4,371 research outputs found
Narratives and Expert Information in Agenda-Setting: Experimental Evidence on State Legislator Engagement with Artificial Intelligence Policy
Are narratives as influential in gaining the attention of policymakers as expert information, including for complex, technical policy domains such as artificial intelligence (AI) policy? This pre-registered study uses a field experiment to evaluate legislator responsiveness to policy entrepreneur outreach. In partnership with a leading AI think tank, we send more than 7300 U.S. state legislative offices emails about AI policy containing an influence strategy (providing a narrative, expert information, or the organization\u27s background), along with a prominent issue frame about AI (emphasizing technological competition or ethical implications). To assess engagement, we measure link clicks to further resources and webinar registration and attendance. Although AI policy is a highly technical domain, we find that narratives are just as effective as expert information in engaging legislators. Compared to control, expert information and narratives led to 28 and 34 percent increases in policymaker engagement, respectively. Furthermore, higher legislature professionalism and lower state-level prior AI experience are associated with greater engagement with both narratives and expert information. Finally, we find that policymakers are equally engaged by an ethical framing of AI policy as they are with an economic one. The findings advance efforts to bridge scholarship on policy narratives, policy entrepreneurship, and agenda-setting
Hydrogen production by photoelectrolytic decomposition of H2O using solar energy
Photoelectrochemical systems for the efficient decomposition of water are discussed. Semiconducting d band oxides which would yield the combination of stability, low electron affinity, and moderate band gap essential for an efficient photoanode are sought. The materials PdO and Fe-xRhxO3 appear most likely. Oxygen evolution yields may also be improved by mediation of high energy oxidizing agents, such as CO3(-). Examination of several p type semiconductors as photocathodes revealed remarkable stability for p-GaAs, and also indicated p-CdTe as a stable H2 photoelectrode. Several potentially economical schemes for photoelectrochemical decomposition of water were examined, including photoelectrochemical diodes and two stage, four photon processes
Neural Network Model for Apparent Deterministic Chaos in Spontaneously Bursting Hippocampal Slices
A neural network model that exhibits stochastic population bursting is
studied by simulation. First return maps of inter-burst intervals exhibit
recurrent unstable periodic orbit (UPO)-like trajectories similar to those
found in experiments on hippocampal slices. Applications of various control
methods and surrogate analysis for UPO-detection also yield results similar to
those of experiments. Our results question the interpretation of the
experimental data as evidence for deterministic chaos and suggest caution in
the use of UPO-based methods for detecting determinism in time-series data.Comment: 4 pages, 5 .eps figures (included), requires psfrag.sty (included
Normalization of Collisional Decoherence: Squaring the Delta Function, and an Independent Cross-Check
We show that when the Hornberger--Sipe calculation of collisional decoherence
is carried out with the squared delta function a delta of energy instead of a
delta of the absolute value of momentum, following a method introduced by
Di\'osi, the corrected formula for the decoherence rate is simply obtained. The
results of Hornberger and Sipe and of Di\'osi are shown to be in agreement. As
an independent cross-check, we calculate the mean squared coordinate diffusion
of a hard sphere implied by the corrected decoherence master equation, and show
that it agrees precisely with the same quantity as calculated by a classical
Brownian motion analysis.Comment: Tex: 14 pages 7/30/06: revisions to introduction, and references
added 9/29/06: further minor revisions and references adde
Atom cooling by non-adiabatic expansion
Motivated by the recent discovery that a reflecting wall moving with a
square-root in time trajectory behaves as a universal stopper of classical
particles regardless of their initial velocities, we compare linear in time and
square-root in time expansions of a box to achieve efficient atom cooling. For
the quantum single-atom wavefunctions studied the square-root in time expansion
presents important advantages: asymptotically it leads to zero average energy
whereas any linear in time (constant box-wall velocity) expansion leaves a
non-zero residual energy, except in the limit of an infinitely slow expansion.
For finite final times and box lengths we set a number of bounds and cooling
principles which again confirm the superior performance of the square-root in
time expansion, even more clearly for increasing excitation of the initial
state. Breakdown of adiabaticity is generally fatal for cooling with the linear
expansion but not so with the square-root expansion.Comment: 4 pages, 4 figure
B\"acklund Transformations of MKdV and Painlev\'e Equations
For there are and actions on the space of solutions of
the first nontrivial equation in the Z_2$ actions on the space of solutions of the standard MKdV equation.
These actions survive scaling reduction, and give rise to transformation groups
for certain (systems of) ODEs, including the second, fourth and fifth
Painlev\'e equations.Comment: 8 pages, plain te
Theory of valley-orbit coupling in a Si/SiGe quantum dot
Electron states are studied for quantum dots in a strained Si quantum well,
taking into account both valley and orbital physics. Realistic geometries are
considered, including circular and elliptical dot shapes, parallel and
perpendicular magnetic fields, and (most importantly for valley coupling) the
small local tilt of the quantum well interface away from the crystallographic
axes. In absence of a tilt, valley splitting occurs only between pairs of
states with the same orbital quantum numbers. However, tilting is ubiquitous in
conventional silicon heterostructures, leading to valley-orbit coupling. In
this context, "valley splitting" is no longer a well defined concept, and the
quantity of merit for qubit applications becomes the ground state gap. For
typical dots used as qubits, a rich energy spectrum emerges, as a function of
magnetic field, tilt angle, and orbital quantum number. Numerical and
analytical solutions are obtained for the ground state gap and for the mixing
fraction between the ground and excited states. This mixing can lead to valley
scattering, decoherence, and leakage for Si spin qubits.Comment: 18 pages, including 4 figure
WKB formalism and a lower limit for the energy eigenstates of bound states for some potentials
In the present work the conditions appearing in the WKB approximation
formalism of quantum mechanics are analyzed. It is shown that, in general, a
careful definition of an approximation method requires the introduction of two
length parameters, one of them always considered in the text books on quantum
mechanics, whereas the second one is usually neglected. Afterwards we define a
particular family of potentials and prove, resorting to the aforementioned
length parameters, that we may find an energy which is a lower bound to the
ground energy of the system. The idea is applied to the case of a harmonic
oscillator and also to a particle freely falling in a homogeneous gravitational
field, and in both cases the consistency of our method is corroborated. This
approach, together with the Rayleigh--Ritz formalism, allows us to define an
energy interval in which the ground energy of any potential, belonging to our
family, must lie.Comment: Accepted in Modern Physics Letters
- …