5,148 research outputs found
Differential Geometrical Formulation of Gauge Theory of Gravity
Differential geometric formulation of quantum gauge theory of gravity is
studied in this paper. The quantum gauge theory of gravity which is proposed in
the references hep-th/0109145 and hep-th/0112062 is formulated completely in
the framework of traditional quantum field theory. In order to study the
relationship between quantum gauge theory of gravity and traditional quantum
gravity which is formulated in curved space, it is important to find the
differential geometric formulation of quantum gauge theory of gravity. We first
give out the correspondence between quantum gauge theory of gravity and
differential geometry. Then we give out differential geometric formulation of
quantum gauge theory of gravity.Comment: 10 pages, no figur
Electronic structure near an impurity and terrace on the surface of a 3-dimensional topological insulator
Motivated by recent scanning tunneling microscopy experiments on surfaces of
BiSb\cite{yazdanistm,gomesstm} and
BiTe,\cite{kaptunikstm,xuestm} we theoretically study the electronic
structure of a 3-dimensional (3D) topological insulator in the presence of a
local impurity or a domain wall on its surface using a 3D lattice model. While
the local density of states (LDOS) oscillates significantly in space at
energies above the bulk gap, the oscillation due to the in-gap surface Dirac
fermions are very weak. The extracted modulation wave number as a function of
energy satisfies the Dirac dispersion for in-gap energies and follows the
border of the bulk continuum above the bulk gap. We have also examined
analytically the effects of the defects by using a pure Dirac fermion model for
the surface states and found that the LDOS decays asymptotically faster at
least by a factor of 1/r than that in normal metals, consistent with the
results obtained from our lattice model.Comment: 7 pages, 5 figure
Storage and retrieval of continuous-variable polarization-entangled cluster states in atomic ensembles
We present a proposal for storing and retrieving a continuous-variable
quadripartite polarization-entangled cluster state, using macroscopic atomic
ensembles in a magnetic field. The Larmor precession of the atomic spins leads
to a symmetry between the atomic canonical operators. In this scheme, each of
the four spatially separated pulses passes twice through the respective
ensemble in order to map the polarization-entangled cluster state onto the
long-lived atomic ensembles. The stored state can then be retrieved by another
four read-out pulses, each crossing the respective ensemble twice. By
calculating the variances, we analyzed the fidelities of the storage and
retrieval, and our scheme is feasible under realistic experimental conditions.Comment: 6 pages, 4 figure
Flank gland-secreted putative chemosignals pertaining to photoperiod, endocrine states, and sociosexual behavior in golden hamsters
Behavioral studies have shown that flank glands are involved in chemical communication in golden hamsters Mesocricetus auratus but little chemical analysis has been conducted on volatiles arising from these glands. Using gas chromatography- mass spectrometry, we detected compounds from the flank glands of males, only eight of which were also produced in females. Based on these chemical data we performed a number of further experiments. By manipulating light we found that males exposed to short-photoperiods developed smaller flank glands than those exposed to long-photoperiods. Six flank gland volatiles reduced in relative abundance, which possibly coded for reproductive status of males of this seasonally breeding hamster species. Through dyadic encounters, we were able to induce the formation of dominant-subordinate relationships and show that two glandular compounds became high in relative abundance and may function as dominance pheromones. Castration eliminated all male-specific compounds resulting from flank glands, but bilateral ovariectomies only affected one compound in females. Once these ovariectomized females were treated with testosterone, their glandular compounds resembled those of males, suggesting these compounds are under the main control of androgen. Two female putative pheromones, tetradecanoic acid and hexadecanoic acid, were used in binary choice tests and were both found to attract males over females. Applying a solution of these pheromone compounds to adult males also suppressed their agonistic behavior
Expression of VP60 gene from rabbit haemorrhagic disease virus (RHDV) YL strain under control of the ats1A promoter in tobacco
The VP60 gene from rabbit haemorrhagic disease virus (RHDV) YL strain in Northeast of China, under control of the ats1A promoter from Rubisco small subunit genes of Arabidopsis thaliana, was introduced into the transfer deoxyribonucleic acid (T-DNA) region of plant transfer vector pCAMBIA1300 and transferred to tobacco (Nicotiana tabacum cv. Petit Havanna SR1) with Agrobacterium tumefaciens-mediated method. Polymerase chain reaction (PCR) reverse transcription(RT) and -PCR analysis of the transformed tobacco plants confirmed the integration of the VP60 gene copy into the plant DNA and VP60 gene transcription produced. Western blot analysis revealed that the VP60 protein was expressed in tobacco under control of ats1A promoter.Key words: Agrobacterium tumefaciens, rabbit haemorrhagic disease virus (RHDV), VP60 protein, ats1A promoter, plant-derived vaccine
Synthesis of steel slag ceramics: chemical composition and crystalline phases of raw materials
5-Methyl-1,2,3,3a-tetraÂhydroÂbenzo[e]pyrroloÂ[2,1-b][1,3]oxazepin-10(5H)-one
The asymmetric unit of the title compound, C13H15NO2, the main product of a photoreaction, contains two crystallographically independent molÂecules. In both molÂecules, the conformation of the seven-membered ring is twist sofa and that of the five-membered rings is envelope. In the crystal, molÂecules are linked by weak interÂmolecular C—H⋯O hydrogen bonds
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