Anouar - #32

…elpers

Adds an overload of conjugate_by_qft(H, W) that applies the QFT only on position sites and uses identity at auxiliary sites. Adds _embed_in_full_sites (identity padding) and _embed_displacement_in_full_sites (all-ones padding, required so inter-sublattice/inter-layer current matrix elements are not zeroed out).

All five bubble pipeline variants (get_bubble_mpo, get_bubble_mpo_cheb2d, get_bubble_mpo_cheb2d_tucker, get_bubble_diag_cheb2d, get_bubble_diag_cheb2d_svd/tucker) now short-circuit P2 = P1 and Tn2 = Tn1 when both Hamiltonians are the same object, halving the most expensive steps for the self-bubble case.

use replaceinds instead of delta contractions in replace_sites
Replaces the MPOin[n] * delta(bra, prime(new)) * delta(ket, new) pattern with replaceinds, which is a metadata-only operation and avoids spurious tensor contractions.

…nductivity_tk and GPU_tk as I am locally playing around with those)

get_C now accepts Lambda= as an ASCII keyword that falls back to the Unicode Λ parameter, easing use from environments without easy Unicode input.