FIREToFCTopology
FIREToFCTopology[props, lmoms, emoms]
converts the list
of FIRE propagators props
that depend on the loop momenta
lmoms
and external momenta emoms
into a proper
FCTopology
object.
Use the option Names
to specify the id
of
the resulting topology.
See also
Overview, FIRECreateConfigFile, FIREPrepareStartFile.
Examples
props1 = {p1^2, p2^2, p3^2, (Q - p1 - p2 - p3)^2, (Q - p1 - p2)^2, (Q - p1)^2, (Q - p2)^2, (p1 + p3)^2, (p2 + p3)^2}
{p12,p22,p32,(−p1−p2−p3+Q)2,(−p1−p2+Q)2,(Q−p1)2,(Q−p2)2,(p1+p3)2,(p2+p3)2}
FIREToFCTopology[props1, {p1, p2, p3}, {Q}]
FCTopology(fctopology,{(p12+iη)1,(p22+iη)1,(p32+iη)1,((−p1−p2−p3+Q)2+iη)1,((−p1−p2+Q)2+iη)1,((Q−p1)2+iη)1,((Q−p2)2+iη)1,((p1+p3)2+iη)1,((p2+p3)2+iη)1},{p1,p2,p3},{Q},{},{})
By default the function assumes the standard iη-prescription as in 1/(p2−m2+iη). However, if you are
using “reversed” propagators that are often preferred in FIRE and
FIESTA, then what you have is 1/(−p2+m2−iη), although the propagator is still Minkowskian. In this
case you should use the option EtaSign
and set it to
-1
props2 = {-p1^2 + m^2, -p2^2 + m^2, -p3^2 + m^2, -(-Q + p1 + p2 + p3)^2, -(p1 + p2 - Q)^2, -(p1 - Q)^2, -(p2 - Q)^2, -(p1 + p3)^2, -(p2 + p3)^2}
{m2−p12,m2−p22,m2−p32,−(p1+p2+p3−Q)2,−(p1+p2−Q)2,−(p1−Q)2,−(p2−Q)2,−(p1+p3)2,−(p2+p3)2}
FIREToFCTopology[props2, {p1, p2, p3}, {Q}, EtaSign -> -1, Names -> myTopo]
FCTopology(myTopo,{(−p12+m2−iη)1,(−p22+m2−iη)1,(−p32+m2−iη)1,(−(p1+p2+p3−Q)2−iη)1,(−(p1+p2−Q)2−iη)1,(−(p1−Q)2−iη)1,(−(p2−Q)2−iη)1,(−(p1+p3)2−iη)1,(−(p2+p3)2−iη)1},{p1,p2,p3},{Q},{},{})
Notice that the polynomials in the FIRE propagators should not be
expanded. Otherwise, there is a high chance that the conversion will
fail.
FIREToFCTopology[ExpandAll[props1], {p1, p2, p3}, {Q}]
$Aborted