Generation of low tehmperature series for Ising models with nearest and next nearest neighbor interactions

1976 ◽  
Vol 54 (16) ◽  
pp. 1646-1650 ◽  
Author(s):  
M. Plischke ◽  
C. F. S. Chan
Keyword(s):  
Low Temperature ◽  
Nearest Neighbor ◽  
Tricritical Point ◽  
Ising Models ◽  
Temperature Data ◽  
Temperature Series ◽  
Bcc Lattice ◽  
Special Cases ◽  
Ising Antiferromagnet ◽  
Ferromagnetic Interactions

We have generalized the code method of Sykes et al. and applied it to the Ising model with nearest and next nearest neighbor interactions. On the bcc lattice, we have obtained the first seven low temperature polynomials for arbitrary sign of the interactions. Special cases of this model are the Ising ferromagnet and the Ising antiferromagnet with next nearest neighbor ferromagnetic interactions. The latter system exhibits a tricritical point which we plan to study using our low temperature data and high temperature series to be obtained in the future.

Tricritical phenomena in an Ising model with nearest- and next-nearest-neighbor interactions

1977 ◽  
Vol 55 (13) ◽  
pp. 1125-1133 ◽  
Author(s):  
M. Plischke ◽  
D. Zobin
Keyword(s):  
Field Theory ◽  
High Temperature ◽  
Ising Model ◽  
Nearest Neighbor ◽  
Tricritical Point ◽  
Mean Field Theory ◽  
Mean Field ◽  
Temperature Series ◽  
Bcc Lattice ◽  
Ferromagnetic Interactions

We report on the analysis of low and high temperature series for the Ising model with nearest-neighbor antiferromagnetic and next-nearest-neighbor ferromagnetic interactions on the bcc lattice. The high temperature series are complete to β7, the low temperature series to u37. We determine the phase diagram, locate the tricritical point, and estimate the tricritical exponents. The tricritical exponents are only in fair agreement with the predictions of tricritical mean field theory.

HOLE–SPIN COUPLING AND SPIN DISTORTION IN HIGH Tc SUPERCONDUCTORS

1995 ◽  
Vol 09 (24) ◽  
pp. 1589-1594
Author(s):  
M. TIWARI ◽  
R. A. SINGH
Keyword(s):  
Correlation Function ◽  
Green Function ◽  
Low Temperature ◽  
Function Theory ◽  
Expansion Method ◽  
Temperature Series ◽  
Spin Coupling ◽  
High Tc Superconductors ◽  
High Tc ◽  
Series Expansion Method

The effect of hole–spin coupling together with spin distortion on the energy and hole correlation function have been studied in detail. Standard Green function theory and Low Temperature Series Expansion method have been utilised to get analytical results.

Depth and seasonal biases in organic temperature proxies: a modelling study

2021 ◽  
Author(s):  
Devika Varma ◽  
Gert-Jan Reichart ◽  
Stefan Schouten
Keyword(s):  
Low Temperature ◽  
Probability Density Functions ◽  
Temperature Data ◽  
Sea Surface ◽  
Density Functions ◽  
High Latitudes ◽  
Mean Sea Surface ◽  
Temperature Signal ◽  
Instrumental Temperature ◽  
Nutrient Data

<p>For more than a decade TEX<sub>86</sub> and U<sup>K’</sup><sub>37</sub>, derived from ratios of biomarker lipids have widely been used as organic paleotemperature proxies. Yet, these proxies, especially TEX<sub>86</sub>, have several uncertainties associated with factors such as depth and seasonal biases which are complicating its application as an annual mean sea-surface temperature (SST) proxy. To constrain this impact, we performed a relatively simple modelling exercise where we use instrumental temperature and nutrient data from 40 locations across the globe to predict theoretical proxy values and compare them with measured core-top proxy values.</p><p>The model first uses instrumental nutrient and temperature data, and probability density functions to predict the theoretical depth occurrence of the source organisms of the two proxies. Additionally, seasonal bias was introduced by predicting seasonal occurrences using instrumental nutrient and chlorophyll data. This was used to calculate the depth- and season weighed temperature signal annually deposited in the sediment, which in turn was converted to theoretical proxy values using culture or mesocosm calibrations. This showed, as expected, that depth and seasonal biases introduced scatter in the correlation between theoretical proxy values and annual mean SST but still highly significant for both U<sup>K’</sup><sub>37</sub> (r<sup>2</sup>= 0.96), and TEX<sub>86</sub> (r<sup>2</sup>= 0.77). We find that the theoretical proxy values are much lower than measured proxy value for TEX<sub>86</sub>, which tentatively suggests that TEX<sub>86 </sub>might in fact be coming from shallower depths or that the mesocosm calibration is incorrect. Our model for U<sup>K’</sup><sub>37</sub> results in theoretical values similar to measured values except for low temperature locations. This might suggest an influence of seasonal bias towards more warmer summer seasons which is more pronounced in high latitudes than in tropics.</p>

scholarly journals Thermodynamic and Elastic Properties of Interstitial Alloy FeC with BCC Structure at Zero Pressure

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Bui Duc Tinh ◽  
Nguyen Quang Hoc ◽  
Dinh Quang Vinh ◽  
Tran Dinh Cuong ◽  
Nguyen Duc Hien
Keyword(s):  
Nearest Neighbor ◽  
Young Modulus ◽  
Thermodynamic Quantities ◽  
Atom Concentration ◽  
Main Metal ◽  
Special Cases ◽  
Analytic Expressions ◽  
Rigidity Modulus ◽  
Bcc Structure ◽  
The Mean

The analytic expressions for the thermodynamic and elastic quantities such as the mean nearest neighbor distance, the free energy, the isothermal compressibility, the thermal expansion coefficient, the heat capacities at constant volume and at constant pressure, the Young modulus, the bulk modulus, the rigidity modulus, and the elastic constants of binary interstitial alloy with body-centered cubic (BCC) structure, and the small concentration of interstitial atoms (below 5%) are derived by the statistical moment method. The theoretical results are applied to interstitial alloy FeC in the interval of temperature from 100 to 1000 K and in the interval of interstitial atom concentration from 0 to 5%. In special cases, we obtain the thermodynamic quantities of main metal Fe with BCC structure. Our calculated results for some thermodynamic and elastic quantities of main metal Fe and alloy FeC are compared with experiments.

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