Remove thermal mass (#352)

* removed thermal mass from particle.py and inert doublet model

* fixed conftest

* removed thermal mass from singletZ2

* removed thermal mass from ManySinglets, Yukawa and SM

* Removed the question about msqThermal in the FAQ

* Fixed line numbers in first example

---------

Co-authored-by: Benoit Laurent <benoit.laurent96@gmail.com>
Co-authored-by: Oliver Gould <oliver.gould@nottingham.ac.uk>

Author: 3 people

Models/InertDoubletModel/inertDoubletModel.py

@@ -125,15 +125,11 @@ def topMsqVacuum(fields: Fields) -> Fields:
         def topMsqDerivative(fields: Fields) -> Fields:
             return self.modelParameters["yt"] ** 2 * fields.getField(0)
 
-        def topMsqThermal(T: float) -> float:
-            return self.modelParameters["g3"] ** 2 * T**2 / 6.0
-
         topQuarkL = Particle(
             name="TopL",
             index=0,
             msqVacuum=topMsqVacuum,
             msqDerivative=topMsqDerivative,
-            msqThermal=topMsqThermal,
             statistics="Fermion",
             totalDOFs=6,
         )
@@ -144,7 +140,6 @@ def topMsqThermal(T: float) -> float:
             index=1,
             msqVacuum=topMsqVacuum,
             msqDerivative=topMsqDerivative,
-            msqThermal=topMsqThermal,
             statistics="Fermion",
             totalDOFs=6,
         )
@@ -157,15 +152,11 @@ def WMsqVacuum(fields: Fields) -> Fields:  # pylint: disable=invalid-name
         def WMsqDerivative(fields: Fields) -> Fields:  # pylint: disable=invalid-name
             return self.modelParameters["g2"] ** 2 * fields.getField(0) / 2
 
-        def WMsqThermal(T: float) -> float:  # pylint: disable=invalid-name
-            return self.modelParameters["g2"] ** 2 * T**2 * 11.0 / 6.0
-
         wBoson = Particle(
             name="W",
             index=4,
             msqVacuum=WMsqVacuum,
             msqDerivative=WMsqDerivative,
-            msqThermal=WMsqThermal,
             statistics="Boson",
             totalDOFs=9,
         )
@@ -177,16 +168,12 @@ def heavyScalarMsqVacuum(fields: Fields) -> Fields:
 
         def heavyScalarMsqDerivative(fields: Fields) -> Fields:
             return self.modelParameters["lambda3"]*fields.getField(0)
-
-        def heavyScalarThermal(T: float) -> float:
-            return self.modelParameters["lambda3"] * T**2 / 24.0
 
         heavyScalar = Particle(
             name="A",
             index=6,
             msqVacuum=heavyScalarMsqVacuum,
             msqDerivative=heavyScalarMsqDerivative,
-            msqThermal=heavyScalarThermal,
             statistics="Boson",
             totalDOFs=3,
         )

Models/ManySinglets/manySinglets.py

@@ -123,15 +123,11 @@ def topMsqDerivative(fields: Fields) -> Fields:
                 ]
             )
 
-        def topMsqThermal(T: float) -> float:
-            return self.modelParameters["g3"] ** 2 * T**2 / 6.0
-
         topQuark = Particle(
             "top",
             index=0,
             msqVacuum=topMsqVacuum,
             msqDerivative=topMsqDerivative,
-            msqThermal=topMsqThermal,
             statistics="Fermion",
             totalDOFs=12,
         )

Models/SingletStandardModel_Z2/singletStandardModelZ2.py

@@ -130,15 +130,11 @@ def topMsqDerivative(fields: Fields) -> Fields:
                 [fields.getField(0), 0 * fields.getField(1)]
             )
 
-        def topMsqThermal(T: float) -> float:
-            return self.modelParameters["g3"] ** 2 * T**2 / 6.0
-
         topQuark = Particle(
             "top",
             index=0,
             msqVacuum=topMsqVacuum,
             msqDerivative=topMsqDerivative,
-            msqThermal=topMsqThermal,
             statistics="Fermion",
             totalDOFs=12,
         )
@@ -155,15 +151,11 @@ def gluonMsqVacuum(fields: Fields) -> Fields:
             def gluonMsqDerivative(fields: Fields) -> Fields:
                 return np.zeros_like(fields)
 
