acetn.measurement package

Submodules

acetn.measurement.measure module

acetn.measurement.measure.calculate_one_site_measurements(site_list, model, rdm, measurements, measurements_ave)

Calculate the measurements for each site in the iPEPS system, including observables and energy.

Args:

site_list (list): A list of site indices in the iPEPS system. model (Model): The model containing the one-site observables and Hamiltonian. rdm (RDM): The reduced density matrix for the iPEPS system. measurements (dict): A dictionary to store the measurements for each site. measurements_ave (dict): A dictionary to store the averaged measurements.

acetn.measurement.measure.calculate_two_site_measurements(bond_list, model, rdm, measurements, measurements_ave)

Calculate the measurements for each bond in the iPEPS system, including observables and energy.

Args:

bond_list (list): A list of bond indices in the iPEPS system. model (Model): The model containing the two-site observables and Hamiltonian. rdm (RDM): The reduced density matrix for the iPEPS system. measurements (dict): A dictionary to store the measurements for each bond. measurements_ave (dict): A dictionary to store the averaged measurements.

acetn.measurement.measure.measure(ipeps, model)

Perform measurements on the iPEPS system, including both site and bond-level measurements.

Args:

ipeps (Ipeps): The iPEPS tensor network object. model (Model): The model containing Hamiltonians and observables for the measurements.

Returns:

dict: A dictionary containing the averaged measurements, including Energy and other observables.

acetn.measurement.measure.measure_bond_energy(bond, bond_rdm, bond_norm, model)

Measure the energy of a bond in the iPEPS system.

Args:

bond (list): A list representing the bond (e.g., [site1, site2, k]). bond_rdm (Tensor): The reduced density matrix for the bond. bond_norm (float): The normalization factor for the bond. model (Model): The model containing the two-site Hamiltonian for the measurement.

Returns:

float: The energy of the bond.

acetn.measurement.measure.measure_bond_observables(bond, bond_rdm, bond_norm, model, measurements, measurements_ave)

Measure the observables for a bond in the iPEPS system and update the averages.

Args:

bond (list): A list representing the bond (e.g., [site1, site2, k]). bond_rdm (Tensor): The reduced density matrix for the bond. bond_norm (float): The normalization factor for the bond. model (Model): The model containing the two-site observables. measurements (dict): A dictionary to store the measurements for the bond. measurements_ave (dict): A dictionary to store the averaged measurements.

acetn.measurement.measure.measure_one_site(rdm, operator)

Measure the expectation value of a one-site operator with respect to a reduced density matrix.

Args:

rdm (Tensor): The reduced density matrix for the site. operator (Tensor): The one-site operator to measure.

Returns:

float: The expectation value of the operator.

acetn.measurement.measure.measure_site_energy(site, site_rdm, site_norm, model)

Measure the energy of a single site in the iPEPS system.

Args:

site (tuple): The indices (x,y) of the site. site_rdm (Tensor): The reduced density matrix for the site. site_norm (float): The normalization factor for the site. model (Model): The model containing the one-site Hamiltonian for the measurement.

Returns:

float: The energy of the site.

acetn.measurement.measure.measure_site_observables(site, site_rdm, site_norm, model, measurements, measurements_ave)

Measure the observables for a single site in the iPEPS system and update the averages.

Args:

site (int): The index of the site. site_rdm (Tensor): The reduced density matrix for the site. site_norm (float): The normalization factor for the site. model (Model): The model containing the one-site observables. measurements (dict): A dictionary to store the measurements for the site. measurements_ave (dict): A dictionary to store the averaged measurements.

acetn.measurement.measure.measure_two_site(rdm, operator)

Measure the expectation value of a two-site operator with respect to a reduced density matrix.

Args:

rdm (Tensor): The reduced density matrix for the two-site bond. operator (Tensor): The two-site operator to measure.

Returns:

float: The expectation value of the operator.

acetn.measurement.rdm module

class acetn.measurement.rdm.RDM(ipeps)

Bases: object

A class that computes the reduced density matrix (RDM) for a given iPEPS tensor network.

build_bond_rdm(bond)

Builds the reduced density matrix (RDM) for a bond in the iPEPS network.

This method constructs the bond RDM by contracting tensors from two neighboring sites (bond indices) in the iPEPS network and combining them according to a specific contraction scheme.

Args:

bond (list): A list containing three elements, where the first two are site indices and the third is the bond direction.

Returns:

torch.Tensor: The reduced density matrix (RDM) for the specified bond.

build_site_rdm(site)

Builds the reduced density matrix (RDM) for a single site in the iPEPS network.

This method constructs the site RDM by contracting various tensors from the iPEPS object (site tensor ‘A’, corner tensors ‘C’, and edge tensors ‘E’) according to the specified procedure.

Args:

site (tuple): Indices for the site (e.g., a pair of indices in the iPEPS network).

Returns:

torch.Tensor: The reduced density matrix (RDM) for the specified site.

Module contents