scholarly journals Efficient numerical integration of thermal interaction rates

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
G. Jackson ◽  
M. Laine
Keyword(s):  
Phase Space ◽  
Numerical Integration ◽  
Chemical Potential ◽  
Substantial Contribution ◽  
Thermal Interaction ◽  
The Real ◽  
Chemical Potentials

Abstract In many problems in particle cosmology, interaction rates are dominated by 2 ↔ 2 scatterings, or get a substantial contribution from them, given that 1 ↔ 2 and 1 ↔ 3 reactions are phase-space suppressed. We describe an algorithm to represent, regularize, and evaluate a class of thermal 2 ↔ 2 and 1 ↔ 3 interaction rates for general momenta, masses, chemical potentials, and helicity projections. A key ingredient is an automated inclusion of virtual corrections to 1 ↔ 2 scatterings, which eliminate logarithmic and double-logarithmic IR divergences from the real 2 ↔ 2 and 1 ↔ 3 processes. We also review thermal and chemical potential induced contributions that require resummation if plasma particles are ultrarelativistic.

scholarly journals More on complex Sachdev-Ye-Kitaev eternal wormholes

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Pengfei Zhang
Keyword(s):  
Black Hole ◽  
Ground State ◽  
Effective Action ◽  
Chemical Potential ◽  
Specific Charge ◽  
Zero Temperature ◽  
Small Coupling ◽  
Chemical Potentials ◽  
Quench Dynamics ◽  
Two Sides

Abstract In this work, we study a generalization of the coupled Sachdev-Ye-Kitaev (SYK) model with U(1) charge conservations. The model contains two copies of the complex SYK model at different chemical potentials, coupled by a direct hopping term. In the zero-temperature and small coupling limit with small averaged chemical potential, the ground state is an eternal wormhole connecting two sides, with a specific charge Q = 0, which is equivalent to a thermofield double state. We derive the conformal Green’s functions and determine corresponding IR parameters. At higher chemical potential, the system transit into the black hole phase. We further derive the Schwarzian effective action and study its quench dynamics. Finally, we compare numerical results with the analytical predictions.

scholarly journals Smart optical cross dipole nanoantenna with multibeam pattern

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seyyed Mohammad Mehdi Moshiri ◽  
Najmeh Nozhat
Keyword(s):  
Radiation Pattern ◽  
Chemical Potential ◽  
Monolayer Graphene ◽  
Absorption Characteristic ◽  
Radiation Beam ◽  
Directional Radiation ◽  
Chemical Potentials ◽  
Different Types ◽  
Absorption Power ◽  
Maximum Directivity

AbstractIn this paper, an optical smart multibeam cross dipole nano-antenna has been proposed by combining the absorption characteristic of graphene and applying different arrangements of directors. By introducing a cross dipole nano-antenna with two V-shaped coupled elements, the maximum directivity of 8.79 dBi has been obtained for unidirectional radiation pattern. Also, by applying various arrangements of circular sectors as director, different types of radiation pattern such as bi- and quad-directional have been attained with directivities of 8.63 and 8.42 dBi, respectively, at the wavelength of 1550 nm. The maximum absorption power of graphene can be tuned by choosing an appropriate chemical potential. Therefore, the radiation beam of the proposed multibeam cross dipole nano-antenna has been controlled dynamically by applying a monolayer graphene. By choosing a suitable chemical potential of graphene for each arm of the suggested cross dipole nano-antenna without the director, the unidirectional radiation pattern shifts ± 13° at the wavelength of 1550 nm. Also, for the multibeam nano-antenna with different arrangements of directors, the bi- and quad-directional radiation patterns have been smartly modified to uni- and bi-directional ones with the directivities of 10.1 and 9.54 dBi, respectively. It is because of the graphene performance as an absorptive or transparent element for different chemical potentials. This feature helps us to create a multipath wireless link with the capability to control the accessibility of each receiver.

scholarly journals A structural analytic method on the phase space data of Linac 4 MV photons based on the real world

2021 ◽  
Vol 82 ◽  
pp. 109-113
Author(s):  
Zhenguo Cui ◽  
Songlin Sha ◽  
Yanling Bai
Keyword(s):  
Phase Space ◽  
Real World ◽  
Analytic Method ◽  
The Real ◽  
Space Data

scholarly journals Use of thermodynamic chemical potential diagrams (µCaO, µCO2) to understand the weathering of cement by a slightly carbonated water

Cerâmica ◽  
2008 ◽  
Vol 54 (331) ◽  
pp. 356-360 ◽  
Author(s):  
A. Blandine ◽  
G. Bernard ◽  
B. Essaïd
Keyword(s):  
Chemical Weathering ◽  
Chemical Potential ◽  
Chemical Elements ◽  
Continuous Solid Solution ◽  
The Core ◽  
Chemical Potentials ◽  
Knowing That ◽  
Cement System ◽  
Calcium Silicates ◽  
Hydrated Calcium