-            def gluonMsqThermal(T: float) -> float:
-                return self.modelParameters["g3"] ** 2 * T**2 * 2.0
-
             gluon = Particle(
                 "gluon",
                 index=1,
                 msqVacuum=gluonMsqVacuum,
                 msqDerivative=gluonMsqDerivative,
-                msqThermal=gluonMsqThermal,
                 statistics="Boson",
                 totalDOFs=16,
             )

Models/StandardModel/standardModel.py

@@ -119,15 +119,11 @@ def topMsqVacuum(fields: Fields) -> Fields:
         def topMsqDerivative(fields: Fields) -> Fields:
             return self.modelParameters["yt"] ** 2 * fields.getField(0)
 
-        def topMsqThermal(T: float) -> float:
-            return self.modelParameters["g3"] ** 2 * T**2 / 6.0
-
         topQuarkL = Particle(
             name="TopL",
             index=0,
             msqVacuum=topMsqVacuum,
             msqDerivative=topMsqDerivative,
-            msqThermal=topMsqThermal,
             statistics="Fermion",
             totalDOFs=6,
         )
@@ -138,7 +134,6 @@ def topMsqThermal(T: float) -> float:
             index=1,
             msqVacuum=topMsqVacuum,
             msqDerivative=topMsqDerivative,
-            msqThermal=topMsqThermal,
             statistics="Fermion",
             totalDOFs=6,
         )
@@ -151,15 +146,11 @@ def WMsqVacuum(fields: Fields) -> Fields:  # pylint: disable=invalid-name
         def WMsqDerivative(fields: Fields) -> Fields:  # pylint: disable=invalid-name
             return self.modelParameters["g2"] ** 2 * fields.getField(0) / 2
 
-        def WMsqThermal(T: float) -> float:  # pylint: disable=invalid-name
-            return self.modelParameters["g2"] ** 2 * T**2 * 3.0 / 5.0
-
         wBoson = Particle(
             name="W",
             index=4,
             msqVacuum=WMsqVacuum,
             msqDerivative=WMsqDerivative,
-            msqThermal=WMsqThermal,
             statistics="Boson",
             totalDOFs=9,
         )

Models/Yukawa/yukawa.py

@@ -64,16 +64,11 @@ def psiMsqDerivative(fields: Fields) -> Fields:
                 )
             )
 
-        # Asymptotic thermal mass (twice the static thermal mass)
-        def psiMsqThermal(T: float) -> float:
-            return 1 / 8 * self.modelParameters["y"] ** 2 * T**2
-
         psiL = Particle(
             "psiL",
             index=1,
             msqVacuum=psiMsqVacuum,
             msqDerivative=psiMsqDerivative,
-            msqThermal=psiMsqThermal,
             statistics="Fermion",
             totalDOFs=2,
         )
@@ -82,7 +77,6 @@ def psiMsqThermal(T: float) -> float:
             index=2,
             msqVacuum=psiMsqVacuum,
             msqDerivative=psiMsqDerivative,
-            msqThermal=psiMsqThermal,
             statistics="Fermion",
             totalDOFs=2,
         )

docs/source/faqs.rst

@@ -99,11 +99,6 @@ Model requirements
     Note that this parameter needs to be of the type Fields. If the particle is in equilibrium the type does not matter, and it
     msqVacuum can simply be set to zero.
 
-- **What is the msqThermal in the Particle defintion?**
-
-    This is the (field-independent) thermal mass of the particle. It is used in the propagator in the matrix elements, and
-    regularizes the IR-divergence in the limit of vanishing Mandelstam variables t and u.
-
 - **How do I cound the totalDOFs in the Particle definition?**
 
     totalDOFs counts the total number of degrees of freedom for a particle species. This includes summing over e.g. spins and colors. 

docs/source/firstExample.rst

@@ -18,7 +18,7 @@ The definition of the Model starts by inheriting from the :py:data:`WallGo.Gener
 
 .. literalinclude:: ../../Models/Yukawa/yukawa.py
    :language: py
-   :lines: 6-90
+   :lines: 6-84
 
 The scalar potential is used both for determining the free energy of homogeneous phases and for the shape and width of the bubble wall. In principle the potentials determining these two phenomena are different, as the former is coarse grained all the way to infinite length scales, while the latter can only consistenly be coarse grained on length scales shorter than the bubble wall width. :footcite:p:`Langer:1974cpa` Nervertheless, at high temperatures and to leading order in powers of the coupling, these two potentials agree.
 
