cpc1-HRG-TDep.cpp

Calculates the temperature dependence of HRG thermodynamics at zero chemical potentials.

The calculated quantities include scaled pressure, scaled energy density, scaled entropy density, the 2nd and 4th order baryon number susceptibilities.

Calculations can be done within three different models:

• <config> = 0: Ideal HRG model
• <config> = 1: EV-HRG model with a constant radius parameter r = 0.3 fm for all hadrons (as in 1412.5478)
• <config> = 2: QvdW-HRG with QvdW interactions between baryons only, with parameters being fixed to the nuclear ground state (as in 1609.03975)

Usage:

cpc1HRGTDep <config>

#include <string.h>
#include <fstream>
#include <iostream>
#include <iomanip>
#include <ctime>
#include <cstdio>
 
#include "HRGBase.h"
#include "HRGEV.h"
#include "HRGFit.h"
#include "HRGVDW.h"
 
#include "ThermalFISTConfig.h"
 
using namespace std;
 
#ifdef ThermalFIST_USENAMESPACE
using namespace thermalfist;
#endif
 
 
// Temperature dependence of HRG thermodynamics at \mu = 0
// Three variants of the HRG model: 
// 1. Ideal HRG: <config> = 0
// 2. EV-HRG with constant radius parameter r = 0.3 fm for all hadrons (as in 1412.5478): <config> = 1
// 3. QvdW-HRG with a and b for baryons only, fixed to nuclear ground state (as in 1609.03975): <config> = 2
// Usage: cpc1HRGTDep <config>
int main(int argc, char *argv[])
{
  // Particle list file
  // Here we will use the list from THERMUS-2.3, for comparing the results with THERMUS-2.3
  string listname = string(ThermalFIST_INPUT_FOLDER) + "/list/thermus23/list.dat";
 
  // Alternative: use the default PDG2014 list
  //string listname = string(ThermalFIST_INPUT_FOLDER) + "/list/PDG2014/list.dat";
  
  // Create the hadron list instance and read the list from file
  ThermalParticleSystem TPS(listname);
 
  // Which variant of the HRG model to use
  int config = 0;
 
  // Read config from command line
  if (argc > 1)
    config = atoi(argv[1]);
 
  
  string modeltype; // For output
  
 
  // Pointer to the thermal model instance used in calculations
  ThermalModelBase *model;
 
  
 
  if (config == 0) // Ideal HRG
  {
    model = new ThermalModelIdeal(&TPS);
    
    printf("#Calculating thermodynamics at \\mu = 0 in Id-HRG model\n");
 
    modeltype = "Id-HRG";
  }
  else if (config == 1) // EV-HRG, r = 0.3 fm, to reproduce 1412.5478
  {
    model = new ThermalModelEVDiagonal(&TPS);
    // Set r = 0.3 fm for each hadron in the list
    double rad = 0.3;
    for (int i = 0; i < model->TPS()->ComponentsNumber(); ++i)
      model->SetRadius(i, rad);
 
    printf("#Calculating thermodynamics at \\mu = 0 in EV-HRG model with r = %lf fm\n", rad);
 
    modeltype = "EV-HRG";
  }
  else if (config == 2) // QvdW-HRG, to reproduce 1609.03975
  {
    model = new ThermalModelVDWFull(&TPS);
 
    // vdW parameters, for baryon-baryon, antibaryon-antibaryon ONLY, otherwise zero
    double a = 0.329; // In GeV*fm3
    double b = 3.42;  // In fm3
 
    // Iterate over all pairs of hadron species and set a and b
    for (int i = 0; i < model->TPS()->ComponentsNumber(); ++i) {
      for (int j = 0; j < model->TPS()->ComponentsNumber(); ++j) {
        int B1 = model->TPS()->Particle(i).BaryonCharge(); // Baryon number of 1st species
        int B2 = model->TPS()->Particle(j).BaryonCharge(); // Baryon number of 2nd species
 
        if ((B1 > 0 && B2 > 0) || (B1 < 0 && B2 < 0))  // baryon-baryon or antibaryon-antibaryon
        {
          model->SetAttraction(i, j, a); // Set QvdW attraction
          model->SetVirial(i, j, b);     // Set QvdW repulsion
        }
        else // no vdW interactions for meson-meson, meson-baryon or baryon-anitbaryon pairs
        {
          model->SetAttraction(i, j, 0.);
          model->SetVirial(i, j, 0.);
        }
      }
    }
 
    printf("#Calculating thermodynamics at \\mu = 0 in QvdW-HRG model\n");
 
    modeltype = "QvdW-HRG";
  }
  else // Ideal HRG by default
  {
    model = new ThermalModelIdeal(&TPS);
 
    modeltype = "Id-HRG";
  }
 
  // Use quantum statistics
  model->SetStatistics(true);
  //model->SetStatistics(false);
 
