# Disentangler¶

Inheritance Diagram

Methods

 Disentangler.__init__(parent) Initialize self.
class tenpy.algorithms.purification_tebd.Disentangler(parent)[source]

Bases: object

Prototype for a disentangler. Trivial, does nothing.

In purification, we write $$\rho_P = Tr_Q{|\psi_{P,Q}><\psi_{P,Q}|}$$. Thus, we can actually apply any unitary to the auxiliar Q space of $$|\psi>$$ without changing the physical expectation values.

Note

We have to apply the same unitary to the ‘bra’ and ‘ket’ used for expectation values / correlation functions!

However, the unitary can strongly influence the entanglement structure of $$|\psi>$$. Therefore, the PurificationTEBD includes a hook in PurificationTEBD.update_bond() (and similar methods) to find and apply a disentangling unitary to the auxiliar indices of a two-site wave function by calling (__call__ method) a Disentangler.

This class is a ‘trivial’ disentangler which does nothing to the two-site wave function; derived classes use different strategies to find various disentanglers.

Parameters

parent (Engine) – The parent class calling the disentangler.

parent

The parent class calling the disentangler.

Type

Engine