symop.ccr.algebra.density.expand_word_times_monomial

Expansion of an operator word acting on a monomial from the left.

This module provides a symbolic normal-ordering helper for products of the form

\[W \cdot \hat{M},\]

where \(W\) is an operator word (a finite ordered sequence of ladder operators) and \(\hat{M}\) is a normally-ordered monomial in ladder operators.

The result is returned as a list of ket terms representing the normally-ordered expansion of \(W \hat{M}\).

Functions

expand_word_times_monomial(word, M)

Expand an operator word acting on a monomial from the left.
expand_word_times_monomial(word: Iterable[LadderOp], M: Monomial) → list[KetTerm]

Expand an operator word acting on a monomial from the left.

Computes the normally-ordered expansion of

\[W \cdot \hat{M},\]

where W is a sequence of ladder operators and \(\hat{M}\) is the target monomial.

Internally, this starts from the one-term ket representing \(\hat{M}\) and applies the operators in word one-by-one (right-to-left) using ket_apply_word().

Parameters:

  • word (Iterable[LadderOp]) – Operator word to apply on the left.

  • M (Monomial) – Target monomial.

Returns:

List of normally-ordered ket terms for \(W \hat{M}\).

Return type:

list[KetTerm]