  // Use mass integration over Breit-Wigner shapes in +-2Gamma interval, as in THERMUS
  model->SetUseWidth(ThermalParticle::BWTwoGamma);
  //model->SetUseWidth(ThermalParticle::ZeroWidth);
 
  // Set chemical potentials to zero
  model->SetBaryonChemicalPotential(0.0);
  model->SetElectricChemicalPotential(0.0);
  model->SetStrangenessChemicalPotential(0.0);
  model->SetCharmChemicalPotential(0.0);
  model->FillChemicalPotentials();
 
  
  // Prepare output
  char tmpc[1000];
  sprintf(tmpc, "cpc1.%s.TDep.out", modeltype.c_str());
  FILE *fout = fopen(tmpc, "w");
 
  // Output to screen
  printf("%15s%15s%15s%15s%15s%15s%15s\n",
    "T[MeV]", // Temperature
    "p/T^4",  // Scaled pressure
    "e/T^4",  // Scaled energy density
    "s/T^3",   // Scaled entropy density
    "chi2B",   // Baryon number susceptibility
    "chi4B",   // 4th order baryon cumulant
    "chi2B-chi4B"   // Difference of 2nd and 4th order baryon susceptibilities
  );
 
  // Output to file
  fprintf(fout, "%15s%15s%15s%15s%15s%15s%15s\n",
    "T[MeV]", // Temperature
    "p/T^4",  // Scaled pressure
    "e/T^4",  // Scaled energy density
    "s/T^3",   // Scaled entropy density
    "chi2B",   // Baryon number susceptibility
    "chi4B",   // 4th order baryon cumulant
    "chi2B-chi4B"   // Difference of 2nd and 4th order baryon susceptibilities
  );
 
 
  double wt1 = get_wall_time(); // Timing
 
  int iters = 0; // Number of data points
 
  // Temperature interval, in GeV
  double Tmin = 0.020;
  double Tmax = 0.2001;
  double dT   = 0.001;
 
  for (double T = Tmin; T <= Tmax; T += dT) {
    model->SetTemperature(T);
 
    // Calculates densities, solves all necessary transcendental equations, if necessary
    model->CalculateDensities();
 
    // Output temperature, scale to get the unit of MeV
    printf("%15lf", T * 1000.);
    fprintf(fout, "%15lf", T * 1000.);
 
    // Pressure, in [GeV/fm3]
    double p = model->CalculatePressure();
    // Scaled pressure, pow(xMath::GeVtoifm(), 3) needed to make it dimensionless
    double pT4 = p / pow(T, 4) / pow(xMath::GeVtoifm(), 3);
    printf("%15lf", pT4);
    fprintf(fout, "%15lf", pT4);
 
    // Energy density
    double e = model->CalculateEnergyDensity();
    double eT4 = e / pow(T, 4) / pow(xMath::GeVtoifm(), 3);
    printf("%15lf", eT4);
    fprintf(fout, "%15lf", eT4);
 
    // Entropy density
    double s = model->CalculateEntropyDensity();
    double sT3 = s / pow(T, 3) / pow(xMath::GeVtoifm(), 3);
    printf("%15lf", sT3);
    fprintf(fout, "%15lf", sT3);
 
 
    // Baryon number fluctuations
 
    // Vector containing baryon charge of each species
    vector<double> baryon_charges;
    for (int i = 0; i < model->TPS()->ComponentsNumber(); ++i) {
      baryon_charges.push_back(static_cast<double>(model->TPS()->Particle(i).BaryonCharge()));
    }
 
    // Calculate baryon number cumulants up to 4th order
    vector<double> chiB = model->CalculateChargeFluctuations(baryon_charges, 4);
 
    if (chiB.size() >= 4) {
      // chi2B
      printf("%15E", chiB[1]);
      fprintf(fout, "%15E", chiB[1]);
 
      // chi4B
      printf("%15E", chiB[3]);
      fprintf(fout, "%15E", chiB[3]);
 
      // chi2B - chi4B
      printf("%15E", chiB[1] - chiB[3]);
      fprintf(fout, "%15E", chiB[1] - chiB[3]);
    }
 
    printf("\n");
    fprintf(fout, "\n");
 
    iters++;
 
  }
 
  fclose(fout);
 
  delete model;
  
 
  double wt2 = get_wall_time();
 
  printf("%30s %lf s\n", "Running time:", (wt2 - wt1));
  printf("%30s %lf s\n", "Time per single calculation:", (wt2 - wt1) / iters);
 
  return 0;
}