1,866 research outputs found
A histogram-free multicanonical Monte Carlo algorithm for the basis expansion of density of states
We report a new multicanonical Monte Carlo (MC) algorithm to obtain the
density of states (DOS) for physical systems with continuous state variables in
statistical mechanics. Our algorithm is able to obtain an analytical form for
the DOS expressed in a chosen basis set, instead of a numerical array of finite
resolution as in previous variants of this class of MC methods such as the
multicanonical (MUCA) sampling and Wang-Landau (WL) sampling. This is enabled
by storing the visited states directly in a data set and avoiding the explicit
collection of a histogram. This practice also has the advantage of avoiding
undesirable artificial errors caused by the discretization and binning of
continuous state variables. Our results show that this scheme is capable of
obtaining converged results with a much reduced number of Monte Carlo steps,
leading to a significant speedup over existing algorithms.Comment: 8 pages, 6 figures. Paper accepted in the Platform for Advanced
Scientific Computing Conference (PASC '17), June 26 to 28, 2017, Lugano,
Switzerlan
Regis-Darwin specified in the p-Calculus
There now is a translator for DARWIN programs that automatically generates their π-calculus equivalents. A variety of errors in DARWIN programs can be detected at the π-calculus level. These include detection of recursive structures, unbound ports and ports that are bound in the wrong direction. It can also be used to confirm whether two REGIS-DARWIN programs are equivalent
Correspondence between many-particle excitations and the entanglement spectrum of disordered ballistic one-dimensional systems
Using exact diagonalization for non-interacting systems and density matrix
renormalization group for interacting systems we show that Li and Haldane's
conjecture on the correspondence between the low-lying many-particle excitation
spectrum and the entanglement spectrum holds for disordered ballistic
one-dimensional many-particle systems. In order to demonstrate the
correspondence we develop a computational efficient way to calculate the ES of
low-excitation of non-interacting systems. We observe and explain the presence
of an unexpected shell structure in the excitation structure. The low-lying
shell are robust and survive even for strong electron-electron interactions.Comment: 6 pages 4 figure
A flexible model for dynamic linking in Java and C#
Dynamic linking supports flexible code deployment, allowing partially linked code to link further code on the fly, as needed.
Thus, end-users enjoy the advantage of automatically receiving any updates, without any need for any explicit actions on their side,
such as re-compilation, or re-linking. On the down side, two executions of a program may link in different versions of code, which
in some cases causes subtle errors, and may mystify end-users.
Dynamic linking in Java and C# are similar: the same linking phases are involved, soundness is based on similar ideas, and
executions which do not throw linking errors give the same result. They are, however, not identical: the linking phases are combined
differently, and take place in different order. Consequently, linking errors may be detected at different times by Java and C# runtime
systems.
We develop a non-deterministic model, which describes the behaviour of both Java and C# program executions. The nondeterminism
allows us to describe the design space, to distill the similarities between the two languages, and to use one proof of
soundness for both. We also prove that all execution strategies are equivalent with respect to terminating executions that do not
throw link errors: they give the same results
Finding a Balance: A Narrative Inquiry into Motherhood and the Doctoral Process
Carolyn Ellis states, “autoethnography shows struggle, passion, embodied life, and the collaborative creation of sense - making... [it] wants the reader to care, to feel, to empathize, and to do something, to act” (Ellis & Bochner, 2006, p. 433). This autoethnography describes one new mother’s struggles to complete her doctoral program of study while remaining devoted to her familial obligations and relationships. In particular, this article investigates the causes of tension and stress that exist as she attempts to find a balance between her need to care and love for her child, to maintain a relationship with her husband, and achieve success within her graduate studies. Using autoethnography, the author makes herself vulnerable as she shares her intimate experiences through personal journal entries and stories of encounters with family and friends. In this way, the author hopes to utilize her personal experience in an effort to open dialogue concerning the diverse needs of today’s graduate student mothers as they attempt to successfully earn a graduate degree
Synthetic Chemotaxis and Collective Behavior in Active Matter
Conspectus: The ability to navigate in chemical gradients, called chemotaxis,
is crucial for the survival of microorganisms. It allows them to find food and
to escape from toxins. Many microorganisms can produce the chemicals to which
they respond themselves and use chemotaxis for signalling which can be seen as
a basic form of communication. Remarkably, the past decade has let to the
development of synthetic microswimmers like e.g. autophoretic Janus colloids,
which can self-propel through a solvent, analogously to bacteria and other
microorganims. The mechanism underlying their self-propulsion involves the
production of certain chemicals. The same chemicals involved in the
self-propulsion mechanism also act on other microswimmers and bias their
swimming direction towards (or away from) the producing microswimmer. Synthetic
microswimmers therefore provide a synthetic analogue to chemotactic motile
microorganisms. When these interactions are attractive, they commonly lead to
clusters, even at low particle density. These clusters may either proceed
towards macrophase separation, resembling Dictyostelium aggregation, or, as
shown very recently, lead to dynamic clusters of self-limited size (dynamic
clustering) as seen in experiments in autophoretic Janus colloids. Besides the
classical case where chemical interactions are attractive, this Account
discusses, as its main focus, repulsive chemical interactions, which can create
a new and less known avenue to pattern formation in active systems leading to a
variety of pattern, including clusters which are surrounded by shells of
chemicals, travelling waves and more complex continously reshaping patterns. In
all these cases `synthetic signalling' can crucially determine the collective
behavior of synthetic microswimmer ensembles and can be used as a design
principle to create patterns in motile active particles
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