Kwant 1.4.1 has been released recently. By now the new version should
be available on all usual channels.
This maintenance release does not introduce any new functionality, but
fixes some backwards compatibility issues that were introduced by 1.4.0.
Most notably, Kwant 1.4.1 is more tolerant to scripts that use the now
deprecated "args" mechanism of passing parameters. For example, value
functions may continue to accept *args or **kwargs as long as the new
"params" parameter-passing mechanism is not used.
Please see the "what's new" document [1] for a detailed list of changes.
[1]
https://kwant-project.org/doc/1/pre/whatsnew/1.4#changes-in-kwant-1-4-1
We are pleased to announce the release of Kwant 1.4, the result of a
year and a half of development.
Highlights of the new release:
* Adding magnetic field to systems, even in complicated cases, is now
specially supported.
* The KPM module can now calculate conductivities.
* The `Qsymm library <https://gitlab.kwant-project.org/qt/qsymm>`_ for
Hamiltonian symmetry analysis has been integrated.
* The handling of system parameters has been improved and optimized.
* Plotting has been improved, most notably through the addition of a
routine that plots densities with interpolation.
* Installing Kwant on Windows is now much easier thanks to Conda
packages.
All these and other improvements that are detailed in the "what's new in
Kwant 1.4" document [1]. The new version is practically 100%
backwards-compatible with scripts written for previous versions of Kwant
1.x.
The following people contributed code to this release:
* Anton Akhmerov
* Paul Clisson
* Christoph Groth
* Thomas Kloss
* Bas Nijholt
* Pablo Pérez Piskunow
* Tómas Örn Rosdahl
* Rafał Skolasiński
* Dániel Varjas
* Joseph Weston
We would like to hear your feedback at kwant-discuss(a)kwant-project.org.
[1] https://kwant-project.org/doc/1.4/pre/whatsnew/1.4
After more than one year of development, we are extremely pleased
to announce the release of Kwant 1.3. Kwant 1.3 supports
* discretizing of continuum Hamiltonians,
* calculating and displaying local densities and currents,
* declaring and using symmetries and conservation laws,
* calculating bulk properties using the kernel polynomial method,
* finalizing builders with multiple translational symmetries,
and has many other improvements that are detailed in the "what's
new in Kwant 1.3" document [1].
The installation instructions [2] have been updated to explain how
to install Kwant 1.3 on computers running GNU/Linux, Mac OS, and
Windows. Note that thanks to the package manager Conda it is now
much easier to install Kwant under Mac OS and on Unix accounts
without root privileges.
The new version is practically 100% backwards-compatible with
scripts written for previous versions of Kwant 1.x.
The Kwant team is happy to welcome Joseph Weston as a member. We
are also grateful to the many contributors without whom this
release would not be nearly as good:
* Jörg Behrmann
* Bas Nijholt
* Michał Nowak
* Viacheslav Ostroukh
* Pablo Pérez Piskunow
* Tómas Örn Rosdahl
* Sebastian Rubbert
* Rafał Skolasiński
* Adrien Sorgniard
We would like to hear your feedback at
kwant-discuss(a)kwant-project.org.
[1] https://kwant-project.org/doc/1.3/pre/whatsnew/1.3
[2] https://kwant-project.org/install
Dear users of Kwant,
At this year’s APS March meeting the core Kwant team held an
“Introduction to Computational Quantum Nanoelectronics” tutorial
[1]. The bulk of the course consisted of hand-on work with
Kwant-powered Jupyter notebooks that contain explanations,
examples and exercises. The tutorial was attended by over 70
people and we received highly positive feedback for it.
The complete set of the tutorial notebooks is now available online
[2]. There is also a link that allows to execute the notebooks
directly in a web browser without installing Kwant locally.
Please feel free to check it out and do not hesitate to spread the
word to anyone who might be interested, especially to people who
are not using Kwant yet.
Regards,
Christoph on behalf of the whole tutorial team
[1] http://www.aps.org/meetings/march/events/tutorials.cfm#t10
[2] http://kwant-project.org/mm16
Hello,
We are happy to announce the release of Kwant 1.2 [1]. Kwant 1.2
is identical to Kwant 1.1 except that it has been updated to run
on Python 3.4 and above. Bugfix releases for the 1.1 and 1.2
series will mirror each other, i.e. 1.1.3 and 1.2.3 will fix the
same bugs.
Starting with Kwant 1.2, all Kwant development will target Python
3. We plan, however, to maintain Python 2 support with the 1.1
series for several years.
