001package models;
002
003/**
004 * The "sinh-Ising model" is an amalgamation of the sinh-Gordon and the Ising models.
005 * 
006 * Its scattering function is <em>minus</em> the sinh-Gordon scattering function:
007 * 
008 * \[ S(\zeta) = - \frac{\sinh \zeta - i \sin B \pi/2 }{\sinh \zeta + i \sin B \pi/2 }. \]
009 * 
010 * 
011 * Correspondingly, the minimal solution is a product of the sinh-Gordon
012 * minimal solution and that of the Ising model, with an additional factor to cancel the double zero at \( \zeta=0 \).
013 * Explicitly,
014 * 
015 * \[ F_\text{min}(\theta + i\pi) =  \frac{F_\text{min,sinh-Gordon}(\theta + i\pi)}{ \cosh (\theta/2) } . \]
016 * 
017 *  
018 */
019public class SinhIsingModel extends IntegrableModel
020{
021    private SinhGordonModel sg;
022    
023    public SinhIsingModel(final double b) {
024        sg = new SinhGordonModel(b);
025    }
026
027    @Override
028    public double FminIpi(double theta) {
029        return sg.FminIpi(theta) / Math.cosh(theta/2.0);
030    }
031    
032}