711 research outputs found
Evolutionary Game Dynamics for Two Interacting Populations under Environmental Feedback
We study the evolutionary dynamics of games under environmental feedback
using replicator equations for two interacting populations. One key feature is
to consider jointly the co-evolution of the dynamic payoff matrices and the
state of the environment: the payoff matrix varies with the changing
environment and at the same time, the state of the environment is affected
indirectly by the changing payoff matrix through the evolving population
profiles. For such co-evolutionary dynamics, we investigate whether convergence
will take place, and if so, how. In particular, we identify the scenarios where
oscillation offers the best predictions of long-run behavior by using
reversible system theory. The obtained results are useful to describe the
evolution of multi-community societies in which individuals' payoffs and
societal feedback interact.Comment: 7 pages, submitted to a conferenc
Limit Cycles in Replicator-Mutator Dynamics with Game-Environment Feedback
This paper considers the coevolutionary game and environment dynamics under mutations of strategies. Individuals’ game play affects the dynamics of changing environments while the environment in turn affects the decision-making dynamics of individuals through modulating game payoffs. For some such closed-loop systems, we prove that limit cycles will never appear; however, in sharp contrast, after allowing mutations of strategies in these systems, the resulting replicator-mutator dynamics under environmental feedback may well exhibit Hopf bifurcation and limit cycles. We prove conditions for the Hopf bifurcation and thus the existence of stable limit cycles, and also illustrate these results using simulations. For the coevolutionary game and environment system, these stable limit cycles correspond to sustained oscillations of population’s decisions and richness of the environmental resource
Entanglement dynamics of photon pairs emitted from quantum dot
We present a model to derive the state of the photon pairs generated by the
biexciton cascade decay of a self-assembled quantum dot, which agrees well with
the experimental result. Furthermore we calculate the concurrence and
entanglement sudden death is found in this system with temperature increasing,
which prevents quantum dot emits entangled photon pairs at a high temperature.
The relationship between the fine structure splitting and the sudden death
temperature is provided too
Limit cycles analysis and control of evolutionary game dynamics with environmental feedback
Recently, an evolutionary game dynamics model taking into account the environmental feedback has been proposed to describe the co-evolution of strategic actions of a population of individuals and the state of the surrounding environment; correspondingly a range of interesting dynamic behaviors have been reported. In this paper, we provide new theoretical insight into such behaviors and discuss control options. Instead of the standard replicator dynamics, we use a more realistic and comprehensive model of replicator–mutator dynamics, to describe the strategic evolution of the population. After integrating the environment feedback, we study the effect of mutations on the resulting closed-loop system dynamics. We prove the conditions for two types of bifurcations, Hopf bifurcation and Heteroclinic bifurcation, both of which result in stable limit cycles. These limit cycles have not been identified in existing works, and we further prove that such limit cycles are in fact persistent in a large parameter space and are almost globally stable. In the end, an intuitive control policy based on incentives is applied, and the effectiveness of this control policy is examined by analysis and simulations
Strange and Charm Quark Spins from Anomalous Ward Identity
We present a calculation of the strange and charm quark contributions to the
nucleon spin from the anomalous Ward identity (AWI). It is performed with
overlap valence quarks on 2+1-flavor domain-wall fermion gauge configurations
on a lattice with the light sea mass at MeV.
To satisfy the AWI, the overlap fermion for the pseudoscalar density and the
overlap Dirac operator for the topological density, which do not have
multiplicative renormalization, are used to normalize the form factor of the
local axial-vector current at finite . For the charm quark, we find that
the negative pseudoscalar term almost cancels the positive topological term.
For the strange quark, the pseudoscalar term is less negative than that of the
charm. By imposing the AWI, the strange at is obtained by a
global fit of the pseudoscalar and the topological form factors, together with
and the induced pseudoscalar form factor at finite .
The chiral extrapolation to the physical pion mass gives .Comment: 8 pages, 9 figures. Updated version where a sign error is correcte
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