ModePhonon

class sisl.physics.phonon.ModePhonon(state, parent=None, **info)[source]

A mode describing a physical quantity related to phonons

Attributes

dkind The data-type of the state (in str)
dtype Data-type for the state
info
mode
parent
shape Returns the shape of the state
state

Methods

__init__(state[, parent]) Define a state container with a given set of states
change_gauge(gauge) In-place change of the gauge of the mode coefficients
copy() Return a copy (only the state is copied).
iter([asarray]) An iterator looping over the states in this system
norm() Return a vector with the norm of each state \(\sqrt{\langle\psi|\psi\rangle}\)
norm2([sum]) Return a vector with the norm of each state \(\langle\psi|\psi\rangle\)
normalize() Return a normalized state where each state has \(|\psi|^2=1\)
outer([idx]) Return the outer product for the indices idx (or all if None) by \(\sum_i|\psi_i\rangle\langle\psi_i|\)
sub(idx) Return a new state with only the specified states
change_gauge(gauge)

In-place change of the gauge of the mode coefficients

The two gauges are related through:

\[\tilde C_j = e^{i\mathbf k\mathbf r_j} C_j\]

where \(C_j\) belongs to the gauge R and \(\tilde C_j\) is in the gauge r.

Parameters:
gauge : {‘R’, ‘r’}

specify the new gauge for the mode coefficients
copy()

Return a copy (only the state is copied). parent and info are passed by reference

dkind

The data-type of the state (in str)

dtype

Data-type for the state

info
iter(asarray=False)

An iterator looping over the states in this system

Parameters:
asarray: bool, optional

if true the yielded values are the state vectors, i.e. a numpy array. Otherwise an equivalent object is yielded.
Yields:
state : State

a state only containing individual elements, if asarray is false

state : numpy.ndarray

a state only containing individual elements, if asarray is true
mode
norm()

Return a vector with the norm of each state \(\sqrt{\langle\psi|\psi\rangle}\)

Returns:
numpy.ndarray

the normalization for each state
norm2(sum=True)

Return a vector with the norm of each state \(\langle\psi|\psi\rangle\)

Parameters:
sum : bool, optional

if true the summed site square is returned (a vector). For false a matrix with normalization squared per site is returned.
Returns:
numpy.ndarray

the normalization for each state
normalize()

Return a normalized state where each state has \(|\psi|^2=1\)

This is roughly equivalent to:

>>> state = State(np.arange(10))
>>> n = state.norm()
>>> norm_state = State(state.state / n.reshape(-1, 1))
Returns:
State

a new state with all states normalized, otherwise equal to this
outer(idx=None)

Return the outer product for the indices idx (or all if None) by \(\sum_i|\psi_i\rangle\langle\psi_i|\)

Parameters:
idx : int or array_like, optional

only perform an outer product of the specified indices, otherwise all states are used
Returns:
numpy.ndarray

a matrix with the sum of outer state products
parent
shape

Returns the shape of the state

state
sub(idx)

Return a new state with only the specified states

Parameters:
idx : int or array_like

indices that are retained in the returned object
Returns:
State

a new state only containing the requested elements