Handles graphs for applying wick theorem. In this file lies the algorithm performing Wick contractions, i.e. that finds all different Feynman diagrams (with their numerical factor) that intervenes in a given process (i.e. correlation function). More...

#include "quantumField.h"
#include "fermionFlow.h"

Data Structures
class	mty::wick::Node
	Represents a contractible mty::QuantumField in the context of Wick contraction. More...

class	mty::wick::Vertex
	Represents a Vertex in feynman diagrams, i.e. a set of Nodes at the same space-time point. More...

class	mty::wick::ConnectedComponent
	std::vector of Vertex that represents the connected component of a Graph. A Graph has typically one ConnectedComponent and free Vertices. More...

class	mty::wick::Graph
	Handles wick contractions. A graph contains Vertices, and is able to connect them in all possible ways returning the set of all possible Graph. More...

class	mty::wick::WickCalculator
	Class handling the full application of Wick theorem. Starts from an initial Graph fully disconnected, delegates contraction steps to the Graph class and handles the series of resulting Graphs (eliminates non physical ones, iterates the Graph::contractoinStep()...). More...

Namespaces
	mty
	Namespace of MARTY.

Functions
void	mty::wick::contractNodes (const std::shared_ptr< Node > &node1, const std::shared_ptr< Node > &node2)
	Contracts two Node together, i.e. sets the partner of each node equal to a std::weak_ptr to the other. More...

bool	mty::wick::areDegenerate (const mty::QuantumField &f1, const mty::QuantumField &f2)
	Tells if two mty::QuantumField are degenerate, i.e. have the same value in the contraction sens. They must be the same mty::QuantumField and have the same conjugation property. More...

bool	mty::wick::areExactlyContractible (const mty::QuantumField &f1, const mty::QuantumField &f2)
	Tells if the contraction of two mty::QuantumField is non zero. More...

std::ostream &	mty::wick::operator<< (std::ostream &fout, const std::shared_ptr< Node > &node)
	Overload of the operator<< for Node. More...

bool	mty::wick::operator== (const std::shared_ptr< Node > &A, const std::shared_ptr< Node > &B)
	Overload of operator== for sstd::shared_ptr<Node>. Compares the values of the two pointers. More...

bool	mty::wick::comparePriority (const std::shared_ptr< Node > &A, const std::shared_ptr< Node > &B, const std::vector< csl::Tensor > &foundNodes)

bool	mty::wick::internal_comparePriority (const std::shared_ptr< Node > &A, const std::shared_ptr< Node > &B, const std::vector< csl::Tensor > &foundNodes)

std::vector< mty::QuantumField >	mty::wick::convertExprToFields (const csl::Expr &expr)
	Converts a csl csl::Expr that is just a product of field into a std::vector of mty::QuantumField objects. More...

int	mty::wick::countFermions (std::vector< const mty::QuantumField >::const_iterator begin, std::vector< const mty::QuantumField >::const_iterator end)
	Counts the number of fermions in a std::vector of mty::QuantumField. More...

int	mty::wick::getCommutationSign (const std::vector< mty::QuantumField > &A, std::vector< const mty::QuantumField *> B)
	Computes and returns the sign cost of the commutation of two sets of mty::QuantumField. \( sgn = (-1)^{N_c}\), with \( N_c \) the number of fermion permutations necessary to Transform A to B. More...

int	mty::wick::getCommutationSign (const std::vector< const mty::QuantumField > &A, std::vector< const mty::QuantumField > B)

csl::vector_expr	mty::wick::convertGraphsToCorrelators (const std::vector< std::shared_ptr< Graph >> &diagrams, std::vector< mty::FeynruleMomentum > &witnessMapping, bool ruleMode=true)
	Converts a std::vector of fully connected graphs into a std::vector of expressions (one expression per graph) via Graph::getExpression(). More...

Detailed Description

Handles graphs for applying wick theorem. In this file lies the algorithm performing Wick contractions, i.e. that finds all different Feynman diagrams (with their numerical factor) that intervenes in a given process (i.e. correlation function).

Author: Gregoire Uhlrich

Version: 1.3

Function Documentation

◆ areDegenerate()

bool mty::wick::areDegenerate	(	const mty::QuantumField &	f1,
		const mty::QuantumField &	f2
	)

Tells if two mty::QuantumField are degenerate, i.e. have the same value in the contraction sens. They must be the same mty::QuantumField and have the same conjugation property.

