaching at 690nm are similar to the product of the absorption spectrum of PS I complex and the laser pulse spectrum, which represents the efficiency spectrum of the light absorption by PS I upon femtosecond excitation centered at 720nm. During the first ∼60fs the energy transfer from the chlorophyll (Chl) species bleaching at 690nm to the Chl bleaching at 705nm occurs, resulting in almost equal bleaching of the two forms with the formation of delocalized exciton between 690-nm and 705-nm Chls. Within the next ∼40fs the formation of a new broad band centered at ∼660nm (attributed to the appearance of Chl anion radical) is observed. This band decays with time constant simultaneously with an electron transfer to A1 (phylloquinone). The subtraction of kinetic difference absorption spectra of the closed (state P700+A0A1) PS I reaction center (RC) from that of the open (state P700A0A1) RC reveals the pure spectrum of the P700+A0− ion–radical pair. The experimental data were analyzed using a simple kinetic scheme: An* →k1 [(PA0)*A1→<100fs P+A0−A1] →k2P+A0A1−, and a global fitting procedure based on the singular value decomposition analysis. The calculated kinetics of transitions between intermediate states and their spectra were similar to the kinetics recorded at 694 and 705nm and the experimental spectra obtained by subtraction of the spectra of closed RCs from the spectra of open RCs. As a result, we found that the main events in RCs of PS I under our experimental conditions include very fast (<100fs) charge separation with the formation of the P700+A0−A1 state in approximately one half of the RCs, the ∼5-ps energy transfer from antenna Chl* to P700A0A1 in the remaining RCs, and ∼25-ps formation of the secondary radical pair P700+A0A1−

Spin and energy transfer in nanocrystals without transport of charge

We describe a mechanism of spin transfer between individual quantum dots that does not require tunneling. Incident circularly-polarized photons create inter-band excitons with non-zero electron spin in the first quantum dot. When the quantum-dot pair is properly designed, this excitation can be transferred to the neighboring dot via the Coulomb interaction with either {\it conservation} or {\it flipping} of the electron spin. The second dot can radiate circularly-polarized photons at lower energy. Selection rules for spin transfer are determined by the resonant conditions and by the strong spin-orbit interaction in the valence band of nanocrystals. Coulomb-induced energy and spin transfer in pairs and chains of dots can become very efficient under resonant conditions. The electron can preserve its spin orientation even in randomly-oriented nanocrystals.Comment: 13 pages, 3 figure

The Period Changes of the Cepheid RT Aurigae

Observations of the light curve for the 3.7-day Cepheid RT Aur both before and since 1980 indicate that the variable is undergoing an overall period increase, amounting to +0.082 +-0.012 s/yr, rather than a period decrease, as implied by all observations prior to 1980. Superposed on the star's O-C variations is a sinusoidal trend that cannot be attributed to random fluctuations in pulsation period. Rather, it appears to arise from light travel time effects in a binary system. The derived orbital period for the system is P = 26,429 +-89 days (72.36 +-0.24 years). The inferred orbital parameters from the O-C residuals differ from those indicated by existing radial velocity data. The latter imply the most reasonable results, namely a1 sin i = 9.09 (+-1.81) x 10^8 km and a minimum secondary mass of M2 = 1.15 +-0.25 Msun. Continued monitoring of the brightness and radial velocity changes in the Cepheid are necessary to confirm the long-term trend and to provide data for a proper spectroscopic solution to the orbit.Comment: Accepted for publication in PASP (November 2007

Pharmacy Compounding Regulation in the German Pharmaceutical Market. Part 1. Basic Regulatory Provisions (Review)

SCIENTIFIC RELEVANCE. There is a need to move towards an appropriate system of quality assurance in pharmacy compounding. At the same time, the development of a Russian regulatory system for pharmacy compounding requires a broad understanding of international experience.AIM. This study aimed at analysing the basic principles of pharmacy compounding regulation in the Federal Republic of Germany in order to identify best practices and determine ways to improve the legal and regulatory framework for compounding pharmacies in the Russian Federation.DISCUSSION. According to German law, pharmacies may dispense compounded medicinal products on an oral request from a patient. The German regulatory framework provides a mechanism delineating medicinal products compounded by pharmacies and those manufactured by pharmaceutical companies. The geographical and quantitative restrictions combined with the neutral pricing policy for pharmacies facilitate the establishment of a highly effective pharmaceutical supply system. In practice, this system helps set uniform prices for medicinal products throughout Germany while preventing pharmacy chains from monopolising the pharmaceutical market. These regulations can be considered regulatory mechanisms operating at the regional (land) level. Moreover, it is of key importance that German legislation divides compounded medicinal products into stock and extemporaneous preparations.CONCLUSIONS. German pharmaceutical practice features a number of innovations that can be borrowed for Russian pharmaceutical practice. Russian pharmaceutical legislation may benefit from adopting the concept of a “request from an individual” for dispensing compounded medicinal products that do not contain prescription-only active pharmaceutical ingredients (APIs). In order to improve the efficiency of the use of pharmaceutical-quality raw materials, including APIs, it is necessary to identify cases in which regular pharmacies can receive or purchase compounded medicinal products from compounding pharmacies and cases in which compounding pharmacies can purchase APIs from other compounding pharmacies. The authors recommend considering the possibility of defining the role, functions, and powers of self-regulating professional pharmacy organisations at various levels of governance in this social sphere of activity. Furthermore, the authors recommend creating a Russian mechanism to mitigate the risks of stock shortages and/or limited supply of medicinal products that would be similar to the German “standard authorisation” system and would encompass compounding pharmacies and pharmaceutical companies