3,835 research outputs found
Silicon-based organic light-emitting diode operating at a wavelength of 1.5 mu m
Copyright 2000 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This article appeared in Applied Physics Letters 77, 2271 (2000) and may be found at
The interminable issue of effectiveness: substantive purposes, outcomes and research challenges in the advancement of environmental impact assessment theory
Concentration dependent interdiffusion in InGaAs/GaAs as evidenced by high resolution x-ray diffraction and photoluminescence spectroscopy
Article copyright 2005 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The article appeared in Journal of Applied Physics 97, 013536 (2005) and may be found at
Fast tuneable InGaAsP DBR laser using quantum-confined stark-effect-induced refractive index change
We report a monolithically integrated InGaAsP DBR ridge waveguide laser that uses the quantum-confined Stark effect (QCSE) to achieve fast tuning response. The laser incorporates three sections: a forward-biased gain section, a reverse-biased phase section, and a reverse-biased DBR tuning section. The laser behavior is modeled using transmission matrix equations and tuning over similar to 8 nm is predicted. Devices were fabricated using post-growth shallow ion implantation to reduce the loss in the phase and DBR sections by quantum well intermixing. The lasing wavelength was measured while varying the reverse bias of the phase and DBR sections in the range 0 V to < - 2.5 V. Timing was noncontinuous over a similar to 7-nm-wavelength range, with a side-mode suppression ratio of similar to 20 dB. Coupled cavity effects due to the fabrication method used introduced discontinuities in tuning. The frequency modulation (FM) response was measured to be uniform within 2 dB over the frequency range 10 MHz to 10 GHz, indicating that tuning times of 100 ps are possible
The holomorphic bosonic string
We present a holomorphic version of the bosonic string in the formalism of
quantum field theory developed by Costello and collaborators. In this paper we
focus on the case in which space-time is flat and construct a one-loop exact
quantization. Starting from first principles, we arrive at the critical
dimension as an obstruction to satisfying the quantum master equation.
Moreover, we show how the factorization algebra recovers the BRST cohomology of
the string and give another construction of the Gerstenhaber structure.
Finally, we show how the factorization homology along closed manifolds encodes
the determinant line bundle over the moduli space of Riemann surfaces.Comment: Fixed typos and clarified exposition. Modified Section
A one-loop exact quantization of Chern-Simons theory
We examine Chern-Simons theory as a deformation of a 3-dimensional BF theory
that is partially holomorphic and partially topological. In particular, we
introduce a novel gauge that leads naturally to a one-loop exact quantization
of this BF theory and Chern-Simons theory. This approach illuminates several
important features of Chern-Simons theory, notably the bulk-boundary
correspondence of Chern-Simons theory with chiral WZW theory. In addition to
rigorously constructing the theory, we also explain how it applies to a large
class of closely related 3-dimensional theories and some of the consequences
for factorization algebras of observables.Comment: 35 pages, 1 figur
Higher Kac-Moody algebras and symmetries of holomorphic field theories
We introduce a higher dimensional generalization of the affine Kac-Moody
algebra using the language of factorization algebras. In particular, on any
complex manifold there is a factorization algebra of "currents" associated to
any Lie algebra. We classify local cocycles of these current algebras, and
compare them to central extensions of higher affine algebras recently proposed
by Faonte-Hennion-Kapranov. A central goal of this paper is to witness higher
Kac-Moody algebras as symmetries of a class of holomorphic quantum field
theories. In particular, we prove a generalization of the free field
realization of an affine Kac-Moody algebra and also develop the theory of
q-characters for this class of algebras in terms of factorization homology.
Finally, we exhibit the "large N" behavior of higher Kac-Moody algebras and
their relationship to symmetries of non-commutative field theories.Comment: All around improvements to exposition. Added Section 5: Large N
Limit
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