Example: \( \psi^*(X)_{\alpha} \) and \( \psi(Y)_{\beta} \) are contractible together but not degenerate. \( \psi^*(X)_{\alpha} \) and \( \psi^*(Y)_{\beta} \) are not contractible together but are degenerate.

Parameters

f1	First mty::QuantumField to compare.
f2	Second mty::QuantumField to compare.

Returns: True if f1 and f2 are degenerate.; False else.

◆ areExactlyContractible()

bool mty::wick::areExactlyContractible	(	const mty::QuantumField &	f1,
		const mty::QuantumField &	f2
	)

Tells if the contraction of two mty::QuantumField is non zero.

Parameters

f1	First mty::QuantumField in the contraction.
f2	Second mty::QuantumField in the contraction.

Returns: True if the contraction of f1 and f2 is non zero.; False else.

◆ contractNodes()

void mty::wick::contractNodes	(	const std::shared_ptr< Node > &	node1,
		const std::shared_ptr< Node > &	node2
	)

Contracts two Node together, i.e. sets the partner of each node equal to a std::weak_ptr to the other.

Parameters

node1	std::shared_ptr to the first Node.
node2	std::shared_ptr to the second Node.

◆ convertExprToFields()

vector< QuantumField > mty::wick::convertExprToFields ( const csl::Expr & expr )

Converts a csl csl::Expr that is just a product of field into a std::vector of mty::QuantumField objects.

This function raises an error if it finds an object in the product that is neither a mty::QuantumField nor a positive Integer power of mty::QuantumField. If a field appears in a power, it is put as many times in the vector as its integer power.

Parameters

expr	csl::Expr product of quantum fields to convert.

Returns: A std::vector of mty::QuantumField containing all fields in expr.

◆ convertGraphsToCorrelators()

csl::vector_expr mty::wick::convertGraphsToCorrelators	(	const std::vector< std::shared_ptr< Graph >> &	diagrams,
		std::vector< mty::FeynruleMomentum > &	witnessMapping,
		bool	ruleMode = `true`
	)

Converts a std::vector of fully connected graphs into a std::vector of expressions (one expression per graph) via Graph::getExpression().

Parameters

diagrams Fully connected graphs to convert.

Returns: The converted graphs into csl csl::Expr.

◆ countFermions()

int mty::wick::countFermions	(	std::vector< const mty::QuantumField *>::const_iterator	begin,
		std::vector< const mty::QuantumField *>::const_iterator	end
	)

Counts the number of fermions in a std::vector of mty::QuantumField.

Parameters

begin	Begin iterator of the std::vector of mty::QuantumField.
end	End iterator of the std::vector of mty::QuantumField.

Returns: The number of fermions in the vector.

◆ getCommutationSign()

int mty::wick::getCommutationSign	(	const std::vector< mty::QuantumField > &	A,
		std::vector< const mty::QuantumField *>	B
	)

Computes and returns the sign cost of the commutation of two sets of mty::QuantumField. \( sgn = (-1)^{N_c}\), with \( N_c \) the number of fermion permutations necessary to Transform A to B.

Parameters

A	Initial order of fields.
B	Same field content as A but in a different order.

Returns: The sign cost of the permutation of B in order to Transform it into A.

◆ operator<<()

std::ostream& mty::wick::operator<<	(	std::ostream &	fout,
		const std::shared_ptr< Node > &	node
	)

Overload of the operator<< for Node.

Parameters

fout	Output flux.
node	Node to display in a std::shared_ptr.

Returns: The modified flux.

◆ operator==()

bool mty::wick::operator==	(	const std::shared_ptr< Node > &	A,
		const std::shared_ptr< Node > &	B
	)

Overload of operator== for sstd::shared_ptr<Node>. Compares the values of the two pointers.

Parameters

A	First std::shared_ptr to Node to compare.
B	Second std::shared_ptr to Node to compare.

Returns: True if the two pointers point to the same memory location.; False else.

Data Structures

Namespaces

Functions

Detailed Description

Function Documentation

◆ areDegenerate()

◆ areExactlyContractible()

◆ contractNodes()

◆ convertExprToFields()

◆ convertGraphsToCorrelators()

◆ countFermions()

◆ getCommutationSign()

◆ operator<<()

◆ operator==()