4,338 research outputs found
Zero-norm states and stringy symmetries
We identify spacetime symmetry charges of 26D open bosonic string theory from
an infinite number of zero-norm states (ZNS) with arbitrary high spin in the
old covariant first quantized string spectrum. We give various evidences to
support this identification. These include massive sigma-model calculation,
Witten string field theory calculation, 2D string theory calculation and, most
importantly, three methods of high-energy stringy scattering amplitude
calculations. The last calculations explicitly prove Gross's conjectures in
1988 on high energy symmetry of string theory.Comment: 6 pages. Talks presented by Jen-Chi Lee at XXVIII Spanish Relativity
Meeting (ERE2005),"A Century of Relativity Physics",Oviedo,Spain,6-10 Sep
2005 and "4th Meeting on constrained Dynamics and Quantum Gravity",Cala
Gonone,Sardinia,Italy,12-16 Sep 2005. To appear in the Journal of Physics:
Conference Serie
Linear Relations and their Breakdown in High Energy Massive String Scatterings in Compact Spaces
We calculate high energy massive scattering amplitudes of closed bosonic
string compactified on the torus. For each fixed mass level with given
quantized and winding momenta ((m/R),(1/2)nR), we obtain infinite linear
relations among high energy scattering amplitudes of different string states.
For some kinematic regimes, we discover that linear relations with N_{R}=N_{L}
break down and, simultaneously, the amplitudes enhance to power-law behavior
instead of the usual expoential fall-off behavior at high energies. It is the
space-time T-duality symmetry that plays a role here. This result is consistent
with the coexistence of the linear relations and the softer exponential
fall-off behavior of high energy string scattering amplitudes as we pointed out
prevously. It is also reminiscent of our previous work on the power-law
behavior of high energy string/domain-wall scatterings.Comment: 18 pages, 1 figur
Scatterings of Massive String States from D-brane and Their Linear Relations at High Energies
We study scatterings of bosonic massive closed string states at arbitrary
mass levels from D-brane. We discover that all the scattering amplitudes can be
expressed in terms of the generalized hypergeometric function with special
arguments, which terminates to a finite sum and, as a result, the whole
scattering amplitudes consistently reduce to the usual beta function. For the
simple case of D-particle, we explicitly calculate high-energy limits of a
series of the above scattering amplitudes for arbitrary mass levels, and derive
infinite linear relations among them for each fixed mass level. The ratios of
these high-energy scattering amplitudes are found to be consistent with the
decoupling of high-energy zero-norm states of our previous works.Comment: 19 pages, no figure. v2:some minor corrections, refs added. v3:minor
changes and final in Nucl.Phys.
High-energy String Scatterings of Compactified Open String
We calculate high-energy massive string scattering amplitudes of compactified
open string. We derive infinite linear relations, or stringy symmetries, among
soft high-energy string scattering amplitudes of different string states in the
Gross kinematic regime (GR). In addition, we systematically analyze all hard
power-law and soft exponential fall-off regimes of high-energy compactified
open string scatterings by comparing the scatterings with their 26D
noncompactified counterparts. In particular, we discover the existence of a
power-law regime at fixed angle and an exponential fall-off regime at small
angle for high-energy compactified open string scatterings. The linear
relations break down as expected in all power-law regimes. The analysis can be
extended to the high-energy scatterings of the compactified closed string,
which corrects and extends the previous results in [28] .Comment: 16 pages, 1 table. v2:typos corrected,references added. v3,v4:Eq.(26)
typos. Eq.(27) correcte
High-energy zero-norm states and symmetries of string theory
High-energy limit of zero-norm states (HZNS) in the old covariant first
quantized (OCFQ) spectrum of the 26D open bosonic string, together with the
assumption of a smooth behavior of string theory in this limit, are used to
derive infinitely many linear relations among the leading high-energy, fixed
angle behavior of four point functions of different string states. As a result,
ratios among all high-energy scattering amplitudes of four arbitrary string
states can be calculated algebraically and the leading order amplitudes can be
expressed in terms of that of four tachyons as conjectured by Gross in 1988. A
dual calculation can also be performed and equivalent results are obtained by
taking the high-energy limit of Virasoro constraints. Finally, as a consistent
sample calculation, we compute all high-energy scattering amplitudes of three
tachyons and one massive state at the leading order by saddle-point
approximation to justify our results.Comment: 10 pages, no figure, modifications of text and reference
Effect of lifestyle factors on risk of mortality associated with influenza in elderly people
published_or_final_versio
Strain-gradient-induced magnetic anisotropy in straight-stripe mixed-phase bismuth ferrites: An insight into flexomagnetic phenomenon
Implementation of antiferromagnetic compounds as active elements in
spintronics has been hindered by their insensitive nature against external
perturbations which causes difficulties in switching among different
antiferromagnetic spin configurations. Electrically-controllable strain
gradient can become a key parameter to tune the antiferromagnetic states of
multiferroic materials. We have discovered a correlation between an
electrically-written straight-stripe mixed-phase boundary and an in-plane
antiferromagnetic spin axis in highly-elongated La-5%-doped BiFeO thin
films by performing polarization-dependent photoemission electron microscopy in
conjunction with cluster model calculations. Model Hamiltonian calculation for
the single-ion anisotropy including the spin-orbit interaction has been
performed to figure out the physical origin of the link between the strain
gradient present in the mixed phase area and its antiferromagnetic spin axis.
Our findings enable estimation of the strain-gradient-induced magnetic
anisotropy energy per Fe ion at around 510 eV m, and provide a
new pathway towards an electric-field-induced 90 rotation of
antiferromagnetic spin axis at room temperature by flexomagnetism.Comment: 32 pages, 5 figure
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