kwant.lattice.
TranslationalSymmetry
(*periods)[source]¶Bases: kwant.builder.Symmetry
A translational symmetry defined in real space.
An alias exists for this common name: kwant.TranslationalSymmetry
.
Group elements of this symmetry are integer tuples of appropriate length.
Parameters:  p0, p1, p2, … : sequences of real numbers


Notes
This symmetry automatically chooses the fundamental domain for each new
SiteFamily it encounters. If this site family does not correspond to a
Bravais lattice, or if it does not have a commensurate period, an error is
produced. A certain flexibility in choice of the fundamental domain can be
achieved by calling manually the add_site_family
method and providing it
the other_vectors parameter.
The fundamental domain for hoppings are all hoppings (a, b)
with site
a in fundamental domain of sites.
Methods
add_site_family
(fam, other_vectors=None)[source]¶Select a fundamental domain for site family and cache associated data.
Parameters:  fam : SiteFamily
other_vectors : 2d arraylike of integers


Raises:  KeyError
ValueError

has_subgroup
(other)[source]¶Test whether self has the subgroup other…
or, in other words, whether other is a subgroup of self. The reason why this is the abstract method (and not is_subgroup) is that in general it’s not possible for a subgroup to know its supergroups.
reversed
()[source]¶Return a reversed copy of the symmetry.
The resulting symmetry has all the period vectors opposite to the original and an identical fundamental domain.
subgroup
(*generators)[source]¶Return the subgroup generated by a sequence of group elements.
Parameters:  *generators: sequence of int


to_fd
(a, b=None)[source]¶Map a site or hopping to the fundamental domain.
If b
is None, return a site equivalent to a
within the
fundamental domain. Otherwise, return a hopping equivalent to (a,
b)
but where the first element belongs to the fundamental domain.
Equivalent to self.act(self.which(a), a, b).
which
(site)[source]¶Calculate the domain of the site.
Return the group element whose action on a certain site from the
fundamental domain will result in the given site
.
Attributes