2,768 research outputs found
Deconfinement transition and dimensional cross-over in the 3D gauge Ising model
We present a high precision Monte Carlo study of the finite temperature
gauge theory in 2+1 dimensions. The duality with the 3D Ising spin model allows
us to use powerful cluster algorithms for the simulations. For temporal
extensions up to we obtain the inverse critical temperature with a
statistical accuracy comparable with the most accurate results for the bulk
phase transition of the 3D Ising model. We discuss the predictions of T. W.
Capehart and M.E. Fisher for the dimensional crossover from 2 to 3 dimensions.
Our precise data for the critical exponents and critical amplitudes confirm the
Svetitsky-Yaffe conjecture. We find deviations from Olesen's prediction for the
critical temperature of about 20%.Comment: latex file of 21 pages plus 1 ps figure. Minor corrections in the
figure. Text unchange
Pulsar data analysis with PSRCHIVE
PSRCHIVE is an open-source, object-oriented, scientific data analysis
software library and application suite for pulsar astronomy. It implements an
extensive range of general-purpose algorithms for use in data calibration and
integration, statistical analysis and modeling, and visualisation. These are
utilised by a variety of applications specialised for tasks such as pulsar
timing, polarimetry, radio frequency interference mitigation, and pulse
variability studies. This paper presents a general overview of PSRCHIVE
functionality with some focus on the integrated interfaces developed for the
core applications.Comment: 21 pages, 5 figures; tutorial presented at IPTA 2010 meeting in
Leiden merged with talk presented at 2011 pulsar conference in Beijing;
includes further research and development on algorithms for RFI mitigation
and TOA bias correctio
Surface tension and interfacial fluctuations in d-dimensional Ising model
The surface tension of rough interfaces between coexisting phases in 2D and
3D Ising models are discussed in view of the known results and some original
calculations presented in this paper. The results are summarised in a formula,
which allows to interpolate the corrections to finite-size scaling between two
and three dimensions. The physical meaning of an analytic continuation to
noninteger values of the spatial dimensionality d is discussed. Lattices and
interfaces with properly defined fractal dimensions should fulfil certain
requirements to possibly have properties of an analytic continuation from
d-dimensional hypercubes. Here 2 appears as the marginal value of d below which
the (d-1)-dimensional interface splits in disconnected pieces. Some
phenomenological arguments are proposed to describe such interfaces. They show
that the character of the interfacial fluctuations at d<2 is not the same as
provided by a formal analytic continuation from d-dimensional hypercubes with d
>= 2. It, probably, is true also for the related critical exponents.Comment: 10 pages, no figures. In the second version changes are made to make
it consistent with the published paper (Sec.2 is completed
Predictable arguments of knowledge
We initiate a formal investigation on the power of predictability for argument of knowledge systems for NP. Specifically, we consider private-coin argument systems where the answer of the prover can be predicted, given the private randomness of the verifier; we call such protocols Predictable Arguments of Knowledge (PAoK).
Our study encompasses a full characterization of PAoK, showing that such arguments can be made extremely laconic, with the prover sending a single bit, and assumed to have only one round (i.e., two messages) of communication without loss of generality.
We additionally explore PAoK satisfying additional properties (including zero-knowledge and the possibility of re-using the same challenge across multiple executions with the prover), present several constructions of PAoK relying on different cryptographic tools, and discuss applications to cryptography
Path, theme and narrative in open plan exhibition settings
Three arguments are made based on the analysis of science exhibitions. First,sufficiently refined techniques of spatial analysis allow us to model the impact oflayout upon visitors' paths, even in moderately sized open plans which allow almostrandom patterns of movement and relatively unobstructed visibility. Second, newlydeveloped or adapted techniques of analysis allow us to make a transition frommodeling the mechanics of spatial movement (the way in which movement is affectedby the distribution of obstacles and boundaries), to modeling the manner in whichmovement might register additional aspects of visual information. Third, theadvantages of such purely spatial modes of analysis extend into providing us with asharper understanding of some of the pragmatic constrains within which exhibitioncontent is conceived and designed
Path, theme and narrative in open plan exhibition settings
Three arguments are made based on the analysis of science exhibitions. First,sufficiently refined techniques of spatial analysis allow us to model the impact oflayout upon visitors' paths, even in moderately sized open plans which allow almostrandom patterns of movement and relatively unobstructed visibility. Second, newlydeveloped or adapted techniques of analysis allow us to make a transition frommodeling the mechanics of spatial movement (the way in which movement is affectedby the distribution of obstacles and boundaries), to modeling the manner in whichmovement might register additional aspects of visual information. Third, theadvantages of such purely spatial modes of analysis extend into providing us with asharper understanding of some of the pragmatic constrains within which exhibitioncontent is conceived and designed
Polymers and percolation in two dimensions and twisted N=2 supersymmetry
It is shown how twisted N=2 (k=1) provides for the first time a complete
conformal field theory description of the usual geometrical phase transitions
in two dimensions, like polymers, percolation or brownian motion. In
particular, four point functions of operators with half integer Kac labels are
computed, together with geometrical operator products. In addition to Ramond
and Neveu Schwartz, a sector with quarter twists has to be introduced. The role
of fermions and their various sectors is geometrically interpreted, modular
invariant partition functions are built. The presence of twisted N=2 is traced
back to the Parisi Sourlas supersymmetry. It is shown that N=2 leads also to
new non trivial predictions; for instance the fractal dimension of the
percolation backbone in two dimensions is conjectured to be D=25/16, in good
agreement with numerical studies.Comment: 42 pages (without figures
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