News on ALF

User Workshop 2026

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Sat, 17 Jan 2026 00:00:00 +0000

We’re pleased to confirm the forth edition of our biennial ALF User Workshop!

Save the date:

October 5th to October 9th

Where:

Hybrid: we plan ALF Workshop 2026 as a hybrid event, taking place in Würzburg – Germany and online.

Its program will include hands-on tutorials and workshop projects, as well as deep-dive talks by participants and invited speakers — there will be something for beginners and experienced researchers alike.

Package reference publication updated

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Thu, 27 Nov 2025 00:00:00 +0000

After some time in the works, ALF’s reference documentation, published in SciPost Physics Codebases has been updated:

ALF Collaboration, The ALF (Algorithms for Lattice Fermions) project release 2.4. Documentation for the auxiliary-field quantum Monte Carlo code. SciPost Phys. Codebases 1-v2.4 (2025). https://doi.org/10.21468/SciPostPhysCodeb.1-v2.4

Notice the current release of the package is ALF 2.6 and we recommend the latest, development version of the code for the latest features and bug fixes.

ALF 2.6 released

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Wed, 05 Nov 2025 00:00:00 +0000

The latest stable version of the package is now ALF 2.6.

Major improvements have been made to the package’s maximum entropy method (MaxEnt), including:

an implementation of the classic, Bayesian-based MaxEnt, besides the standard stochastic MaxEnt
facilities for the easy calculation of quantities such as susceptibilities and quantum Fisher information

An important internal change is the Hubbard Stratonovich fields now being implemented as complex variables instead of real — notice this is a compatibility breaking change.

ALF Mailing List

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Sat, 27 Sep 2025 00:00:00 +0000

ALF now offers a mailing list, hosted by the German Research Network (DFN), and you can subscribe here:
https://www.listserv.dfn.de/sympa/info/jmu-alf-qmc.

It’s a new channel, open to anyone with an email account, through which you can receive announcements, news, inquiries and much more related to the ALF/pyALF packages.

Helmholtz' HiRSE support

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Thu, 29 Aug 2024 00:00:00 +0000

The Helmholtz Platform for Research Software Engineering (HiRSE) is promoting ALF as part of their HiRSE Code Promotion for projects with substantial German participation.

Thank you for your support!

Their ALF slide is also available as a PDF.

User Workshop 2024

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Sat, 17 Aug 2024 00:00:00 +0000

Last month we hosted in Würzburg, Germany the 3rd iteration of the ALF Workshop. Being offered for the first time in a hybrid format, the conference was quite productive, and also challenging, fun and tasty! Check a few pictures in the event’s website (see if you can catch the throwable cubic blue microphone in the air):
https://alfworkshop2024.sciencesconf.org/resource/gallery/id/6

The conference also provided a few interesting additions to the “Quantum Matter Talks” series in our YouTube channel:
https://www.youtube.com/playlist?list=PLGG-0KzRqw_giA44UW-igqKWndam7olrW
as well as updates to the “ALF Basics” playlist:
https://www.youtube.com/playlist?list=PLGG-0KzRqw_jO7CcLdOToQvmF3npdPp-i

User Workshop 2024

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Tue, 09 Apr 2024 00:00:00 +0000

ALF User Workshop is back for its third editon: ALF Workshop 2024!

Registrations are already open: https://alfworkshop2024.sciencesconf.org/.

The event will take place in a hybrid format with both in-person and online sessions to be held simultaneously from 15/July/2024 to 19/July/2024 and is aimed at both beginners and advanced users. A detailed program is not yet available, but it will include:

Getting to Know ALF: A tutorial (basic and advanced) on using ALF.
ALF in Production: Workgroup projects and advanced features.
New developments in lattice fermion simulations: Talks by workshop participants

Whether you’d like to learn the basics of ALF, or could use some help with implementing your own Hamiltonian or measurement, this workshop puts the whole team at your disposal.

ALF 2.5 released

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Mon, 05 Jun 2023 00:00:00 +0000

The latest stable version of the package is now ALF 2.5.

The main improvements with respect to 2.4 are:

Better handling of errors.
Improved, automatic compilation of HDF5.
Safer restart function.

