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Hold-up and the evolution of investment and bargaining norms
The purpose of this paper is to explore the evolution of bargaining norms in a simple team production problem with two sided relationship specific investments, and competition. The puzzle we wish to address is why efficient bargaining norms do not evolve even though there exist efficient sequential equilibria. Conditions under which stochastically stable bargaining conventions exist are characterized, and it is shown that the stochastically stable division rule is independent of the long run investment strategy. Hence, efficient sequential equilibria are not in general stochastically stable, a result that may help us understand why institutions, such as firms, may be needed to ensure efficient exchange in the context of relationship specific investments. We also find that increasing competition, while enhancing incentives, may also destabilize existing bargaining norms
Automated detection of laser cooling schemes for ultracold molecules
One of the demanding frontiers in ultracold science is identifying laser
cooling schemes for complex atoms and molecules, out of their vast spectra of
internal states. Motivated by a need to expand the set of available ultracold
molecules for applications in fundamental physics, chemistry, astrochemistry,
and quantum simulation, we propose and demonstrate an automated graph-based
search approach for viable laser cooling schemes. The method is time efficient
and the outcomes greatly surpass the results of manual searches used so far. We
discover new laser cooling schemes for C, OH, CN, YO, and CO that
can be viewed as surprising or counterintuitive compared to previously
identified laser cooling schemes. In addition, a central insight of this work
is that the reinterpretation of quantum states and transitions between them as
a graph can dramatically enhance our ability to identify new quantum control
schemes for complex quantum systems. As such, this approach will also be
applicable to complex atoms and, in fact, any complex many-body quantum system
with a discrete spectrum of internal states.Comment: 10 pages and 5 figures in the main text + 11 pages and 7 figures in
appendices. Comments and feedback are very welcome. Code is available at
https://github.com/Shmoo137/Detection-Of-Laser-Cooled-Molecule
On the Equivalence of Three-Particle Scattering Formalisms
In recent years, different on-shell scattering
formalisms have been proposed to be applied to both lattice QCD and infinite
volume scattering processes. We prove that the formulation in the infinite
volume presented by Hansen and Sharpe in Phys.~Rev.~D92, 114509 (2015) and
subsequently Brice\~no, Hansen, and Sharpe in Phys.~Rev.~D95, 074510 (2017) can
be recovered from the -matrix representation, derived on the basis of
-matrix unitarity, presented by Mai {\em et al.} in Eur.~Phys.~J.~A53, 177
(2017) and Jackura {\em et al.} in Eur.~Phys.~J.~C79, 56 (2019). Therefore,
both formalisms in the infinite volume are equivalent and the physical content
is identical. Additionally, the Faddeev equations are recovered in the
non-relativistic limit of both representations.Comment: 13 pages, 5 figure
Evolution of Efimov States
The Efimov phenomenon manifests itself as an emergent discrete scaling
symmetry in the quantum three-body problem. In the unitarity limit, it leads to
an infinite tower of three-body bound states with energies forming a geometric
sequence. In this work, we study the evolution of these so-called Efimov states
using relativistic scattering theory. We identify them as poles of the
three-particle matrix and trace their trajectories in the complex energy
plane as they evolve from virtual states through bound states to resonances. We
dial the scattering parameters toward the unitarity limit and observe the
emergence of the universal scaling of energies and couplings -- a behavior
known from the non-relativistic case. Interestingly, we find that Efimov
resonances follow unusual, cyclic trajectories accumulating at the three-body
threshold and then disappear at some values of the two-body scattering length.
