2,338 research outputs found
Quantum Energy Teleportation with a Linear Harmonic Chain
A protocol of quantum energy teleportation is proposed for a one-dimensional
harmonic chain. A coherent-state POVM measurement is performed to coupled
oscillators of the chain in the ground state accompanied by energy infusion to
the system. This measurement consumes a part of ground state entanglement.
Depending on the measurement result, a displacement operation is performed on a
distant oscillator accompanied by energy extraction from the zero-point
fluctuation of the oscillator. We find that the amount of consumed entanglement
is bounded from below by a positive value that is proportional to the amount of
teleported energy.Comment: 23 pages, 10 figures, analysis for non-critical case is added,
accepted for publication in PR
Quark Droplets in the NJL Mean Field
We study the conditions for the existence of stable quark matter in the
Nambu--Jona-Lasinio mean field at zero temperature and discuss its
interpretation.Comment: 6 pages, LaTeX, 4 eps-figures included, to appear in the Proc. of the
workshop 'QCD at Finite Baryon Density', Bielefeld, April 27-30, 199
Stability of color-flavor locked strangelets
The stability of color-flavor locked (CFL) strangelets is studied in the
three-flavor Nambu--Jona-Lasinio model. We consider all quark flavors to be
massless, for simplicity. By making use of the multiple reflection expansion,
we explicitly take into account finite size effects and formulate the
thermodynamic potential for CFL strangelets. We find that the CFL gap could be
large enough so that the energy per baryon number of CFL strangelets is greatly
affected. In addition, if the quark-quark coupling constant is larger than a
certain critical value, there is a possibility of finding absolutely stable CFL
strangelets.Comment: 7 pages, 3 figures, to appear in Int. J. Mod. Phys.
Is the standard Higgs scalar elementary?
In the standard electroweak model, the measured top quark mass requires a
sizeable Yukawa coupling to the fundamental scalar. This large coupling alone
might induce a dynamical breaking of the electroweak symmetry as well as
non-perturbative effects. If such is the case, even a standard Higgs scalar as
light as 80 GeV should have a non-negligible component induced by
the top condensate.Comment: 8 pages, Latex fil
Postmodern String Theory: Stochastic Formulation
In this paper we study the dynamics of a statistical ensemble of strings,
building on a recently proposed gauge theory of the string geodesic field. We
show that this stochastic approach is equivalent to the Carath\'eodory
formulation of the Nambu-Goto action, supplemented by an averaging procedure
over the family of classical string world-sheets which are solutions of the
equation of motion. In this new framework, the string geodesic field is
reinterpreted as the Gibbs current density associated with the string
statistical ensemble. Next, we show that the classical field equations derived
from the string gauge action, can be obtained as the semi-classical limit of
the string functional wave equation. For closed strings, the wave equation
itself is completely analogous to the Wheeler-DeWitt equation used in quantum
cosmology. Thus, in the string case, the wave function has support on the space
of all possible spatial loop configurations. Finally, we show that the string
distribution induces a multi-phase, or {\it cellular} structure on the
spacetime manifold characterized by domains with a purely Riemannian geometry
separated by domain walls over which there exists a predominantly Weyl
geometry.Comment: 24pages, ReVTe
The back reaction and the effective Einstein's equation for the Universe with ideal fluid cosmological perturbations
We investigate the back reaction of cosmological perturbations on the
evolution of the Universe using the renormalization group method. Starting from
the second order perturbed Einstein's equation, we renormalize a scale factor
of the Universe and derive the evolution equation for the effective scale
factor which includes back reaction due to inhomogeneities of the Universe. The
resulting equation has the same form as the standard Friedman-Robertson-Walker
equation with the effective energy density and pressure which represent the
back reaction effect.Comment: 16 pages, to appear in Phys. Rev.
Z Boson Propagator Correction in Technicolor Theories with ETC Effects Included
We calculate the Z boson propagator correction, as described by the S
parameter, in technicolor theories with extended technicolor interactions
included. Our method is to solve the Bethe-Salpeter equation for the requisite
current-current correlation functions. Our results suggest that the inclusion
of extended technicolor interactions has a relatively small effect on S.Comment: 15pages, 8 figure
Comment on ``Relativistic kinetic equations for electromagnetic, scalar and pseudoscalar interactions''
It is found that the extra quantum constraints to the spinor components of
the equal-time Wigner function given in a recent paper by Zhuang and Heinz
should vanish identically. We point out here the origin of the error and give
an interpretation of the result. However, the principal idea of obtaining a
complete equal-time transport theory by energy averaging the covariant theory
remains valid. The classical transport equation for the spin density is also
found to be incorrect. We give here the correct form of that equation and
discuss briefly its structure.Comment: 5 pages LaTe
Vector field theories in cosmology
Recently proposed theories based on the cosmic presence of a vectorial field
are compared and contrasted. In particular the so called Einstein aether theory
is discussed in parallel with a recent proposal of a strained space-time theory
(Cosmic Defect theory). We show that the latter fits reasonably well the cosmic
observed data with only one, or at most two, adjustable parameters, whilst
other vector theories use much more. The Newtonian limits are also compared.
Finally we show that the CD theory may be considered as a special case of the
aether theories, corresponding to a more compact and consistent paradigm.Comment: 19 pages, 1 figure, to appear on Phys. Rev.
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