Thermodynamic analysis of an antiferromagnet Ising system

2020 ◽  
pp. 2150095
Author(s):  
Shi-Yu Jiao ◽  
Ji-Xuan Hou
Keyword(s):  
Heat Capacity ◽  
Thermodynamic Analysis ◽  
Mean Field ◽  
Thermodynamic Quantities ◽  
Ising System ◽  
Ergodicity Breaking ◽  
Antiferromagnetic Model

A mean field antiferromagnetic model with both short and long interaction was studied via the microcanonical approach. The thermodynamic quantities such as temperature and entropy were calculated theoretically. The ergodicity breaking and negative heat capacity could be encountered in this system.

HEAT CAPACITY MEASUREMENTS ON THE DILUTED ISING SYSTEM Cs3CopZn1-pCl5

1971 ◽  
Vol 32 (C1) ◽  
pp. C1-1008-C1-1009 ◽  
Author(s):  
E. LAGENDIJK ◽  
W. J. HUISKAMP ◽  
P. F. BONGERS
Keyword(s):  
Heat Capacity ◽  
Ising System ◽  
Heat Capacity Measurements

scholarly journals Phase diagram of the selfinteracting particle­-antiparticle boson system

2021 ◽  
Vol 29 (1) ◽  
pp. 5-14
Author(s):  
D. Anchishkin ◽  
V. Gnatovskyy ◽  
D. Zhuravel ◽  
V. Karpenko
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Phase Diagrams ◽  
Canonical Ensemble ◽  
Bose Condensate ◽  
Mean Field ◽  
Thermodynamic Quantities ◽  
Boson System ◽  
The Mean

A system of interacting relativistic bosons at finite temperatures and isospin densities is studied within the framework of the Skyrme­like mean­field model. The mean field contains both attractive and repulsive terms. The consideration is taken within the framework of the Canonical Ensemble and the isospin­density dependencies of thermodynamic quantities is obtained, in particular as the phase diagrams. It is shown that in such a system, in addition to the formation of a Bose­Einstein condensate, a liquid­gas phase transition is possible. We prove that the multi­boson system develops the Bose condensate for particles of high­density component only.

Entropy bound of horizons of some regular black holes

2020 ◽  
Vol 35 (10) ◽  
pp. 2050070
Author(s):  
Ujjal Debnath
Keyword(s):  
Black Holes ◽  
Heat Capacity ◽  
Black Hole ◽  
Specific Heat ◽  
Surface Area ◽  
Event Horizon ◽  
Specific Heat Capacity ◽  
Thermodynamic Quantities ◽  
Event Horizons ◽  
Regular Black Hole

We study the four-dimensional (i) modified Bardeen black hole, (ii) modified Hayward black hole, (iii) charged regular black hole and (iv) magnetically charged regular black hole. For modified Bardeen black hole and modified Hayward black hole, we found only one horizon (event horizon) and then we found some thermodynamic quantities like the entropy, surface area, irreducible mass, temperature, Komar energy and specific heat capacity on the event horizon. We here study the bounds of the above thermodynamic quantities for these black holes on the event horizon. Then, we examine the thermodynamics stability of the black holes with some conditions. Next, we studied the charged regular black hole and magnetically charged regular black hole and found two horizons (Cauchy and event horizons) of these black holes. Then, we found the entropy, surface area, irreducible mass, temperature, Komar energy and specific heat capacity on the Cauchy and event horizons. Then, we get some conditions for thermodynamic stability/instability of the black holes. We found the radius of the extremal horizon and Christodoulou–Ruffiini mass and then analyze the above thermodynamic quantities on the extremal horizon. We calculate the sum/subtraction, product, division and sum/subtraction of inverse of surface areas, entropies, irreducible masses, temperatures, Komar energies and specific heat capacities on both the horizons. From these, we found the bounds of the above quantities on the horizons.

scholarly journals Rigorous solution of a mean field spin glass model

2000 ◽  
Vol 13 (2) ◽  
pp. 147-160
Author(s):  
T. C. Dorlas ◽  
J. R. Wedagedera
Keyword(s):  
Spin Glass ◽  
Large Deviation ◽  
Mean Field ◽  
Almost Sure Convergence ◽  
Thermodynamic Quantities ◽  
Convergence Criteria ◽  
Spin Glass Model ◽  
Rigorous Solution ◽  
Glass Model ◽  
Null Set