At this moment, Kwant 1.2 packages are available [2] for: Debian,
Ubuntu & Windows. Arch Linux and Mac are not ready yet, but will
hopefully follow soon. Please do report any problems (especially
with installation) that you may encounter with the new version.
Thanks to everyone who contributed to this release!
Happy kwanting,
Christoph on behalf of the Kwant team
[1] http://kwant-project.org/doc/1/pre/whatsnew/1.2
[2] http://kwant-project.org/install
Dear all,
This is an announcement for an APS March meeting 2016 tutorial
that will feature Kwant. It can be also found online:
http://www.aps.org/meetings/march/events/tutorials.cfm#t10
Please spread the word to anyone who might be interested.
Christoph
Tutorial #10: Introduction to Computational Quantum
Nanoelectronics
Quantum nanoelectronics deals with the physics of small (< 1 μm)
and/or cold (down to ~10 mK) objects connected to the macroscopic
world through electrodes or gates. A central question at the core
of this field is how quantum effects can be observed and
manipulated through the macroscopic measuring apparatus. In this
tutorial, we will give a pedagogical introduction to the field. We
will start with an introduction to the main theoretical concepts
and a review of some seminal experiments. The central part of the
tutorial will be devoted to practical training on numerical
calculations: we will demonstrate how researchers can simply setup
their own models and perform their own calculations. These
calculations can be used for theoretical predictions, to explain
experimental data or even to assist the conception of device
design.
The numerical part of the lecture is based on the Python
programming language and the Kwant package. No particular
background in programming is needed.
Topics
• Scattering theory of transport, Landauer formula for the
conductance
• Continuous and discrete models (effective mass, Dirac equation,
fermion doubling theorem)
• Electronic interference effects (Aharonov-Bohm effect,
universal conductance fluctuations)
• Topological matter, quantum Hall effect
• Time-resolved nanoelectronics
• Numerical calculations with Python
• Hands-on tutorial on Kwant
• Practical example of the modeling of an experiment
When?
Sunday, March 13, 2016
1:30 p.m. - 5:30 p.m.
Who Should Attend?
PhDs, postdocs, and faculty (both experimentalists and theorists)
interested in calculating the transport properties of quantum
nano-systems (nanowires, semiconducting heterostructures,
graphene, topological insulators…). We particularly encourage
participation of experimentalists wanting to develop their own
modeling of their experiments. Basic knowledge of quantum
mechanics, statistical physics and condensed matter would help to
fully benefit from the tutorial.
Organizer
Christoph Groth, CEA Grenoble, France
Instructors
• Anton Akhmerov, TU Delft, Netherlands
• Christoph Groth, CEA Grenoble, France
• Xavier Waintal, CEA Grenoble, France
• Michael Wimmer, TU Delft, Netherlands
Hello,
We are happy to announce the release of Kwant 1.1. The
user-visible changes are:
• Harmonize Bands with modes
• New option add_cells of attach_lead
• New method conductance_matrix
• Deduction of transmission probabilities
• Clearer error messages
• New option pos_transform of map
See [1] for details. There is nothing spectacular here, but
particularly the improved error messages should make work with
Kwant more pleasant. There was also substantial work “under the
hood” that will allow us to release new versions with much less
effort in the future.
Full backward compatibility is the aim for all Kwant releases that
share the same major version. Thus, all Kwant 1.0 scripts should
continue to work with Kwant 1.1.
Kwant 1.1 packages are available right now for Debian, Ubuntu, and
Windows. They should be available soon for Mac OS & Arch Linux.
Please let us know if you experience any problems.
The plan is that 1.1 will be the last Kwant release for Python 2
and we switch development to Python 3. There should be soon a
Kwant 1.2 that will be identical to 1.1 except that it will use
Python 3. (Do not worry if you have to keep using Python 2: we
plan to maintain Kwant 1.1 for several years.)
Thanks to everyone who contributed to this release!
Happy kwanting,
Christoph on behalf of the Kwant team
[1] http://kwant-project.org/doc/1.1/pre/whatsnew/1.1
Hello,
We are happy to announce the release of Kwant 1.1. The
user-visible changes are:
• Harmonize Bands with modes
• New option add_cells of attach_lead
• New method conductance_matrix
• Deduction of transmission probabilities
• Clearer error messages
• New option pos_transform of map
See [1] for details. There is nothing spectacular here, but
particularly the improved error messages should make work with
Kwant more pleasant. There was also substantial work “under the
hood” that will allow us to release new versions with much less
effort in the future.
