4,874 research outputs found
Universal Quantum Computation by Scattering in the Fermi-Hubbard Model
The Hubbard model may be the simplest model of particles interacting on a
lattice, but simulation of its dynamics remains beyond the reach of current
numerical methods. In this article, we show that general quantum computations
can be encoded into the physics of wave packets propagating through a planar
graph, with scattering interactions governed by the fermionic Hubbard model.
Therefore, simulating the model on planar graphs is as hard as simulating
quantum computation. We give two different arguments, demonstrating that the
simulation is difficult both for wave packets prepared as excitations of the
fermionic vacuum, and for hole wave packets at filling fraction one-half in the
limit of strong coupling. In the latter case, which is described by the t-J
model, there is only reflection and no transmission in the scattering events,
as would be the case for classical hard spheres. In that sense, the
construction provides a quantum mechanical analog of the Fredkin-Toffoli
billiard ball computer.Comment: 9 pages, 5 figures. Hyperref and cleveref LaTeX packages conflicted
(fixed by including hyperref before cleveref). Other minor edit
STEWARDSHIP IN WEST AFRICAN VODUN: A CASE STUDY OF OUIDAH, BENIN
Indigenous, animistic religions inherently convey a close relationship and stewardship for the environment. This stewardship is very apparent in the region of southern Benin, Africa. The Fon peoples of this region practice a traditional religion termed Vodun, which manifested from the 17th century slave trade, and subsequently migrated to the Caribbean and Americas where it transmuted into Voodoo, among other religions. The migration of pre-colonial religious canon to the Western Hemisphere has garnered ample study; however, the pioneering religion, Vodun, has received far less scholastic attention, despite Benin’s recognition of Vodun as a national religion. In this thesis, I contend that the Fon exemplify a society that incorporates rites and rituals of their animistic religion into their daily lives expressed through forms of stewardship, particularly as it pertains to the Forêt Sacrée de Kpassé. This fusion of religious tradition with environmental interaction is inseparable, as are the subsequent environmental effects. This thesis discussion entails an investigation of the impacts of Vodun beliefs on environment-society relations. The results of this study are based upon a qualitative study conducted in the summer of 2009 in Ouidah, Benin
Holographic duality from random tensor networks
Tensor networks provide a natural framework for exploring holographic duality
because they obey entanglement area laws. They have been used to construct
explicit toy models realizing many interesting structural features of the
AdS/CFT correspondence, including the non-uniqueness of bulk operator
reconstruction in the boundary theory. In this article, we explore the
holographic properties of networks of random tensors. We find that our models
naturally incorporate many features that are analogous to those of the AdS/CFT
correspondence. When the bond dimension of the tensors is large, we show that
the entanglement entropy of boundary regions, whether connected or not, obey
the Ryu-Takayanagi entropy formula, a fact closely related to known properties
of the multipartite entanglement of assistance. Moreover, we find that each
boundary region faithfully encodes the physics of the entire bulk entanglement
wedge. Our method is to interpret the average over random tensors as the
partition function of a classical ferromagnetic Ising model, so that the
minimal surfaces of Ryu-Takayanagi appear as domain walls. Upon including the
analog of a bulk field, we find that our model reproduces the expected
corrections to the Ryu-Takayanagi formula: the minimal surface is displaced and
the entropy is augmented by the entanglement of the bulk field. Increasing the
entanglement of the bulk field ultimately changes the minimal surface
topologically in a way similar to creation of a black hole. Extrapolating bulk
correlation functions to the boundary permits the calculation of the scaling
dimensions of boundary operators, which exhibit a large gap between a small
number of low-dimension operators and the rest. While we are primarily
motivated by AdS/CFT duality, our main results define a more general form of
bulk-boundary correspondence which could be useful for extending holography to
other spacetimes.Comment: 57 pages, 13 figure
Group T ASME DESIGN CHALLENGE PROJECT
Design and build a RC Robot eligible to compete in the 2019 ASME Challenge, the Pick-and-Place Rac
JUSTICE REED AND THE FIRST AMENDMENT-THE RELIGION CLAUSES. By F. William O\u27Brien, S.J. – A TREATISE ON THE LAW OF CONTRACTS BY SAMUEL WILLISTON. (Third edition by Walter H. E. Jaeger).
Mating tactics of male feral goats ( Capra hircus ): risks and benefits
Intense competition between males for reproduction has led to the evolution of alternative mating tactics (AMTs). Feral goat males usually use a tactic called tending, in which they defend oestrous females from other males. Males may also use a second mating tactic called coursing, in which they gain access to oestrous females by disturbing a tending pair. Herein, we examine estimated mating success (EMS) and risks of using these tactics. Tending was only used by mature (≥4 years old), higher-ranking males and accounted for 75% of EMS. Coursing was used by males of all ages and dominance ranks, and accounted for 25% of EMS. Using coursing, male kids achieved 8% of EMS. Mature males achieved 92% of EMS. Both age and dominance rank were related to EMS, but age was not important after its relationship with dominance was controlled. Tending bouts were, on average, ca. 30min long, while coursing bouts only averaged ca. 2min. Males were more likely to suffer a butt while coursing than while tending, and formerly tending males were responsible for most butts. Kids that coursed had the highest risk of being butted. In most AMTs, there are reductions in the risks in relation to low fitness benefits. However, we found that the risks of butts during coursing were high, while our evidence suggests that the EMS was probably low. Nevertheless, the existence of an effective AMT in male feral goats may have an important influence on the intensity of sexual selection and the effective population siz
Fallow deer polyandry is related to fertilization insurance
Polyandry is widespread, but its adaptive significance is not fully understood. The hypotheses used to explain its persistence have rarely been tested in the wild and particularly for large, long-lived mammals. We investigated polyandry in fallow deer, using female mating and reproduction data gathered over 10years. Females of this species produce a single offspring (monotocous) and can live to 23years old. Overall, polyandry was evident in 12% of females and the long-term, consistent proportion of polyandrous females observed, suggests that monandry and polyandry represent alternative mating strategies. Females were more likely to be polyandrous when their first mate had previously achieved high numbers of matings during the rut or was relatively old. However, polyandry was not related to the following factors: female age, the stage of the rut, the dominance ranks of mates, or the number of daily matings achieved by males. Polyandrous and monandrous multiple-mating females were not more likely than single-mating females to be observed with an offspring during the following year, and there were no significant differences in offspring size between these females. These results provide support for a fertility insurance hypothesis, with females remating if fertilization from the first mating was uncertain due to possible sperm depletion. The potential for different female mating strategies among large, polygynous mammals has generally been overlooked. Our findings highlight the complexity of female reproductive strategies and the possible trade-offs between fertilization success, preferences for high-quality males, and potential costs of polyandry, particularly for monotocous specie
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