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

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