8,891 research outputs found
Solving Lauricella String Scattering Amplitudes through Recurrence Relations
We show that there exist infinite number of recurrence relations valid for
all energies among the open bosonic string scattering amplitudes (SSA) of three
tachyons and one arbitrary string state, or the Lauricella SSA. Moreover, these
infinite number of recurrence relations can be used to solve all the Lauricella
SSA and express them in terms of one single four tachyon amplitude. These
results extend the solvability of SSA at the high energy, fixed angle
scattering limit and those at the Regge scattering limit discovered previously.Comment: 19 pages. v2: Fig.1 adde
String Scattering Amplitudes and Deformed Cubic String Field Theory
We study string scattering amplitudes by using the deformed cubic string
field theory which is equivalent to the string field theory in the proper-time
gauge. The four-string scattering amplitudes with three tachyons and an
arbitrary string state are calculated. The string field theory yields the
string scattering amplitudes evaluated on the world sheet of string scattering
whereas the coventional method, based on the first quantized theory brings us
the string scattering amplitudes defined on the upper half plane. For the
highest spin states, generated by the primary operators, both calculations are
in perfect agreement. In this case, the string scattering amplitudes are
invariant under the conformal transformation, which maps the string world sheet
onto the upper half plane. If the external string states are general massive
states, generated by non-primary field operators, we need to take into account
carefully the conformal transformation between the world sheet and the upper
half plane. We show by an explicit calculation that the string scattering
amplitudes calculated by using the deformed cubic string field theory transform
into those of the first quantized theory on the upper half plane by the
conformal transformation, generated by the Schwarz-Christoffel mapping.Comment: 12 pages, 2 figures, references adde
The SL(K+3,C) Symmetry of the Bosonic String Scattering Amplitudes
We discover that the exact string scattering amplitudes (SSA) of three
tachyons and one arbitrary string state, or the Lauricella SSA (LSSA), in the
26D open bosonic string theory can be expressed in terms of the basis functions
in the infinite dimensional representation space of the SL(K+3,C) group. In
addition, we find that the K+2 recurrence relations among the LSSA discovered
by the present authors previously can be used to reproduce the Cartan
subalgebra and simple root system of the SL(K+3,C) group with rank K+2. As a
result, the SL(K+3,C) group can be used to solve all the LSSA and express them
in terms of one amplitude. As an application in the hard scattering limit, the
SL(K+3,C) group can be used to directly prove Gross conjecture [1-3], which was
previously corrected and proved by the method of decoupling of zero norm states
[4-10].Comment: 19 pages, no figure. v2: 20 pages, typos corrected and Eqs. added.
v3: 24 pages, Examples in sec. II added,"Discussion" added, to be published
in Nucl.Phys.
Recommended from our members
Cochlea-sparing acoustic neuroma treatment with 4Ï€ radiation therapy.
PurposeThis study investigates whether 4π noncoplanar radiation therapy can spare the cochleae and consequently potentially improve hearing preservation in patients with acoustic neuroma who are treated with radiation therapy.Methods and materialsClinical radiation therapy plans for 30 patients with acoustic neuroma were included (14 stereotactic radiation surgery [SRS], 6 stereotactic radiation therapy [SRT], and 10 intensity modulated radiation therapy [IMRT]). The 4π plans were created for each patient with 20 optimal beams selected using a greedy column generation method and subsequently recalculated in Eclipse for comparison. Organ-at-risk (OAR) doses, homogeneity index, conformity, and tumor control probability (TCP) were compared. Normal tissue complication probability (NTCP) was calculated for sensorineural hearing loss (SNHL) at 3 and 5 years posttreatment. The dose for each plan was then escalated to achieve 99.5% TCP.Results4π significantly reduced the mean dose to both cochleae by 2.0 Gy (32%) for SRS, 3.2 Gy (29%) for SRT, and 10.0 Gy (32%) for IMRT. The maximum dose to both cochleae was also reduced with 4π by 1.6 Gy (20%), 2.2 Gy (15%), and 7.1 Gy (18%) for SRS, SRT, and IMRT plans, respectively. The reductions in mean/maximum brainstem dose with 4π were also statistically significant. Mean doses to other OARs were reduced by 19% to 56% on average. 4π plans had a similar CN and TCP, with a significantly higher average homogeneity index (0.93 vs 0.92) and significantly lower average NTCP for SNHL at both 3 years (30.8% vs 40.8%) and 5 years (43.3% vs 61.7%). An average dose escalation of approximately 116% of the prescription dose achieved 99.5% TCP, which resulted in 32.6% and 43.4% NTCP for SNHL at 3 years and 46.4% and 64.7% at 5 years for 4π and clinical plans, respectively.ConclusionsCompared with clinical planning methods, optimized 4π radiation therapy enables statistically significant sparing of the cochleae in acoustic neuroma treatment as well as lowering of other OAR doses, potentially reducing the risk of hearing loss
Influence of Correlated Disorder Potentials on the Levitation of Current Carrying States in the Quantum Hall Effect
The disorder driven quantum Hall to insulator transition is investigated for
a two-dimensional lattice system. We consider a Gaussian correlated random
potential, study the behaviour of the current carrying states and trace their
energetical position when the disorder strength is increased. Our results
qualitatively resemble those obtained previously for exponentially correlated
disorder potentials. We find both the downward movement of the anti-Chern
states as well as the floating up of the Chern states across the Landau gap
which is sometimes masked by the global broadening of the tight binding band.Comment: 4 pages, 3 figures, EP2DS-14 Pragu
Functional renormalization group and variational Monte Carlo studies of the electronic instabilities in graphene near 1/4 doping
We study the electronic instabilities of near 1/4 electron doped graphene
using the functional renormalization group (FRG) and variational Monte-Carlo
method. A modified FRG implementation is utilized to improve the treatment of
the von Hove singularity. At 1/4 doping the system is a chiral spin density
wave state exhibiting the anomalous quantized Hall effect, or equivalently a
Chern insulator. When the doping deviates from 1/4, the
Cooper pairing becomes the leading instability. Our results suggest near 1/4
electron or hole doped graphene is a fertile playground for the search of Chern
insulators and superconductors.Comment: 7 pages, 8 figures, with technical details, published versio
The symmetry of string scatterings from D-branes
By using the solvability of Lauricella function with nonpositive
integer , we show that each scattering or decay process of string
and D-brane states at \textit{arbitrary} mass levels can be expressed in terms
of a single Lauricella function. This result extends the previous exact
symmetry of tree-level open bosonic string theory to
include the D-brane.Comment: 15 pages, no figure. arXiv admin note: text overlap with
arXiv:2108.06326. v2: 18 pages. Final in Nucl.Phys.
Stringy scaling of n-point Regge string scattering amplitudes
We discover a stringy scaling behavior for a class of n-point Regge string
scattering amplitudes (RSSA). The number of independent kinematics variables is
found to be reduced by dim M.Comment: 33 pages, 1 figur
- …