Cement is a ubiquitous material that may suffer hazardous weathering. The chemical weathering of cement in natural environment is mostly characterized by the leaching of CaO and the addition of CO2. The different weathering zones that develop at the expense of the cement may be predicted by the help of chemical potential phase diagrams; these diagrams simulate the behaviour of systems open to some chemical elements. Some components have a so-called inert status, that is to say the system is closed for these components, their amount in the system remains constant; some other components have a mobile status, that is to say these components can be exchanged with the outside of the system, their amount can vary from one sample zone to another. The mobile components are represented in the model by their chemical potentials (linked to their concentrations) that are variable in the external environment. The main features of the weathering of a cement system open to CaO and CO2 are predicted in a phase diagram with µCaO et µCO2 as diagram axes. From core to rim, one observes the disappearance of portlandite, ettringite and calcium monosulfoaluminate, the precipitation of calcite and amorphous silica, the modification of the composition of the CSH minerals (hydrated calcium silicates) that see a decrease of their c/s ratio (CaO/SiO2) from the core to the rim of the sample. For the CSH minerals, we have separated their continuous solid solution into three compositions defined by different CaO/SiO2 ratios and called phases 1, 2 and 3: CaO = 0.8, 1.1, 1.8 respectively for one mole of SiO2 knowing that H2O varies in the three compositions.

scholarly journals Tunable Coupled-Resonator-Induced Transparency in a Photonic Crystal System Based on a Multilayer-Insulator Graphene Stack

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2042 ◽  
Author(s):  
Hanqing Liu ◽  
Jianfeng Tan ◽  
Peiguo Liu ◽  
Li-an Bian ◽  
Song Zha
Keyword(s):  
Photonic Crystal ◽  
Optical Sensors ◽  
Chemical Potential ◽  
Structural Parameters ◽  
Multilayer Graphene ◽  
Crystal System ◽  
Chemical Potentials ◽  
Nonlinear Devices ◽  
Induced Transparency ◽  
Coupled Resonator

We achieve the effective modulation of coupled-resonator-induced transparency (CRIT) in a photonic crystal system which consists of photonic crystal waveguide (PCW), defect cavities, and a multilayer graphene-insulator stack (MGIS). Simulation results show that the wavelength of transparency window can be effectively tuned through varying the chemical potential of graphene in MGIS. The peak value of the CRIT effect is closely related to the structural parameters of our proposed system. Tunable Multipeak CRIT is also realized in the four-resonator-coupled photonic crystal system by modulating the chemical potentials of MGISs in different cavity units. This system paves a novel way toward multichannel-selective filters, optical sensors, and nonlinear devices.

Temperature and equilibrium

2021 ◽  
pp. 49-78
Author(s):  
James P. Sethna
Keyword(s):  
Statistical Mechanics ◽  
Chemical Potential ◽  
Density Fluctuations ◽  
High Dimensional ◽  
High Dimensions ◽  
Chemical Potentials ◽  
The World ◽  
Particle Velocities ◽  
The Cost ◽  
Taste And Smell

Statistical mechanics explains the comprehensible behavior of microscopically complex systems by using the weird geometry of high-dimensional spaces, and by relying only on the known conserved quantity: the energy. Particle velocities and density fluctuations are determined by the geometry of spheres and cubes in dimensions with twenty three digits. Temperature, pressure, and chemical potential are defined and derived in terms of the volume of the high-dimensional energy shell, as quantified by the entropy. In particular, temperature is the inverse of the cost of buying energy from the rest of the world, and entropy is the currency being paid. Exercises discuss the weird geometry of high dimensions, how taste and smell measure chemical potentials, equilibrium fluctuations, and classic thermodynamic relations.

scholarly journals Very-High-Eccentricity Librations at Some Higher Order Resonances

1992 ◽  
Vol 152 ◽  
pp. 153-158 ◽  
Author(s):  
J.C. Klafke ◽  
S. Ferraz-Mello ◽  
T. Michtchenko
Keyword(s):  
Phase Space ◽  
Numerical Integration ◽  
Higher Order ◽  
Planar Problem ◽  
High Eccentricity ◽  
Disturbing Potential ◽  
Numerical Exploration ◽  
Numerical Integrations ◽  
Short Period ◽  
Very High

Motions near the 3:1, 4:1 and 5:2 resonances with Jupiter are studied by means of numerical integrations of a semi-analytically averaged Sun-Jupiter-asteroid planar problem. In order to have a model including the very-high-eccentricity regions of the phase space, we adopted a set of local expansions of the disturbing potential, adequate to perform the numerical exploration of regions in the phase space with eccentricities higher than 0.9 (Ferraz-Mello and Klafke, 1991). Individual solutions and qualitative results thus obtained are completely reproduced by numerical integration of the complete equations by filtering off the short-period components of these solutions.

scholarly journals CP VIOLATING ASYMMETRIES OF b QUARKS AND LEPTONS IN $e^+ e^-\to t\bar t$ AND SUPERSYMMETRY

1999 ◽  
Vol 14 (01) ◽  
pp. 1-23 ◽  
Author(s):  
EKATERINA CHRISTOVA
Keyword(s):  
Phase Space ◽  
Cp Violation ◽  
Numerical Results ◽  
The Real ◽  
B Quarks ◽  
Analytic Expressions

The distributions of the single decay b-quarks and leptons from [Formula: see text] assuming CP violation are reviewed. Different asymmetries, sensitive independently to CP violation in the production and in the decay, and sensitive to the real and imaginary parts of dγ and dZ are defined. The analytic expressions are general and independent on the model of CP violation. In most of them all phase space integrations are fulfilled analytically. Numerical results in the MSSM with complex couplings are presented.

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