CRITICAL BEHAVIOR OF A TWO-DIMENSIONAL DILUTE BOSE GAS

2001 ◽  
Vol 15 (20) ◽  
pp. 837-846 ◽  
Author(s):  
M. CRISAN ◽  
I. TIFREA ◽  
D. BODEA ◽  
I. GROSU
Keyword(s):  
Critical Temperature ◽  
Specific Heat ◽  
Coherence Length ◽  
Bose Gas ◽  
Group Method ◽  
Two Dimensional ◽  
Flow Equations ◽  
General Flow ◽  
Dilute Bose Gas ◽  
Arbitrary Dimensions

We applied the Renormalization Group method at finite temperature to reconsider the two-dimensional dilute Bose gas. The general flow equations are obtained for the case of arbitrary dimensions, and by considering the two-dimensional limit, we estimate the value of the critical temperature, coherence length and specific heat. The value of the critical temperature is in agreement with previous calculations performed using the t-matrix method. The coherence length and the specific heat present a non-universal behavior, a logarithmic temperature dependence in the critical region being identified.

The Finite-Size Scaling Study of the Specific Heat and the Binder Parameter of the Two-Dimensional Ising Model for the Fractals Obtained by Using the Model of Diffusion-Limited Aggregation

2009 ◽  
Vol 64 (12) ◽  
pp. 849-854 ◽  
Author(s):  
Ziya Merdan ◽  
Mehmet Bayirli ◽  
Mustafa Kemal Ozturk
Keyword(s):  
Critical Temperature ◽  
Ising Model ◽  
Specific Heat ◽  
Finite Size ◽  
Two Dimensional ◽  
Finite Size Scaling ◽  
Size Scaling ◽  
Infinite Lattice ◽  
Straight Line ◽  
Binder Parameter

The two-dimensional Ising model with nearest-neighbour pair interactions is simulated on the Creutz cellular automaton by using the finite-size lattices with the linear dimensions L = 80, 120, 160, and 200. The temperature variations and the finite-size scaling plots of the specific heat and the Binder parameter verify the theoretically predicted expression near the infinite lattice critical temperature. The approximate values for the critical temperature of the infinite lattice Tc = 2.287(6), Tc = 2.269(3), and Tc =2.271(1) are obtained from the intersection points of specific heat curves, Binder parameter curves, and the straight line fit of specific heat maxima, respectively. These results are in agreement with the theoretical value (Tc =2.269) within the error limits. The values obtained for the critical exponent of the specific heat, α = 0.04(25) and α = 0.03(1), are in agreement with α = 0 predicted by the theory. The values for the Binder parameter by using the finite-size lattices with the linear dimension L = 80, 120, 160, and 200 at Tc = 2.269(3) are calculated as gL(Tc) = −1.833(5), gL(Tc) = −1.834(3), gL(Tc) = −1.832(2), and gL(Tc) = −1.833(2), respectively. The value of the infinite lattice for the Binder parameter, gL(Tc) = −1.834(11), is obtained from the straight line fit of gL(Tc) = −1.833(5), gL(Tc) = −1.834(3), gL(Tc) = −1.832(2), and gL(Tc) = −1.833(2) versus L = 80, 120, 160, and 200, respectively

scholarly journals FLUCTUATION CONTRIBUTION TO THE SPECIFIC HEAT IN NON-FERMI MODELS FOR SUPERCONDUCTIVITY

2000 ◽  
Vol 14 (25n27) ◽  
pp. 2988-2993
Author(s):  
I. Tifrea ◽  
I. Grosu ◽  
M. Crisan
Keyword(s):  
Crossover Study ◽  
Specific Heat ◽  
Green’S Function ◽  
Green's Function ◽  
Normal State ◽  
Coherence Length ◽  
Einstein Condensation ◽  
Two Dimensional ◽  
Bose Einstein Condensation ◽  
Bose Einstein

We investigate the fluctuation contribution to the specific heat of a two-dimensional superconductor with a non-Fermi normal state described by a Anderson Green's function [Formula: see text]. The specific heat corrections contain a term proportional to [Formula: see text] and another logarithmic one. We define a coherence length as function of the non-Fermi paramter α, which shows that a crossover study between BCS and Bose-Einstein condensation is possible by varying the non-Fermi parameter α.

scholarly journals The free energy of the two-dimensional dilute Bose gas. II. Upper bound

2020 ◽  
Vol 61 (6) ◽  
pp. 061901
Author(s):  
Simon Mayer ◽  
Robert Seiringer
Keyword(s):  
Free Energy ◽  
Upper Bound ◽  
Bose Gas ◽  
Two Dimensional ◽  
Dilute Bose Gas

scholarly journals THE FREE ENERGY OF THE TWO-DIMENSIONAL DILUTE BOSE GAS. I. LOWER BOUND

2020 ◽  
Vol 8 ◽  
Author(s):  
ANDREAS DEUCHERT ◽  
SIMON MAYER ◽  
ROBERT SEIRINGER
Keyword(s):  
Free Energy ◽  
Lower Bound ◽  
Unit Volume ◽  
Scattering Length ◽  
Correction Term ◽  
Bose Gas ◽  
Two Dimensional ◽  
Dilute Bose Gas ◽  
The One ◽  
Dilute Limit

We prove a lower bound for the free energy (per unit volume) of the two-dimensional Bose gas in the thermodynamic limit. We show that the free energy at density $\unicode[STIX]{x1D70C}$ and inverse temperature $\unicode[STIX]{x1D6FD}$ differs from the one of the noninteracting system by the correction term $4\unicode[STIX]{x1D70B}\unicode[STIX]{x1D70C}^{2}|\ln \,a^{2}\unicode[STIX]{x1D70C}|^{-1}(2-[1-\unicode[STIX]{x1D6FD}_{\text{c}}/\unicode[STIX]{x1D6FD}]_{+}^{2})$ . Here, $a$ is the scattering length of the interaction potential, $[\cdot ]_{+}=\max \{0,\cdot \}$ and $\unicode[STIX]{x1D6FD}_{\text{c}}$ is the inverse Berezinskii–Kosterlitz–Thouless critical temperature for superfluidity. The result is valid in the dilute limit $a^{2}\unicode[STIX]{x1D70C}\ll 1$ and if $\unicode[STIX]{x1D6FD}\unicode[STIX]{x1D70C}\gtrsim 1$ .

Two dimensional CrGa2Se4: A spin-gapless ferromagnetic semiconductor with inclined uniaxial anisotropy

Nanoscale ◽  
2021 ◽  
Author(s):  
Qian Chen ◽  
Ruqian Wang ◽  
Zhaocong Huang ◽  
Shijun Yuan ◽  
Haowei Wang ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Material Science ◽  
2D Materials ◽  
Uniaxial Anisotropy ◽  
Magnetic Semiconductor ◽  
Ferromagnetic Semiconductor ◽  
Two Dimensional ◽  
High Critical Temperature

The magnetic semiconductor with high critical temperature has long been the focus in material science and recently is also known as one of the fundamental questions in two-dimensional (2D) materials....

scholarly journals Crossover in the dynamical critical exponent of a quenched two-dimensional Bose gas

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
A. J. Groszek ◽  
P. Comaron ◽  
N. P. Proukakis ◽  
T. P. Billam
Keyword(s):  
Critical Exponent ◽  
Bose Gas ◽  
Two Dimensional
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