With respect to the latter point: as of ALF 2.5 a file named RUNNING is generated in each run directory and is deleted upon successful completion of the run. Restart is not allowed if the file RUNNING is not present.

ALF 2.4 released

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Tue, 29 Nov 2022 00:00:00 +0000

The latest stable version of the package is now ALF 2.4.

The main improvements with respect to 2.3 are:

The availability of the numerical libraries Lapack and BLAS is now automatically tested by the installation configuration script configure.sh (issue 219).
Symmetries between flavors can now be leveraged to a speed-up of a factor \(N_\text{fl}\)^*.

^{* In the ALF code, the flavor index refers to degrees of freedom that are block diagonal. For example, for the Hubbard model with the Hubbard-Stratonovich transformation that couples to the \(z\)-component of the magnetization, the flavor index corresponds to the spin index. In many cases, there is a symmetry between different flavors, and one can now implement this with ALF 2.4. The speedup of a factor \(N_\text{fl}\) makes it definitely worth it making use of whenever possible.}

Presentation on FAIR data and ALF

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Fri, 11 Nov 2022 00:00:00 +0000

Check our new video: FAIR data & ALF.

We make the case for data management in science, present the concept of FAIR data, and report on the current status of the integration of ALF into the open materials repository NOMAD.

New ALF Reference Paper

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Tue, 30 Aug 2022 00:00:00 +0000

After five years and considerable development effort, ALF’s reference paper got its due update: As the very first paper in SciPost Physics Codebases!

The ALF (Algorithms for Lattice Fermions) project release 2.0. Documentation for the auxiliary-field quantum Monte Carlo code, SciPost Phys. Codebases 1 (2022)
https://scipost.org/SciPostPhysCodeb.1.

Please cite this paper when acknowledging ALF.

Updates to our latest release, ALF 2.3, should follow soon.

BiBTeX

ALF YouTube Channel

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Tue, 02 Aug 2022 00:00:00 +0000

We now have a new home for our videos, where we can better organize them and where they are more easily findable: ALF’s YouTube channel.

Whether you’re more interested in QMC Research talks, or in taking a deep dive into ALF’s code or feel like revisiting our 2020 or 2022 User Workshops, check it out – and don’t forget to subscribe.

ALF 2.3 released

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Fri, 24 Jun 2022 00:00:00 +0000

The latest stable version of the package is now ALF 2.3.

The main improvements with respect to 2.2 are:

Automatically write all parameters to the HDF5 file by parsing the Hamiltonian files and also check that the parameters are identical when resuming a previous run (issue 196).
The necessary numerical libraries are now tested by the installation script (issue 219).
Improved code modularity (issue 223).
Additional error message: warning for checkerboard decomposition on odd-sized lattices (bug 207).
Solved other bugs: 209, 217 and 221.

Notice that, due to this changes, this release is not strictly backwards compatible and the following must be watched:

ALF 2022 concluded

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Mon, 21 Feb 2022 00:00:00 +0000

Last week we concluded the 2022 ALF User Workshop, where the participants could try the latest features of ALF and pyALF.

Links to the event presentations slides and recordings can be found here.

This week of intense work was capped by a very profitable discussion session (picture below). Thank you all!

User Workshop 2022

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Tue, 21 Dec 2021 00:00:00 +0000

The program, also in PDF format, is now available:

As well as our poster (PDF):

User Workshop 2022

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Tue, 14 Dec 2021 00:00:00 +0000

We are glad to announce the second ALF User Workshop: ALF Workshop 2022.

Registrations are already open: https://alfworkshop2022.sciencesconf.org/.

The event will take place online from 14/Feb/2022 to 18/Feb/2022 and is aimed at both beginners and advanced users. A detailed program is not yet available, but it will include:

hands-on sessions with ALF
presentations: QMC theoretical basis, ALF particulars, and recent results
contributed talks by workshop participants

Whether you’d like to learn the basics of ALF, or could use some help with implementing your own Hamiltonian or measurement, this workshop puts the whole team at your disposal.

ALF 2.2 released

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Tue, 07 Dec 2021 00:00:00 +0000

The latest stable version of the package is now ALF 2.2.

