Applications
We have a few ready-to-use applications for some basic physics calculations. If you make a new application,
please make sure it starts with main_
.
main_getBeta.py
Given a reference scale, \(N_\tau\), and \(T\) in [MeV], this script calculates the corresponding \(\beta\). An example calling is
./main_getTempandSpacing.py --Nt 8 --scale r0 --T 300
main_getTempAndSpacing.py
Given a reference scale, \(N_\tau\), and \(\beta\) value, this script calculates \(T\) in [MeV] and \(a\) in [fm]. An example calling is
./main_getTempandSpacing.py --Nt 8 --beta 6.285 --scale fk
For more details about the scale setting, please look into the reference scales article.
main_HRG_measure.py
The goal of this script is to calculate some observables in the HRG model given some external control parameters, like a range of temperatures with fixed \(\mu_B/T\). By default, this program uses a list of hadrons and resonances created by the HotQCD collaboration called QMHRG2020. You can find this list here:
latqcdtools/physics/HRGtables/hadron_list_ext_strange_2020.txt
A list that includes charmed hadrons and resonances is
latqcdtools/physics/HRGtables/hadron_list_ext_strange_charm_2020.txt
You can choose your hadron list with the --hadron_file
argument. It is also up to you to choose a model; at the moment
the only possibilities are the typical HRG QM
or an excluded volume HRG model EV
. This is specified with
the argument --model
. Finally you need to specify your observable --obs
. If you specify a generalized
susceptibility chi
, you must also pass the \(B\), \(Q\), \(S\), and \(C\) chemical potential derivative orders.
A straightforward usage of this script is, for instance,
./main_HRG_measure.py --obs chi --bqsc 1100 --temperature_range 130:180:0.5 --muB 0.0
main_HRG_LCP.py
In the context of QCD at finite chemical potential, it is interesting to examine systems following a few lines of constant physics (LCPs). The HotQCD collaboration has focused on strangeness-neutral systems, with \(n_Q/n_B=0.4\) (corresponding to gold-gold collisions at RHIC) and \(n_Q/n_B=0.5\) (corresponding to the isospin-symmetric case). This script creates tables of \(\mu_B/T\), \(\mu_Q/T\), and \(\mu_S/T\) (\(\mu_C=0\)) that lie on \(n_S=0\) LCPs like the ones mentioned above. A straightforward usage of this script is, for instance,
./main_HRG_LCP.py --r 0.4 --models QM --T 150
Once you have generated some LCP files, you can also use main_HRG_measure.py
from above to carry out measurements
on them. In such a case, you must pass the LCP file as argument. For instance,
./main_HRG_measure.py --obs chi --bqsc 1100 --LCP_file HRG_LCP_T150.0_r0.5QM
main_plotRatApprox.py
The RHMC of SIMULATeQCD relies on a rational approximation to the fermion determinant. It is useful to see how well this approximation compares with the exact function. This can be checked visually with, for example
./main_plotRatApprox.py in.rational 0.001 0.01
where in.rational
is the rational approximation file, and we use a light quark mass of 0.001 in lattice units
and a strange quark mass of 0.01.
main_HotQCDEoS.py
The paramterization for HotQCD equation of state at \(\mu_B/T = 0\), \(\mu_Q/T = 0\), and \(\mu_S/T = 0\) are given in “Equation of state in ( 2+1 )-flavor QCD, Phys.Rev.D 90 (2014) 094503, (HotQCD Collaboration) A. Bazavov et al.”. The pressure (\(P\)), energy density (\(\epsilon\)) and entropy density (\(s\)) can be obtained from the thermodynamic relations.
./main_HotQCDEoS.py --EosType "fixedmuB" --muBdivT 0.0