From 281711dc83c64ff50caf69b8f6f5030b04ec04fe Mon Sep 17 00:00:00 2001
From: Daniel Varjas <dvarjas@gmail.com>
Date: Sat, 2 Nov 2019 02:14:31 +0100
Subject: [PATCH] aviod conversion between Model and BlochModel in
bloch_hamiltonian
---
qsymm/hamiltonian_generator.py | 30 ++++++++++++++++++------------
1 file changed, 18 insertions(+), 12 deletions(-)
diff --git a/qsymm/hamiltonian_generator.py b/qsymm/hamiltonian_generator.py
index aa94c0f..dc33db4 100644
--- a/qsymm/hamiltonian_generator.py
+++ b/qsymm/hamiltonian_generator.py
@@ -7,7 +7,7 @@ from copy import deepcopy
import tinyarray as ta
from .linalg import matrix_basis, nullspace, sparse_basis, family_to_vectors, rref, allclose
-from .model import Model, BlochModel, _commutative_momenta, e, I
+from .model import Model, BlochModel, BlochCoeff, _commutative_momenta, e, I
from .groups import PointGroupElement, ContinuousGroupGenerator, generate_group
from . import kwant_continuum
@@ -571,6 +571,7 @@ def symmetrize_monomial(monomial, symmetries):
def bloch_family(hopping_vectors, symmetries, norbs, onsites=True,
+ momenta=_commutative_momenta,
symmetrize=True, prettify=True, num_digits=10,
bloch_model=False):
"""Generate a family of symmetric Bloch-Hamiltonians.
@@ -591,7 +592,10 @@ def bloch_family(hopping_vectors, symmetries, norbs, onsites=True,
corresponding to each site.
onsites : bool, default True
Whether to include on-site terms consistent with the symmetry.
- symmetrize : bool
+ momenta : iterable of strings or Sympy symbols
+ Names of momentum variables, default ``['k_x', 'k_y', 'k_z']`` or
+ corresponding sympy symbols.
+ symmetrize : bool, default True
Whether to use the symmetrization strategy. This does not require
a full set of hoppings to start, all symmetry related hoppings
are generated. Otherwise the constraining strategy is used, this does
@@ -670,16 +674,22 @@ def bloch_family(hopping_vectors, symmetries, norbs, onsites=True,
n, m = norbs[a], norbs[b]
block_basis = np.eye(n*m, n*m).reshape((n*m, n, m))
block_basis = np.concatenate((block_basis, 1j*block_basis))
- # Hopping direction in real space
- # Dot product with momentum vector
- phase = sum([coordinate * momentum for coordinate, momentum in
- zip(vec, _commutative_momenta[:dim])])
- factor = e**(I*phase)
+ if bloch_model:
+ bloch_coeff = BlochCoeff(np.array(vec), sympy.sympify(1))
+ else:
+ # Hopping direction in real space
+ # Dot product with momentum vector
+ phase = sum([coordinate * momentum for coordinate, momentum in
+ zip(vec, momenta[:dim])])
+ factor = e**(I*phase)
hopfamily = []
for mat in block_basis:
matrix = np.zeros((N, N), dtype=complex)
matrix[ranges[a], ranges[b]] = mat
- term = Model({factor: matrix}, momenta=('k_x', 'k_y', 'k_z')[:dim])
+ if bloch_model:
+ term = BlochModel({bloch_coeff: matrix}, momenta=momenta[:dim])
+ else:
+ term = Model({factor: matrix}, momenta=momenta[:dim])
term = term + term.T().conj()
hopfamily.append(term)
# If there are conserved quantities, constrain the hopping, it is assumed that
@@ -687,10 +697,6 @@ def bloch_family(hopping_vectors, symmetries, norbs, onsites=True,
if conserved:
hopfamily = constrain_family(conserved, hopfamily)
family.extend(hopfamily)
- # Use BlochModel objects instead of Model.
- if bloch_model:
- family = [BlochModel(member, momenta=member.momenta) for
- member in family]
if symmetrize:
# Make sure that group is generated while keeping track of unitary part.
for g in pg:
--
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