Full backward compatibility is the aim for all Kwant releases that
share the same major version. Thus, all Kwant 1.0 scripts should
continue to work with Kwant 1.1.
Kwant 1.1 packages are available right now for Debian, Ubuntu, and
Windows. They should be available soon for Mac OS & Arch Linux.
Please let us know if you experience any problems.
The plan is that 1.1 will be the last Kwant release for Python 2
and we switch development to Python 3. There should be soon a
Kwant 1.2 that will be identical to 1.1 except that it will use
Python 3. (Do not worry if you have to keep using Python 2: we
plan to maintain Kwant 1.1 for several years.)
Thanks to everyone who contributed to this release!
Happy kwanting,
Christoph on behalf of the Kwant team
[1] http://kwant-project.org/doc/1.1/pre/whatsnew/1.1
Dear all,
Please take note of this announcement and forward it to anyone who
might be interested. Thank you.
This summer/fall we are going to hire two PhD students to work
with us on new computational approaches to quantum
transport. Candidates should have a strong background in
theoretical physics (ideally condensed matter / quantum transport)
as well as experience in software design and development.
Each PhD project will consist of three overlapping phases:
(1) Prototyping of a new computational approach for quantum
transport problems.
(2) Implementation of the new approach within the framework of the
Kwant code [1].
(3) Application of the newly gained capabilities to unsolved
physical problems, in close collaboration with experts in the
particular fields.
The two subjects are introduced in some detail at the bottom of
this message.
The research will take place at the Institute for Nanoscience and
Cryogenics (INAC) of CEA Grenoble (France) over the course of
three years under the supervision of Christoph Groth and Xavier
Waintal in close collaboration with Michael Wimmer and Anton
Akhmerov of Delft University of Technology (Netherlands).
The city of Grenoble offers a superb combination of a rich
international scientific environment with a unique natural and
cultural setting. Grenoble is home to a vibrant nanoscience
research community [2], several international research
institutions (ESRF synchrotron, ILL neutron source, and others)
and 60,000 university students. The city is literally surrounded
by the French alps that offer numerous possibilities for outdoor
activities.
Interested candidates are invited to send an application to
Christoph Groth [3] with the subject “PhD application Kwant 2015”.
Applications should include:
• a CV,
• Email addresses of persons that can be asked for a
recommendation,
• an example of theoretical physical work done by the applicant
(e.g. a project, or a master thesis),
Applicants are invited to also provide the source code of a
program that highlights their software engineering experience.
Sincerely
Christoph Groth and Xavier Waintal
[1] http://kwant-project.org/
[2] http://www.fondation-nanosciences.fr/RTRA/en/14/vocation.html
[3] mailto:christoph.groth@cea.fr
Subject 1: Scalable electrostatics computations
Both single-particle simulations of quantum nanoelectronics and
pure electrostatics simulations are a standard problem. However,
in order to accurately simulate complex quantum systems, one needs
to combine both approaches. This transforms the linear
electrostatic problem into a non-linear integro-differential
system of equations with rapidly growing complexity. Current
approaches at exactly solving the combined problem are limited to
small systems of around 10 nanometers in linear size. Advancing
the state of the art is becoming increasingly important to improve
our understanding of modern experiments (e.g. spin qubits,
mesoscale transport).
Subject 2: Multidimensional scattering
Traditionally, quantum transport codes have focused on the 1-d
scattering problem: a finite scattering region with attached
semi-infinite quasi-1-d electrodes. While this suffices to
calculate the basic experimental observables (for example
conductance), solving the more general n-dimensional case would
allow to
• characterize disordered materials with a non-spherical band
structure,
• calculate transport properties of crystallographic defects,
• treat hybrid systems with different dimensionalities (e.g. a 1-d
nanowire coupled to a 3-d superconductor).
The first two capabilities would greatly aid in the analysis of
realistic systems and materials that in practice contain disorder,
dislocations and impurities. The last capability would be highly
valuable for example for studies of Majorana fermions.
Dear all,
We have prepared a short (5 min) anonymous survey for users of
Kwant. Please consider helping us by filling it out and do not
hesitate to spread the word to others who might not be on this
list.
The survey is linked from the top of http://kwant-project.org/.
It can be also accessed directly at
http://kwant-project.org/2015-survey.
Thanks, your feedback is highly appreciated.
Christoph on behalf of the authors of Kwant