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Scalar: SU(N) action change to t'Hooft scaling

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This commit is contained in:
Antonin Portelli 2017-09-29 16:09:34 +01:00
parent 482368e9de
commit a021933002
1 changed files with 8 additions and 6 deletions
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14
lib/qcd/action/scalar/ScalarInteractionAction.h
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@ -44,8 +44,9 @@ public:
INHERIT_FIELD_TYPES(Impl); INHERIT_FIELD_TYPES(Impl);
private: private:
RealD mass_square; RealD mass_square;
RealD lambda; RealD lambda;
const unsigned int N = Impl::Group::Dimension;
typedef typename Field::vector_object vobj; typedef typename Field::vector_object vobj;
typedef CartesianStencil<vobj, vobj> Stencil; typedef CartesianStencil<vobj, vobj> Stencil;
@ -85,8 +86,8 @@ public:
static Stencil phiStencil(p._grid, npoint, 0, directions, displacements); static Stencil phiStencil(p._grid, npoint, 0, directions, displacements);
phiStencil.HaloExchange(p, compressor); phiStencil.HaloExchange(p, compressor);
Field action(p._grid), pshift(p._grid), phisquared(p._grid); Field action(p._grid), pshift(p._grid), phisquared(p._grid);
phisquared = p * p; phisquared = p*p;
action = (2.0 * Ndim + mass_square) * phisquared - lambda / 24. * phisquared * phisquared; action = (2.*Ndim + mass_square) * phisquared - phisquared * phisquared;
for (int mu = 0; mu < Ndim; mu++) for (int mu = 0; mu < Ndim; mu++)
{ {
// pshift = Cshift(p, mu, +1); // not efficient, implement with stencils // pshift = Cshift(p, mu, +1); // not efficient, implement with stencils
@ -121,13 +122,13 @@ public:
} }
// NB the trace in the algebra is normalised to 1/2 // NB the trace in the algebra is normalised to 1/2
// minus sign coming from the antihermitian fields // minus sign coming from the antihermitian fields
return -(TensorRemove(sum(trace(action)))).real(); return -(TensorRemove(sum(trace(action)))).real()*N/lambda;
}; };
virtual void deriv(const Field &p, Field &force) virtual void deriv(const Field &p, Field &force)
{ {
assert(p._grid->Nd() == Ndim); assert(p._grid->Nd() == Ndim);
force = (2.0 * Ndim + mass_square) * p - lambda / 12. * p * p * p; force = (2.0 * Ndim + mass_square) * p - 2. * p * p * p;
// move this outside // move this outside
static Stencil phiStencil(p._grid, npoint, 0, directions, displacements); static Stencil phiStencil(p._grid, npoint, 0, directions, displacements);
phiStencil.HaloExchange(p, compressor); phiStencil.HaloExchange(p, compressor);
@ -162,6 +163,7 @@ public:
} }
} }
} }
force *= N/lambda;
} }
}; };