MONTE-CARLO ANALYSIS OF THE ABELIAN SURFACE GAUGE MODEL

1992 ◽  
Vol 07 (18) ◽  
pp. 1601-1607 ◽  
Author(s):  
M. BAIG ◽  
A. TRIAS
Keyword(s):  
Monte Carlo ◽  
Phase Structure ◽  
Three Dimensional ◽  
Monte Carlo Analysis ◽  
Abelian Surface ◽  
Gauge Model ◽  
Monte Carlo Techniques ◽  
Gauge Models ◽  
Lattice Gauge ◽  
Duality Relations

We present the first numerical results from a lattice formulation of the Abelian surface gauge model which accounts for three-index fields required in theories based on an antisymmetrical potential. For this purpose we have defined a lattice gauge model in such a way that field variables are assigned to the plaquettes and the interaction is defined through elementary three-dimensional cubes. The phase structure of the Abelian Z(2) case has been determined using Monte-Carlo techniques. Duality relations to spin and gauge models are also studied.

scholarly journals U(1) LATTICE GAUGE MODEL FOR UNCONVENTIONAL SUPERCONDUCTORS: LINK COOPER PAIR AS DUAL GAUGE FIELD

2008 ◽  
Vol 23 (33) ◽  
pp. 2821-2833 ◽  
Author(s):  
KENJI SAWAMURA ◽  
IKUO ICHINOSE ◽  
YUKI MORIBE
Keyword(s):  
Phase Transition ◽  
Electromagnetic Field ◽  
Gauge Field ◽  
Phase Structure ◽  
Cooper Pair ◽  
Three Dimensional ◽  
Gauge Model ◽  
Coulomb Interactions ◽  
Lattice Gauge ◽  
New Type

In this paper we study a new type of lattice gauge model that was proposed in the previous papers for describing unconventional superconductivity (SC). In this model, the Cooper-pair (CP) field is defined on lattice links in order to describe d-wave SC. The CP field can be regarded as a U(1) lattice gauge field dual to the electromagnetic field, and the SC (Higgs) phase transition takes place as a result of the phase coherence of the CP field. Effects of the long-range Coulomb interactions between the CPs and fluctuations of the electromagnetic field are taken into account. We investigate the phase structure of the model and the critical behavior by means of the Monte Carlo simulations. We find that the parameter, which controls the fluxes (vortices) of the CP, strongly influences the phase structure. In three-dimensional case, the model has rich phase structure. In particular, there is a "monopole proliferation" phase transition besides the SC phase transition. Depending on the parameters, this transition exists within the SC phase or takes place simultaneously with the SC transition. This new type of transition is relevant for unconventional SCs with strong spatial three-dimensionality and to be observed by experiments.

scholarly journals Srna - Monte Carlo codes for proton transport simulation in combined and voxelized geometries

2002 ◽  
Vol 17 (1-2) ◽  
pp. 27-36 ◽  
Author(s):  
Radovan Ilic ◽  
Darko Lalic ◽  
Srboljub Stankovic
Keyword(s):  
Monte Carlo ◽  
Proton Transport ◽  
Transition Probabilities ◽  
Three Dimensional ◽  
Monte Carlo Techniques ◽  
Transport Simulation ◽  
Distribution Calculation ◽  
Beam Characterization ◽  
Positron Emitters ◽  
Tomography Data

This paper describes new Monte Carlo codes for proton transport simulations in complex geometrical forms and in materials of different composition. The SRNA codes were developed for three dimensional (3D) dose distribution calculation in proton therapy and dosimetry. The model of these codes is based on the theory of proton multiple scattering and a simple model of compound nucleus decay. The developed package consists of two codes: SRNA-2KG and SRNA-VOX. The first code simulates proton transport in combined geometry that can be described by planes and second order surfaces. The second one uses the voxelized geometry of material zones and is specifically adopted for the application of patient computer tomography data. Transition probabilities for both codes are given by the SRNADAT program. In this paper, we will present the models and algorithms of our programs, as well as the results of the numerical experiments we have carried out applying them, along with the results of proton transport simulation obtained through the PETRA and GEANT programs. The simulation of the proton beam characterization by means of the Multi-Layer Faraday Cup and spatial distribution of positron emitters obtained by our program indicate the imminent application of Monte Carlo techniques in clinical practice.

scholarly journals Monte Carlo Analysis of Optical Interactions in Reflectance and Transmittance Finger Photoplethysmography