@@ -45,15 +45,15 @@ The implementation in WallGo is as follows: one defines a class, here called :py
 
 .. literalinclude:: ../../Models/Yukawa/yukawa.py
    :language: py
-   :lines: 93-152
+   :lines: 88-146
 
 The initialisation of an :py:data:`WallGo.EffectivePotential` object takes the model parameters and the number of background scalar fields as arguments and stores them for use in evaluating the potential. It is possible to override other member functions when defining :py:data:`WallGo.EffectivePotentialYukawa`, such as the initialisation function, or to add additional member functions and variables, though we haven't done so in this simple example.
 
 Once these two classes have been defined, we can now run WallGo to compute the bubble wall speed.
 
 .. literalinclude:: ../../Models/Yukawa/yukawa.py
    :language: py
-   :lines: 155-216
+   :lines: 149-210
 
 **********
 References

src/WallGo/particle.py

@@ -22,7 +22,6 @@ def __init__(
         index: int,
         msqVacuum: typing.Callable[[Fields | FieldPoint], np.ndarray],
         msqDerivative: typing.Callable[[Fields | FieldPoint], np.ndarray],
-        msqThermal: typing.Callable[[float], float],
         statistics: str,
         totalDOFs: int,
     ) -> None:
@@ -42,10 +41,6 @@ def __init__(
         msqDerivative : function
             Function :math:`d(m_0^2)/d(\phi)`, should take a Fields or FieldPoints
             object and return an array of shape Fields.shape.
-        msqThermal : function
-            Function :math:`m^2_T(T)`, should take a float and return one. The
-            temperature dependent but background field independent part of the
-            effective mass squared.
         statistics : {\"Fermion\", \"Boson\"}
             Particle statistics.
         totalDOFs : int
@@ -63,15 +58,13 @@ def __init__(
             index,
             msqVacuum,
             msqDerivative,
-            msqThermal,
             statistics,
             totalDOFs,
         )
         self.name = name
         self.index = index
         self.msqVacuum = msqVacuum
         self.msqDerivative = msqDerivative
-        self.msqThermal = msqThermal
         self.statistics = statistics
         self.totalDOFs = totalDOFs
 
@@ -81,7 +74,6 @@ def _validateInput(  # pylint: disable=unused-argument
         index: int,
         msqVacuum: typing.Callable[[Fields], np.ndarray],
         msqDerivative: typing.Callable[[Fields], np.ndarray],
-        msqThermal: typing.Callable[[float], float],
         statistics: str,
         totalDOFs: int,
     ) -> None:
@@ -92,13 +84,6 @@ def _validateInput(  # pylint: disable=unused-argument
         # assert isinstance(msqVacuum(fields), float), \
         #    f"msqVacuum({fields}) must return float"
 
-        # LN: comment mass check out to prevent errors at model creation time if no valid params have yet been passed
-        """
-        temperature = 100
-        assert isinstance(
-            msqThermal(temperature), float
-        ), f"msqThermal({temperature}) must return float"
-        """
         if statistics not in Particle.STATISTICS_OPTIONS:
             raise ValueError(f"{statistics=} not in {Particle.STATISTICS_OPTIONS}")
         assert isinstance(totalDOFs, int), "totalDOFs must be an integer"

tests/conftest.py

@@ -53,7 +53,6 @@ def particle() -> WallGo.Particle:
         msqDerivative=lambda fields: np.transpose(
             [fields.getField(0), 0 * fields.getField(1)]
         ),
-        msqThermal=lambda T: 0.1 * T**2,
         statistics="Fermion",
         totalDOFs=12,
     )