229 research outputs found
Boundary state of superstring in open string channel
We derive boundary state of superstring in the open string channel. It
describes the superconformal field theory of open string emission and
absorption by D-brane. We define the boundary state by conformal mappings from
upper half plane with operators inserted at two points corresponding to the
corners of semi-infinite strip. We obtain explicit oscillator forms
analytically for the fermion and superconformal ghost sectors. For the fermion
sector we compare this with numerical result obtained by using naive boundary
condition.Comment: 20 pages, 2 figures, PTPTeX; typos corrected, minor change
Boundary states in the open string channel and CFT near a corner
We generalize the idea of boundary states to the open string channel. They
describe emission and absorption of open strings in the presence of
intersecting D-branes. We construct the explicit oscillator representation for
the free boson and fermionic ghost. The inner product of such states describes
a disk amplitude of rectangular shape and possesses modular covariance with a
nontrivial conformal weight. We compare the result obtained here with those
obtained using two different methods, one employing the path integral formalism
and one employing the conformal anomaly. We find that all these methods give
consistent results. In our method, we must be careful in our treatment of the
singularity of the CFT near the corners. Specifically, we derive the correction
to the conformal weight of the primary field inserted at the corner, and it
gives the modular weight of the rectangle amplitude. We also carry out explicit
computations of the correlation functions.Comment: 23 pages, 4 figures, PTPTeX, v2 references added and some equations
improved, v3 style macro has been changed. BRST analysis adde
M2 to D2 revisited
We present two derivations of the multiple D2 action from the multiple
M2-brane model proposed by Bagger-Lambert and Gustavsson. The first one is to
start from Lie 3-algebra associated with given (arbitrary) Lie algebra. The Lie
3-algebra metric is not positive definite but the zero-norm generators merely
correspond to Lagrange multipliers. Following the work of Mukhi and
Papageorgakis, we derive D2-brane action from the model by giving a variable a
vacuum expectation value. The second derivation is based on the correspondence
between M2 and M5. We compactify one dimension and wind M5 brane along this
direction. This leads to a noncommutative D4 action. Multiple D2 action is then
obtained by suitably choosing the non-commutative parameter on the two-torus.
It also implies a natural interpretation to the extra generator in Lie
3-algebra, namely the winding of M5 world volume around which defines the
reduction of M theory to \IIA superstring.Comment: 20 pages, minor modifications, references adde
EVALUATION OF SPEED CHANGE IN 100 M SPRINT RUNNING
The purpose of this study was to propose a method to evaluate speed in 100m running with modified exponential equations. The speed changes in 100m sprint race of ninetysix sprinters (62 men and 34 women) were measured with a LAVEG system. The 100m race was divided into the acceleration and deceleration phases based on the maximum speed, and speed were estimated.
1) The exponential equations proposed in this study well estimated the speed change pattern of the 100m on the different record groups. The average errors between the official time and the time estimated were 0.024±0.040s in men and 0.04±0.039 in women.
2) The maximum speed was the most important factor for both men and women sprinters to achieve best performance the race.
3) The men world class sprinters accelerated quickly (large k), but reached the maximum speed later than the other sprinters, which resulted in shorter deceleration phase and smaller decreases in speed after reaching the maximum speed
Half-Integer Shapiro Steps in a Short Ballistic InAs Nanowire Josephson Junction
We report on half-integer Shapiro steps observed in an InAs nanowire
Josephson junction. We observed the Shapiro steps of the short ballistic InAs
nanowire Josephson junction and found anomalous half-integer steps in addition
to the conventional integer steps. The half-integer steps disappear as the
temperature increases or transmission of the junction decreases. These
experimental results agree closely with numerical calculation of the Shapiro
response for the skewed current phase relation in a short ballistic Josephson
junction
Production mechanism of proepitheaflagallin, a precursor of benzotropolone-type black tea pigment, derived from epigallocatechin via a bicyclo[3.2.1]octane-type intermediate
An unstable intermediate proepitheaflagallin B (2), a precursor of proepitheaflagallin (3), was isolated as an enzymatic oxidation product of (?)-epigallocatechin (1), and the structure of 2 was determined based on spectroscopic data. The structure and its decomposition revealed that the detailed production mechanism of proepitheaflagallin (3) via a bicyclo[3.2.1]octane-type intermediate was related to that of major black tea pigments, theaflavins
Dominant non-local superconducting proximity effect due to electron-electron interaction in a ballistic double nanowire
Cooper pair splitting (CPS) can induce non-local correlation between two
normal conductors coupling to a superconductor. CPS into a double
one-dimensional electron gas is an appropriate platform for extracting large
amount of entangled electron pairs and one of the key ingredients for
engineering Majorana Fermions with no magnetic field. Here we study CPS using a
Josephson junction of a gate-tunable ballistic InAs double nanowire. The
measured switching current into the two nanowires significantly larger than sum
of that into the respective nanowires, indicating the inter-wire
superconductivity dominant compared to the intra-wire superconductivity. From
dependence on the number of propagating channels in the nanowires, the observed
CPS is assigned to one-dimensional electron-electron interaction. Our results
will pave the way for utilizing one-dimensional electron-electron interaction
to reveal physics of high-efficient CPS and engineer Majorana Fermions in
double nanowire systems via CPS
Oxidation mechanism of black tea pigment theaflavin by peroxidase
A large number of black tea polyphenols remain uncharacterized because of the complexity of catechin oxidation reactions that occur during tea fermentation. In the course of our studies on black tea polyphenols, we examined the enzymatic degradation of theaflavins, which are black tea pigments having a benzotropolone chromophore. Oxidation of theaflavin with peroxidase afforded a new product named theacoumarin A together with known pigment theanaphthoquinone. The structure of the new compound was determined by spectroscopic examination and a production mechanism via theanaphthoquinone is proposed
Characterization of Proanthocyanidin Oligomers of Ephedra sinica
Ephedra sinica, an important plant in Chinese traditional medicine, contains a complex mixture of proanthocyanidin oligomers as major constituents; however, only the minor components have been chemically characterized. In this study, oligomers with relatively large molecular weights, which form the main body of the proanthocyanidin fractions, were separated by adsorption and size-exclusion chromatography. Acid-catalyzed degradation in the presence of mercaptoethanol or phloroglucinol led to the isolation of 18 fragments, the structures of which were elucidated from their experimental and TDDFT-calculated ECD spectra. The results indicated that (?)-epigallocatechin was the main extension unit, while catechin, the A-type epigallocatechin?gallocatechin dimer, and the A-type epigallocatechin homodimer, were identified as the terminal units. Among the degradation products, thioethers of gallocatechin with 3,4-cis configurations, a B-type prodelphinidin dimer, a prodelphinidin trimer with both A- and B-type linkages, and a prodelphinidin dimer with an α-substituted A-type linkage were new compounds. In addition, a phloroglucinol adduct of an A-type prodelphinidin dimer, a doubly-linked phloroglucinol adduct of epigallocatechin, and a unique product with a flavan-3-ol skeleton generated by the rearrangement of the aromatic rings were also isolated
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