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 789 ◽  
Author(s):  
Subhasri Chatterjee ◽  
Panayiotis Kyriacou
Keyword(s):  
Monte Carlo ◽  
Penetration Depth ◽  
Three Dimensional ◽  
Region Of Interest ◽  
Monte Carlo Analysis ◽  
Optical Parameters ◽  
Arterial Blood ◽  
Fundamental Information ◽  
The Individual ◽  
Human Finger

Photoplethysmography (PPG) is a non-invasive photometric technique that measures the volume changes in arterial blood. Recent studies have reported limitations in developing and optimising PPG-based sensing technologies due to unavailability of the fundamental information such as PPG-pathlength and penetration depth in a certain region of interest (ROI) in the human body. In this paper, a robust computational model of a dual wavelength PPG system was developed using Monte Carlo technique. A three-dimensional heterogeneous volume of a specific ROI (i.e., human finger) was exposed at the red (660 nm) and infrared (940 nm) wavelengths in the reflectance and transmittance modalities of PPG. The optical interactions with the individual pulsatile and non-pulsatile tissue-components were demonstrated and the optical parameters (e.g., pathlength, penetration depth, absorbance, reflectance and transmittance) were investigated. Results optimised the source-detector separation for a reflectance finger-PPG sensor. The analysis with the recorded absorbance, reflectance and transmittance confirmed the maximum and minimum impact of the dermis and bone tissue-layers, respectively, in the formation of a PPG signal. The results presented in the paper provide the necessary information to develop PPG-based transcutaneous sensors and to understand the origin of the ac and dc components of the PPG signal.

scholarly journals THE EFFECTIVE STRING OF 3D Z2 GAUGE THEORY AS A c = 1 COMPACTIFIED CFT

1993 ◽  
Vol 08 (16) ◽  
pp. 2839-2858 ◽  
Author(s):  
M. CASELLE ◽  
F. GLIOZZI ◽  
S. VINTI ◽  
R. FIORE
Keyword(s):  
Field Theory ◽  
Monte Carlo ◽  
Conformal Field Theory ◽  
Central Charge ◽  
Three Dimensional ◽  
String Tension ◽  
Gauge Model ◽  
Expectation Values ◽  
Monte Carlo Test ◽  
Conformal Field

We report on a high precision Monte Carlo test of the three-dimensional Ising gauge model at finite temperature. The string tension σ is extracted from the expectation values of correlations of Polyakov lines. Agreement with the string tension extracted from Wilson loops is found only if the quantum fluctuations of the flux tube are properly taken into account. The central charge of the underlying conformal field theory is c = 1.

EVIDENCE FOR PHASE TRANSITIONS CAUSED BY RADIAL FLUCTUATIONS IN AN SU(2)×U(1) LATTICE GAUGE-HIGGS THEORY

1988 ◽  
Vol 03 (01) ◽  
pp. 23-31 ◽  
Author(s):  
Yasuko Munehisa
Keyword(s):  
Monte Carlo ◽  
Phase Transitions ◽  
Degrees Of Freedom ◽  
Gauge Coupling ◽  
Higgs Field ◽  
Critical Surface ◽  
Monte Carlo Techniques ◽  
Full Theory ◽  
Lattice Gauge ◽  
Symmetric Region

Using Monte Carlo techniques, we study the phase structure of a radially active SU(2)×U(1) lattice gauge-fundamental Higgs theory in its strong U(1) gauge-coupling limit. Our results give first evidence for a critical surface induced by radial fluctuations of the Higgs field, which would extend inside the symmetric region of the full SU(2)×U(1) gauge-Higgs theory. The weak SU (2) gauge-coupling limit of the full theory, the radially active version of the SU(2)global×U(1)local gauge-Higgs theory, is also studied numerically. In this limit, we found no essential effect due to the radial degrees of freedom of the Higgs field.

QCD GLUEBALLS WITHIN A COUPLED CLUSTER APPROACH

2001 ◽  
Vol 15 (10n11) ◽  
pp. 1732-1735 ◽  
Author(s):  
D. SCHÜTTE ◽  
A. WICHMANN ◽  
V. WETHKAMP
Keyword(s):  
Field Theory ◽  
Monte Carlo ◽  
Ground State ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Gauge Field Theory ◽  
Coupled Cluster Method ◽  
Cluster Approach ◽  
Monte Carlo Techniques ◽  
Lattice Gauge

The validity of the coupled cluster method is studied within the lattice gauge field theory given by a SU(2) pure glue theory in 2+1 dimensions. Satisfactory convergence is observed for the ground state, but the method is less successful for the prediction of glueballs. We propose to improve the coupled cluster method for excited state by combining it with standard Monte-Carlo techniques which potentially cure the non-hermiticity problems caused by the truncation.

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