6,727 research outputs found
Gutzwiller Monte Carlo approach for a critical dissipative spin model
We use the Gutzwiller Monte Carlo approach to simulate the dissipative
XYZ-model in the vicinity of a dissipative phase transition. This approach
captures classical spatial correlations together with the full on-site quantum
behavior, while neglecting non-local quantum effects. By considering finite
two-dimensional lattices of various sizes, we identify a ferromagnetic and two
paramagnetic phases, in agreement with earlier studies. The greatly reduced
numerical complexity the Gutzwiller Monte Carlo approach facilitates efficient
simulation of relatively large lattice sizes. The inclusion of the spatial
correlations allows to describe critical behavior which is completely missed by
the widely applied Gutzwiller decoupling of the density matrix
Why did Alaska eliminate the Alaska Coastal Management Program?
Thesis (M.S.) University of Alaska Fairbanks, 2018In 1972, the federal government passed the Coastal Zone Management Act. The federal government recognized that there is a national interest in effective management of the nation's coasts. The act created a program that made it possible for states to collaborate with the federal government to manage the nation's coastal areas and resources. In July of 2011, after thirty-two years of active participation in the program, Alaska became the only eligible state or territory to choose to no longer take part in the program. This action significantly affected Alaska's ability to manage the state's coastline and resources. This research is a qualitative case study that documents the events leading up to the establishment of the Alaska Coastal Management Program, its implementation, its elimination, and the initiative regarding its possible reinstatement. The research evaluates the current form of Alaska's coastal management practices to determine if it meets Elinor Ostrom's design principles for effective common property resource management, as well as theories on decentralization/devolution, polycentric governance, and adaptability and resilience. The research concludes that Alaska's choice to eliminate the Alaska Coastal Management Program was influenced by the interests of natural resource extraction agencies and a consequence of divisive party politics. The research finds that the effect of eliminating the Alaska Coastal Management Program was that the State of Alaska took a significant step away from what science recommends as prudent ways to manage common property resources
Critical superfluid velocity in a trapped dipolar gas
We investigate the superfluid properties of a dipolar Bose-Einstein
condensate (BEC) in a fully three-dimensional trap. Specifically, we calculate
a superfluid critical velocity for this system by applying the Landau criterion
to its discrete quasiparticle spectrum. We test this critical velocity by
direct numerical simulation of condensate depletion as a blue-detuned laser
moves through the condensate. In both cases, the presence of the roton in the
spectrum serves to lower the critical velocity beyond a critical particle
number. Since the shape of the dispersion, and hence the roton minimum, is
tunable as a function of particle number, we thereby propose an experiment that
can simultaneously measure the Landau critical velocity of a dipolar BEC and
demonstrate the presence of the roton in this system.Comment: 5 pages, 4 figures, version accepted to PR
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Power-Ups in Digital Games: The Rewarding Effect of Phantom Game Elementson Player Experience
Power-ups are a type of game reward that allow the player tocustomise their experience by altering gameplay for a shortperiod of time. Despite the wide use of power-ups in videogames, little is known about their effect on gaming experiences.To explore this, we conducted an experimental study that compares the experiences of players depending on their exposureto power-ups in a recreational video game. The results show that players who collected power-ups felt significantly more immersed in the game, experienced more autonomy, but didnot feel more competent or challenged than those who played the game without these collectables. Interestingly, a similareffect was observed for those players who picked up ‘placebo ’power-ups, despite the items having no effect on the gameplay. We provide a discussion of these results and their implications both for games user researchers and game designers
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