1,076 research outputs found
Optimal sequencing of a set of positive numbers with the variance of the sequence's partial sums maximized
We consider the problem of sequencing a set of positive numbers. We try to
find the optimal sequence to maximize the variance of its partial sums. The
optimal sequence is shown to have a beautiful structure. It is interesting to
note that the symmetric problem which aims at minimizing the variance of the
same partial sums is proved to be NP-complete in the literature.Comment: 12 pages;Accepted for publication in Optimization Lette
Effect of Small Amounts of B and C Additions on Glass Formation and Mechanical Properties of a Zr-Base Alloy
The effect of B and C additions up to 0.4 at. % on glass formation and mechanical properties of a Zr-base alloy Vitreloy 105 was studied using various techniques. All alloys were prepared by arc melting and drop casting. Boron additions increase the glass forming ability by lowering Tm and increasing Tg. Carbon additions only lower Tm, but do not affect Tg. B and C additions occupy free space and do not harden the glass phase
CP violation in a multi-Higgs doublet model with flavor changing neutral current
We study CP violation in a multi-Higgs doublet model based on a horizontal symmetry where CKM phase is not the principal source of CP
violation. We consider two mechanisms for CP violation in this model: a) CP
violation due to complex Yukawa couplings; and b) CP violation due to
scalar-pseudoscalar Higgs boson mixings. Both mechanisms can explain the
observed CP violation in the neutral Kaon system. due to
neutral Higgs boson exchange is small in both mechanisms, but charged Higgs
boson con- tributions can be as large as for a), and for
b). CP violation in the neutral B system is, however, quite different from the
Minimal Standard
Model. The neutron Electric Dipole Moment can be as large as the present ex-
perimental bound, and can be used to constrain charged Higgs boson masses.
The electron
EDM is one order of magnitude below the experimental bound in case b) and
smaller in case a).Comment: 22 pages, Revtex, OITS-52
The controlled teleportation of an arbitrary two-atom entangled state in driven cavity QED
In this paper, we propose a scheme for the controlled teleportation of an
arbitrary two-atom entangled state
in driven cavity QED.
An arbitrary two-atom entangled state can be teleported perfectly with the help
of the cooperation of the third side by constructing a three-atom GHZ entangled
state as the controlled channel. This scheme does not involve apparent (or
direct) Bell-state measurement and is insensitive to the cavity decay and the
thermal field. The probability of the success in our scheme is 1.0.Comment: 10 page
Eta meson rescattering effects in the p + 6Li --> eta + 7Be reaction near threshold
The p + 6Li --> eta + 7Be reaction has been investigated with an emphasis on
the eta meson and 7Be interaction in the final state. Considering the 6Li and
7Be nuclei to be alpha-d and alpha-3He clusters respectively, the reaction is
modelled to proceed via the p + d [alpha] --> 3He [\alpha] + eta reaction with
the alpha remaining a spectator. The eta meson interacts with 7Be via multiple
scatterings on the 3He and alpha clusters inside 7Be. The individual eta-3He
and eta-alpha scatterings are evaluated using few body equations for the eta-3N
and eta-4N systems with a coupled channel eta-N interaction as an input.
Calculations including four low-lying states of 7Be lead to a double hump
structure in the total cross section corresponding to the and angular momentum states. The humps
arise due to the off-shell rescattering of the eta meson on the 7Be nucleus in
the final state.Comment: New results and references adde
Plane waves with weak singularities
We study a class of time dependent solutions of the vacuum Einstein equations
which are plane waves with weak null singularities. This singularity is weak in
the sense that though the tidal forces diverge at the singularity, the rate of
divergence is such that the distortion suffered by a freely falling observer
remains finite. Among such weak singular plane waves there is a sub-class which
do not exhibit large back reaction in the presence of test scalar probes.
String propagation in these backgrounds is smooth and there is a natural way to
continue the metric beyond the singularity. This continued metric admits string
propagation without the string becoming infinitely excited. We construct a one
parameter family of smooth metrics which are at a finite distance in the space
of metrics from the extended metric and a well defined operator in the string
sigma model which resolves the singularity.Comment: 22 pages, Added references and clarifying comment
Doping effect on the anomalous behavior of the Hall effect in electron-doped superconductor NdCeCuO
Transport properties of NdCeCuO single crystal films
are investigated in magnetic fields up to 9T at =(0.4-4.2)K. An analysis
of normal state (at ) Hall coefficient dependence on Ce
doping takes us to a conclusion about the existence both of electron-like and
hole-like contributions to transport in nominally electron-doped system. In
accordance with (x) analysis an anomalous sign reversal of Hall effect
in mixed state at may be ascribed to a flux-flow regime for two
types of carriers with opposite charges.Comment: 14 pages, 5 figure
Diffusion in Stationary Flow from Mesoscopic Non-equilibrium Thermodynamics
We analyze the diffusion of a Brownian particle in a fluid under stationary
flow. By using the scheme of non-equilibrium thermodynamics in phase space, we
obtain the Fokker-Planck equation which is compared with others derived from
kinetic theory and projector operator techniques. That equation exhibits
violation of the fluctuation dissipation-theorem. By implementing the
hydrodynamic regime described by the first moments of the non-equilibrium
distribution, we find relaxation equations for the diffusion current and
pressure tensor, allowing us to arrive at a complete description of the system
in the inertial and diffusion regimes. The simplicity and generality of the
method we propose, makes it applicable to more complex situations, often
encountered in problems of soft condensed matter, in which not only one but
more degrees of freedom are coupled to a non-equilibrium bath.Comment: 10 pages, accepted in Phys. Rev.
Nonlinear Realization of N=2 Superconformal Symmetry and Brane Effective Actions
Due to the incompatibility of the nonlinear realization of superconformal
symmetry and dilatation symmetry with the dilaton as the compensator field, in
the present paper it shows an alternative mechanism of spontaneous breaking the
N=2 superconformal symmetry to the N=0 case. By using the approach of nonlinear
transformations it is found that it leads to a space-filling brane theory with
Weyl scale W(1,3) symmetry. The dynamics of the resulting Weyl scale invariant
brane, along with that of other Nambu-Goldstone fields, is derived in terms of
the building blocks of the vierbein and the covariant derivative from the
Maurer-Cartan oneforms. A general coupling of the matter fields localized on
the brane world volume to these NG fields is also constructed.Comment: 22 pages, more references and comments are adde
Diffusion in Stationary Flow from Mesoscopic Non-equilibrium Thermodynamics
We analyze the diffusion of a Brownian particle in a fluid under stationary
flow. By using the scheme of non-equilibrium thermodynamics in phase space, we
obtain the Fokker-Planck equation which is compared with others derived from
kinetic theory and projector operator techniques. That equation exhibits
violation of the fluctuation dissipation-theorem. By implementing the
hydrodynamic regime described by the first moments of the non-equilibrium
distribution, we find relaxation equations for the diffusion current and
pressure tensor, allowing us to arrive at a complete description of the system
in the inertial and diffusion regimes. The simplicity and generality of the
method we propose, makes it applicable to more complex situations, often
encountered in problems of soft condensed matter, in which not only one but
more degrees of freedom are coupled to a non-equilibrium bath.Comment: 10 pages, accepted in Phys. Rev.
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