NOTE ON ANALYTICAL STUDIES OF ONE-DIMENSIONAL HOLOGRAPHIC SUPERCONDUCTORS

2012 ◽  
Vol 27 (02) ◽  
pp. 1250001 ◽  
Author(s):  
RAN LI

We employ the variational method for the Sturm–Liouville eigenvalue problem to analytically study phase transition of one-dimensional holographic superconductors. It is shown that this method is not a very powerful method to analytically calculate the properties of holographic superconductors. From the analytical treatment of scalar operator condensate at critical temperature, we also show that the mean-field critical exponent 1/2 results from the coupling term between scalar field and vector field, which may be an universal property of holographic superconductors with a similar coupling term in their equations of motion.

2016 ◽  
Vol 26 (06) ◽  
pp. 1750050 ◽  
Author(s):  
A. Sheykhi ◽  
F. Shaker

We analytically study the properties of a [Formula: see text]-dimensional [Formula: see text]-wave holographic superconductor in the presence of exponential nonlinear (EN) electrodynamics. We consider the case in which the scalar and gauge fields back react on the background metric. Employing the analytical Sturm–Liouville method, we find that in the black hole background, the nonlinear electrodynamics correction will affect the properties of the holographic superconductors. We find that with increasing both backreaction and nonlinear parameters, the scalar hair condensation on the boundary will develop more difficult. We obtain the relation connecting the critical temperature with the charge density. Our analytical results support that, even in the presence of the nonlinear electrodynamics and backreaction, the phase transition for the holographic superconductor still belongs to the second-order and the critical exponent of the system always takes the mean-field value [Formula: see text].


Author(s):  
Guangze Gu ◽  
Changfeng Gui ◽  
Yeyao Hu ◽  
Qinfeng Li

Abstract We study the following mean field equation on a flat torus $T:=\mathbb{C}/(\mathbb{Z}+\mathbb{Z}\tau )$: $$\begin{equation*} \varDelta u + \rho \left(\frac{e^{u}}{\int_{T}e^u}-\frac{1}{|T|}\right)=0, \end{equation*}$$where $ \tau \in \mathbb{C}, \mbox{Im}\ \tau>0$, and $|T|$ denotes the total area of the torus. We first prove that the solutions are evenly symmetric about any critical point of $u$ provided that $\rho \leq 8\pi $. Based on this crucial symmetry result, we are able to establish further the uniqueness of the solution if $\rho \leq \min{\{8\pi ,\lambda _1(T)|T|\}}$. Furthermore, we also classify all one-dimensional solutions by showing that the level sets must be closed geodesics.


1992 ◽  
Vol 07 (28) ◽  
pp. 2627-2636
Author(s):  
NATHAN WEISS

We study the quantum field theory of non-relativistic bosons coupled to a Chern-Simons gauge field at nonzero particle density. This field theory is relevant to the study of anyon superconductors in which the anyons are described as bosons with a statistical interaction. We show that it is possible to find a mean field solution to the equations of motion for this system which has some of the features of Bose condensation. The mean field solution consists of a lattice of vortices each carrying a single quantum of statistical magnetic flux. We speculate on the effects of the quantum corrections to this mean field solution. We argue that the mean field solution is only stable under quantum corrections if the Chern-Simons coefficient N=2πθ/g2 is an integer. Consequences for anyon superconductivity are presented. A simple explanation for the Meissner effect in this system is discussed.


1996 ◽  
Vol 179 (3) ◽  
pp. 623-646 ◽  
Author(s):  
D. H. U. Marchetti ◽  
P. A. Faria da Veiga ◽  
T. R. Hurd

2007 ◽  
Vol 18 (09) ◽  
pp. 1459-1473 ◽  
Author(s):  
MALIACKAL POULO JOY ◽  
DONALD E. INGBER ◽  
SUI HUANG

Random Boolean networks have been used as simple models of gene regulatory networks, enabling the study of the dynamic behavior of complex biological systems. However, analytical treatment has been difficult because of the structural heterogeneity and the vast state space of these networks. Here we used mean field approximations to analyze the dynamics of a class of Boolean networks in which nodes have random degree (connectivity) distributions, characterized by the mean degree k and variance D. To achieve this we generalized the simple cellular automata rule 126 and used it as the Boolean function for all nodes. The equation for the evolution of the density of the network state is presented as a one-dimensional map for various input degree distributions, with k and D as the control parameters. The mean field dynamics is compared with the data obtained from the simulations of the Boolean network. Bifurcation diagrams and Lyapunov exponents for different parameter values were computed for the map, showing period doubling route to chaos with increasing k. Onset of chaos was delayed (occurred at higher k) with the increase in variance D of the connectivity. Thus, the network tends to be less chaotic when the heterogeneity, as measured by the variance of connectivity, was higher.


2006 ◽  
Vol 20 (30n31) ◽  
pp. 5199-5203
Author(s):  
D. M. JEZEK ◽  
H. M. CATALDO

We study a confined mixture of Rb and K atoms in a one dimensional optical lattice, at low temperature, in the quanta1 degeneracy regime. This mixture exhibits an attractive boson-fermion interaction, and thus above certain values of the number of particles the mixture collapses. We investigate, in the mean-field approximation, the curve for which this phenomenon occurs, in the space of number of particles of both species. This is done for different types of optical lattices.


2005 ◽  
Vol 16 (11) ◽  
pp. 1771-1783 ◽  
Author(s):  
SYLWIA KRUPA ◽  
KATARZYNA SZNAJD-WERON

In this paper we compare the relaxation in several versions of the Sznajd model (SM) with random sequential updating on the chain and square lattice. We start by reviewing briefly all proposed one-dimensional versions of SM. Next, we compare the results obtained from Monte Carlo simulations with the mean field results obtained by Slanina and Lavicka. Finally, we investigate the relaxation on the square lattice and compare two generalizations of SM, one suggested by Stauffer et al. and another by Galam. We show that there are no qualitative differences between these two approaches, although the relaxation within the Galam rule is faster than within the well known Stauffer et al. rule.


1994 ◽  
Vol 08 (19) ◽  
pp. 1195-1200 ◽  
Author(s):  
V. L. SAFONOV ◽  
A. V. ROZHKOV

The hypothesis that conduction electrons in a one-dimensional crystal obey para-Fermi statistics is discussed. Thermal properties of Fröhlich's model in the mean-field approximation are calculated within the framework of this hypothesis. It is shown that the temperature of the phase transition to a charge density wave state is greater in a system with parastatistics.


2017 ◽  
Vol 19 (28) ◽  
pp. 18514-18518 ◽  
Author(s):  
Shasha Yi ◽  
Cong Pan ◽  
Liming Hu ◽  
Zhonghan Hu

Using the left–right symmetry in one-dimensional systems, the mean field idea can be implemented to yield accurate structure corrections.


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