triqs.operators.operators.Operator

class triqs.operators.operators.Operator

Bases: object

Generic many-body operator.

A generic many-body operator \(\hat{O}\) is defined as a linear combination of monomials \(\hat{m}_i\) such that

\[\hat{O} = \sum_{i} a_i \hat{m}_i \; ,\]

where \(a_i\) are real or complex coefficients.

Under the hood, we simply store all individual terms in a map/dictionary with the monomials as keys and the coefficients as values.

Operator-operator and operator-scalar arithmetic is supported such that many-body operators form an algebra over the field of real/complex numbers with an extra addition operation between operators and scalars.

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Dispatched C++ constructor(s).

[1] ()

[2] (x: float | complex)

[3] (x: float | complex, monomial: [CanonicalOpsT])

[1] Default constructor creates a zero many-body operator, i.e. with no terms.

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[2] Construct a many-body operator \(\hat{O} = a \hat{I}\).

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[3] Construct a many-body operator \(\hat{O} = a \hat{m}\).

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Parameters:

xfloat | complex

Coefficient \(a\) of the identity operator \(\hat{I}\).

monomial[CanonicalOpsT]

Monomial \(\hat{m}\).

Attributes

imag	Get a copy of the operator \(\hat{O}\) with the real parts of all monomial coefficients set to zero.
real	Get a copy of the operator \(\hat{O}\) with the imaginary parts of all monomial coefficients set to zero.

Methods

get_monomials	Get the map/dictionary of monomials and their coefficients.
is_almost_zero	Check if the current operator \(\hat{O}\) is close to zero.
is_zero	Check if the current operator \(\hat{O}\) is exactly zero.
make_canonical	Create a many-body operator that represents a single canonical operator \(\hat{c}_{\alpha}\) or
make_fundamental_operator_set	Create a minimal fundamental operator set with all single particle state indices \(\alpha_i\) that