We propose a partial resolution to this "missing states" problem.Comment: 15 pages, 10 figures
Solving relativistic three-body integral equations in the presence of bound states
We present a systematically improvable method for numerically solving
relativistic three-body integral equations for the partial-wave projected
amplitudes. The method consists of a discretization procedure in momentum
space, which approximates the continuum problem with a matrix equation. It is
solved for different matrix sizes, and in the end, an extrapolation is employed
to restore the continuum limit. Our technique is tested by solving a three-body
problem of scalar particles with an wave two-body bound state. We discuss
two methods of incorporating the pole contribution in the integral equations,
both of them leading to agreement with previous results obtained using
finite-volume spectra of the same theory. We provide an analytic and numerical
estimate of the systematic errors. Although we focus on kinematics below the
three-particle threshold, we provide numerical evidence that the methods
presented allow for determination of amplitude above this threshold as well.Comment: 20 pages, 9 figure
Solving Relativistic Three-Body Integral Equations in the Presence of Bound States
We present a simple scheme for solving relativistic integral equations for the partial-wave projected three-body amplitudes. Our techniques are used to solve a problem of three scalar particles with a formation of a S-wave two-body bound state. We rewrite the problem in a form suitable for numerical solution and then explore three solving strategies. In particular, we discuss different ways of incorporating the bound-state pole contribution in the integral equations. All of them lead to agreement with previous results obtained using finite-volume spectra of the same theory, providing further evidence of the validity of the existing finite- and infinite-volume formalism for studying three-particle systems. We discuss an analytic and numerical estimate of the systematic errors and provide numerical evidence that the methods presented allow for determination of amplitude above the three-body threshold as well. In conjunction with the previously derived finite-volume formalism, this work furthers the objective for extracting three-hadron scattering amplitudes directly from lattice QCD
The influence of nano-architectured CeOx supports in RhPd/CeO2 for the catalytic ethanol steam reforming reaction
The ethanol steam reforming (ESR) reaction has been tested over RhPd supported on polycrystalline ceria in comparison to structured supports composed of nanoshaped CeO2 cubes and CeO2 rods tailored toward the production of hydrogen. At 650-700 K the hydrogen yield follows the trend RhPd/CeO(2)cubes >RhPd/CeO2-rods >RhPd/CeO2-polycrystalline, whereas at temperatures higher than 800K the catalytic performance of all samples is similar and close to the thermodynamic equilibrium. The improved performance of RhPd/CeO2-cubes and RhPd/CeO2-rods for ESR at low temperature is mainly ascribed to higher water-gas shift activity and a strong interaction between the bimetallic-oxide support interaction. STEM analysis shows the existence of RhPd alloyed nanoparticles in all samples, with no apparent relationship between ESR performance and RhPd particle size. X-ray diffraction under operating conditions shows metal reorganization on {1 0 0} and {1 1 0} ceria crystallographic planes during catalyst activation and ESR, but not on {1 1 1} ceria crystallographic planes. The RhPd reconstructing and tuned activation over ceria nanocubes and nanorods is considered the main reason for better catalytic activity with respect to conventional catalysts based on polycrystalline ceria. (C) 2015 Elsevier B.V. All rights reserved.Postprint (author's final draft
Spatial interactions in agent-based modeling
Agent Based Modeling (ABM) has become a widespread approach to model complex
interactions. In this chapter after briefly summarizing some features of ABM
the different approaches in modeling spatial interactions are discussed.
It is stressed that agents can interact either indirectly through a shared
environment and/or directly with each other. In such an approach, higher-order
variables such as commodity prices, population dynamics or even institutions,
are not exogenously specified but instead are seen as the results of
interactions. It is highlighted in the chapter that the understanding of
patterns emerging from such spatial interaction between agents is a key problem
as much as their description through analytical or simulation means.
The chapter reviews different approaches for modeling agents' behavior,
taking into account either explicit spatial (lattice based) structures or
networks. Some emphasis is placed on recent ABM as applied to the description
of the dynamics of the geographical distribution of economic activities, - out
of equilibrium. The Eurace@Unibi Model, an agent-based macroeconomic model with
spatial structure, is used to illustrate the potential of such an approach for
spatial policy analysis.Comment: 26 pages, 5 figures, 105 references; a chapter prepared for the book
"Complexity and Geographical Economics - Topics and Tools", P. Commendatore,
S.S. Kayam and I. Kubin, Eds. (Springer, in press, 2014
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