From f50cb43a1e63f73d03f4bd1c7c5075fd1410029d Mon Sep 17 00:00:00 2001
From: Joseph Weston <joseph@weston.cloud>
Date: Tue, 22 Jan 2019 15:10:48 +0100
Subject: [PATCH] correct magnetic field units
Magnetic fields are now expressed in units of magnetic flux quantum
per unit area.
---
kwant/physics/gauge.py | 5 ++++-
kwant/physics/tests/test_gauge.py | 2 +-
2 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/kwant/physics/gauge.py b/kwant/physics/gauge.py
index 79682f6a..b120df8a 100644
--- a/kwant/physics/gauge.py
+++ b/kwant/physics/gauge.py
@@ -787,7 +787,7 @@ def calculate_phases(loops, pos, previous_phase, flux):
for loop in loops:
tail, head = loop[-1], loop[0]
integral = flux([pos(p) for p in loop])
- phase = np.exp(2j * np.pi * integral)
+ phase = np.exp(1j * np.pi * integral)
phases[tail, head] = phase / previous_phase(phases, loop)
return phases
@@ -1001,6 +1001,9 @@ class magnetic_gauge:
If callable, takes a position and returns the
magnetic field at that position. Can be a scalar if
the system is 1D or 2D, otherwise must be a vector.
+ Magnetic field is expressed in units :math:`φ₀ / l²`,
+ where :math:`φ₀` is the magnetic flux quantum and
+ :math:`l` is the unit of length.
*lead_fields : scalar, vector or callable
The magnetic fields to apply to each of the leads, in
the same format as 'syst_field'. In addition, if a callable
diff --git a/kwant/physics/tests/test_gauge.py b/kwant/physics/tests/test_gauge.py
index 510259d4..9798a82a 100644
--- a/kwant/physics/tests/test_gauge.py
+++ b/kwant/physics/tests/test_gauge.py
@@ -211,7 +211,7 @@ def _test_phase_loops(syst, phases, loops):
for loop_kind, loop_flux in loops:
for loop in available_loops(syst, loop_kind):
loop_phase = np.prod([phases(a, b) for a, b in loop_to_links(loop)])
- expected_loop_phase = np.exp(2j * np.pi * loop_flux)
+ expected_loop_phase = np.exp(1j * np.pi * loop_flux)
assert np.isclose(loop_phase, expected_loop_phase)
--
GitLab