A separable spin glass model whose exchange integral takes the form Jij=J(ξi1ξj2+ξi2ξj1) which was solved by van Hemmen et al. [12] using large deviation theory [14] is rigorously treated. The almost sure convergence criteria associated with the cumulant generating function C(t) with respect to the quenched random variables ξ is carefully investigated, and it is proved that the related excluded null set 𝒩 is independent of t. The free energy and hence the other thermodynamic quantities are rederived using Varadhan's Large Deviation Theorem. A simulation is also presented for the entropy when ξ assumes a Gaussian distribution.

scholarly journals Thermodynamics of black holes in Rastall gravity

2018 ◽  
Vol 27 (07) ◽  
pp. 1850069 ◽  
Author(s):  
Iarley P. Lobo ◽  
H. Moradpour ◽  
J. P. Morais Graça ◽  
I. G. Salako
Keyword(s):  
Black Holes ◽  
Heat Capacity ◽  
General Relativity ◽  
Black Hole ◽  
Momentum Conservation ◽  
Thermodynamic Quantities ◽  
Horizon Radius ◽  
Thermodynamics Of Black Holes ◽  
Matter Fields ◽  
Energy Momentum Conservation

A promising theory in modifying general relativity (GR) by violating the ordinary energy–momentum conservation law in curved spacetime is the Rastall theory of gravity. In this theory, geometry and matter fields are coupled to each other in a nonminimal way. Here, we study thermodynamic properties of some black hole (BH) solutions in this framework, and compare our results with those of GR. We demonstrate how the presence of these matter sources amplifies the effects caused by the Rastall parameter in thermodynamic quantities. Our investigation also shows that BHs with radius smaller than a certain amount ([Formula: see text]) have negative heat capacity in the Rastall framework. In fact, it is a lower bound for the possible values of horizon radius satisfied by the stable BHs.

Bose Liquid Mean-Field Theory with Application to HeI

2019 ◽  
Vol 26 (02) ◽  
pp. 1950005
Author(s):  
Jan Maćkowiak
Keyword(s):  
Field Theory ◽  
Heat Capacity ◽  
Temperature Dependence ◽  
Mean Field Theory ◽  
Mean Field ◽  
Liquid Structure ◽  
Experimental Plot ◽  
Bose Liquid ◽  
Ordered Motion ◽  
Good Agreement

A mean-field theory is developed for a Bose liquid enclosed in a large vessel 𝒱. In accord with liquid structure concepts of Mitus et al., the liquid in 𝒱 is assumed to consist of adjacent macroscopic subregions Λk. In each subregion the bosons perform a locally ordered motion with prevailing orientation k + x, which varies randomly when passing from one subregion to another. |k| is constant, whereas temperature dependence of |x| is governed by a mean-field theory (MFT). The theory is applied to simulate HeI heat capacity CV (T) at T > Tλ = 2.17 K and CV (T) singularity at [Formula: see text]. The MFT numerical heat capacity Cn(T) = ΔE/ΔT exhibits behaviour characteristic of a singularity at [Formula: see text]: rapid increase with decreasing ΔT. Apart from [Formula: see text], good agreement of Cn(T) with CV(T) experimental plot is also found above Tλ, at T ∊ (Tλ, 3K].

HYSTERESIS IN A MEAN-FIELD SPIN MODEL: OSCILLATION BEHAVIOR AND NEGATIVE ENERGY DISSIPATION

2005 ◽  
Vol 19 (23) ◽  
pp. 1131-1140 ◽  
Author(s):  
HUAI-YU WANG
Keyword(s):  
Energy Dissipation ◽  
Field Strength ◽  
Mean Field ◽  
Equation Of Motion ◽  
Negative Energy ◽  
Spin Model ◽  
Oscillation Regime ◽  
Ising System ◽  
Loop Area ◽  
Hysteresis Loop Area

For a mean-field ferromagnetic Ising system subject to a rotating transverse external field and a bath, the hysteresis loop area is studied by a complete analytical solution of the equation of motion of magnetization. In any cycle, the loop area is proportional to the field when the field strength is small and oscillates when the field strength is strong. The oscillation comes from the modulation of the behavior of magnetization with a frequency related to the field strength, which is caused by interaction between the Ising system and the bath. In the oscillation regime, the loop area can be negative except in the first cycle.

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