scholarly journals An Approach of Statistical Corrections to Interactions in Hadron Resonance Gas

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Mahmoud Hanafy ◽  
Muhammad Maher

We propose a new model for hadrons with quantum mechanical attractive and repulsive interactions sensitive to some spatial correlation length parameter inspired by the Beth-Uhlenbeck quantum mechanical nonideal gas model (Uhlenbeck and Beth, 1937). We confront the thermodynamics calculated using our model with a corresponding recent lattice data at four different values of the baryon chemical potential, μ b = 0 , 170 , 340 , 425   MeV over temperatures ranging from 130   MeV to 200   MeV and for five values for the correlation length ranging from 0 to 0.2 fm. For equilibrium temperatures up to the vicinity of the chiral phase transition temperature ≃160 MeV, a decent fitting between the model and the lattice data is observed for different values of r , especially at μ b , r = 170 , 0.05 , 340 , 0.1 , and   340 , 0.15 , where μ b is in MeV and r is in fm. For the vanishing chemical potential, the uncorrelated model r = 0 , which corresponds to the ideal hadron resonance gas model, seems to offer the best fit. The quantum hadron correlations seem to be more probable at nonvanishing chemical potentials, especially within the range μ b ∈ 170 , 340   MeV .

2016 ◽  
Vol 230 (10) ◽  
Author(s):  
Elisabetta Arato ◽  
Angelo Morro

AbstractThe paper applies the theory of mixtures to the chemical reaction rate. Concerning the time dependence of pressure, it is shown that pressure increases, is constant or decreases depending on the analogous behaviour of mole numbers. The results are established analytically and then numerically for the ideal gas, the van der Waals and the truncated virial equations. Next, in connection with the ideal gas model, Denbigh assumption is established by starting from the thermodynamic relation between (partial) pressure and Helmholtz free energy. Moreover, it is pointed out that the chemical potential does not exactly equal the partial derivative of the Gibbs free energy with respect to the corresponding mole number. This in turn is shown to imply that the evolution of a reaction is provided by the chemical potentials rather than by the derivative of the Gibbs free energy. Subject to the assumption of ideal gas for the constituents, as a thermodynamic requirement it is shown that if the number of moles increases the reaction is favoured by low pressures, and viceversa, and explicit estimates are established.


2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Pengfei Zhang

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.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seyyed Mohammad Mehdi Moshiri ◽  
Najmeh Nozhat

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.


Cerâmica ◽  
2008 ◽  
Vol 54 (331) ◽  
pp. 356-360 ◽  
Author(s):  
A. Blandine ◽  
G. Bernard ◽  
B. Essaïd

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.


2010 ◽  
Vol 663-665 ◽  
pp. 108-112
Author(s):  
Chao Liang Ding ◽  
Min Teng ◽  
Zhi Guo Zhao ◽  
Liu Zhan Pan

Using the coherence theory of non-stationary fields and the method of Fourier transform, the spectral properties of spatially and spectrally partially coherent Gaussian Schell-model pulsed (GSMP) beams in fused-silica glass medium are studied and analyzed numerically. It is shown that the spectral shift takes place, which depends on the position of the field point, spatial correlation length, temporal coherence length and dispersive property of medium, as GSMP beams propagate in fused-silica glass medium. The on-axis spectrum is blue-shifted, and the relative spectral shift increases with increasing propagation distance, and decreases as the spatial correlation length and temporal coherence length increases, and then approaches an asymptotic value. The dispersive property of medium plays an important role in the spectral properties of spatially and spectrally partially coherent beams.


2019 ◽  
Vol 34 (01) ◽  
pp. 1950003
Author(s):  
Yu-Qiang Cui ◽  
Zhong-Liang Pan

We investigate the finite-temperature and zero quark chemical potential QCD chiral phase transition of strongly interacting matter within the two-flavor Nambu–Jona-Lasinio (NJL) model as well as the proper time regularization. We use two different regularization processes, as discussed in Refs. 36 and 37, separately, to discuss how the effective mass M varies with the temperature T. Based on the calculation, we find that the M of both regularization schemes decreases when T increases. However, for three different parameter sets, quite different behaviors will show up. The results obtained by the method in Ref. 36 are very close to each other, but those in Ref. 37 are getting farther and farther from each other. This means that although the method in Ref. 37 seems physically more reasonable, it loses the advantage in Ref. 36 of a small parameter dependence. In addition, we also, find that two regularization schemes provide similar results when T [Formula: see text] 100 MeV, while when T is larger than 100 MeV, the difference becomes obvious: the M calculated by the method in Ref. 36 decreases more rapidly than that in Ref. 37.


Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2042 ◽  
Author(s):  
Hanqing Liu ◽  
Jianfeng Tan ◽  
Peiguo Liu ◽  
Li-an Bian ◽  
Song Zha

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.


2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Guruprasad Kadam ◽  
Swapnali Pawar

We study the equation of state (EoS) of hot and dense hadron gas by incorporating the excluded volume corrections into the ideal hadron resonance gas (HRG) model. The total hadron mass spectrum of the model is the sum of the discrete mass spectrum consisting of all the experimentally known hadrons and the exponentially rising continuous Hagedorn states. We confront the EoS of the model with lattice quantum chromodynamics (LQCD) results at finite baryon chemical potential. We find that this modified HRG model reproduces the LQCD results up to T=160 MeV at zero as well as finite baryon chemical potential. We further estimate the shear viscosity within the ambit of this model in the context of heavy-ion collision experiments.


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