2,282 research outputs found
Polariton Squeezing in Semiconductor Microcavities
We report squeezed polariton generation using parametric polariton four-wave
mixing in semiconductor microcavities in the strong coupling regime. The
geometry of the experiment corresponds to degenerate four-wave mixing, which
gives rise to a bistability threshold. Spatial effects in the nonlinear regime
are evidenced, and spatial filtering is required in order to optimize the
measured squeezing. By measuring the noise of the outgoing light, we infer a 9
percent squeezing on the polariton field close to the bistability turning
point
Synthesis for Polynomial Lasso Programs
We present a method for the synthesis of polynomial lasso programs. These
programs consist of a program stem, a set of transitions, and an exit
condition, all in the form of algebraic assertions (conjunctions of polynomial
equalities). Central to this approach is the discovery of non-linear
(algebraic) loop invariants. We extend Sankaranarayanan, Sipma, and Manna's
template-based approach and prove a completeness criterion. We perform program
synthesis by generating a constraint whose solution is a synthesized program
together with a loop invariant that proves the program's correctness. This
constraint is non-linear and is passed to an SMT solver. Moreover, we can
enforce the termination of the synthesized program with the support of test
cases.Comment: Paper at VMCAI'14, including appendi
Numerical approach to the Schrodinger equation in momentum space
The treatment of the time-independent Schrodinger equation in real-space is
an indispensable part of introductory quantum mechanics. In contrast, the
Schrodinger equation in momentum space is an integral equation that is not
readily amenable to an analytical solution and is rarely taught. We present a
numerical approach to the Schrodinger equation in momentum space. After a
suitable discretization process, we obtain the Hamiltonian matrix and
diagonalize it numerically. By considering a few examples, we show that this
approach is ideal for exploring bound-states in a localized potential and
complements the traditional (analytical or numerical) treatment of the
Schrodinger equation in real-space.Comment: 14 pages, 4 figures, several changes and one figure correctio
A mid-infrared survey of the inner 2 Ă— 1.5 degrees of the Galaxy with Spitzer/IRAC
We present a survey of Spitzer Space Telescope/IRAC observations of the central 2 Ă— 1.5 degrees (265 Ă— 200 pc) of the Galaxy at 3-8 ÎĽm. These data represent the highest spatial resolution and sensitivity large-scale map made to date of the Galactic Center (GC) at mid-infrared wavelengths. The IRAC data provide a census of the optically obscured stellar sources as well as a detailed map of the highly filamentary structure in the interstellar medium. The diffuse emission is dominated by PAH emission from small grains in star-forming regions. Dark clouds displaying a large variety of sizes and morphologies are imaged, many of which remain opaque at IRAC wavelengths. Using a multiwavelength comparison, we determine which objects are likely to be in the foreground and which are located at the GC. We find no counterparts at IRAC wavelengths to the unique system of linear, nonthermal radio filaments present at the GC
Dynamic Obstacle Avoidance
Report on the methodology and results of experimental software development in order to produce an efficient and effective mechanism whereby entities controlled by computer generated forces systems can avoid collisions with other moving entities within a distributed interactive simulation environment
The Effects of Postfire Salvage Logging on Aquatic Ecosystems in the American West
Recent changes in the forest policies, regulations, and laws affecting public lands encourage postfire salvage logging, an activity that all too often delays or prevents recovery. In contrast, the 10 recommendations proposed here can improve the condition of watersheds and aquatic ecosystems
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