The main improvements with respect to 2.1 are:

HDF5 data format is supported (see documentation Sec. 5.7.2, 6.2, 6.3)
bond multiplicity is automatically taken care of by the code

To use HDF5 you’ll need to recompile the package.

Notice that, due to this changes, this release is not strictly backwards compatible:

the argument DEVEL/DEVELOPMENT is no longer a MACHINE name, but an optional switch in script configure.sh
and Hopping_Matrix_Type%Multiplicity is now a private member

Check the CHANGELOG and documentation for further details.

New ALF poster

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Thu, 02 Sep 2021 00:00:00 +0000

Check out our latest poster, created for the FOR1807 International Conference.

You can download it in both PNG and PDF formats, as well as the summary slide for the 2-minute poster slam session.

ALF 2.1 released

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Wed, 23 Jun 2021 00:00:00 +0000

The latest stable version of the package is now ALF 2.1.

The main change from 2.0 is under the hood:

Hamiltonians are now written as submodules of Hamiltonian_main_mod, using the class ham_base, which contains all the stuff common to Hamiltonians - a more economical, object oriented approach that’s a time saver and better structures the code.

Notice that, due to this change, this release is not backwards compatible: check its CHANGELOG and documentation for details and the modifications necessary to adapt existing Hamiltonians to ALF 2.1.

ALF Discord server launched

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Thu, 17 Jun 2021 00:00:00 +0000

This is a new space where developers, users and anyone else interested in ALF can interact via chat, call and video call. Feel free to ask questions about the code, discuss physics or simply chat.

You can join or recommend it to anyone using the link: https://discord.gg/VppWWEPMHa.

pyALF gets own funding

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Mon, 19 Apr 2021 00:00:00 +0000

Great news:

The Unitary Fund awarded us a microgrant for improving ALF’s python interface, pyALF.

ALF 2020 a success

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Sun, 11 Oct 2020 00:00:00 +0000

We just concluded our first ALF User Workshop. After this intense and rewarding week, some additional 50+ researchers can now do QMC simulations using ALF and pyALF in their own machines with many having already started producing their own results.

Being forced into virtual rooms by the pandemic, we faced challenges such as wide time zone differences, but could count with more than twice as many participants as initially planned and, as a by-product of the online conference, we produced a number of video lectures, which will soon be publicly online.

Workshop Program

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Mon, 21 Sep 2020 00:00:00 +0000

The updated program for the ALF User Workshop (05/Oct - 09/Oct) is out!

Please check the Conference’s Website for more information and registering.

The program is also available in the PDF format.

Postponed to October

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Thu, 21 May 2020 00:00:00 +0000

Due to organizational issues we are postponing the ALF User Workshop to:
5th - 9th of October 2020

Please check the Conference’s Website for registering and further information.

Sponsors

To be held online

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Tue, 21 Apr 2020 00:00:00 +0000

Due to the travel disruption caused by the COVID-19 epidemic, the ALF User Workshop will be held online!

Please check the Conference’s Website for registering and further information.

Sponsors

Deadlines Extended

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Tue, 03 Mar 2020 00:00:00 +0000

Registrations for the ALF User Workshop have been extended!

Registration: until 29/May/2020.
Travel assistance request: until 18/May/2020.

Please check the Conference’s Website for registering and further information.

Sponsors

Workshop Poster

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Fri, 24 Jan 2020 00:00:00 +0000

Visit the Conference’s Website for registering (deadline: 29/May/2020).

The poster is also available in the PDF format.

Workshop Program

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Fri, 20 Dec 2019 00:00:00 +0000

The tentative program for the ALF User Workshop (26/Jun - 02/Jul) is out!

Please check the Conference’s Website for registering (deadline: 29/May/2020).

The program is also available in the PDF format.

Registrations Open

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Fri, 15 Nov 2019 00:00:00 +0000

Registrations for the first ALF User Workshop are now open!

Please check the Conference’s Website.

The event will take place from 26/Jun/2020 to 02/Jul/2020 at the University of Würzburg and is aimed at both beginners and advanced users. A detailed program is not yet available, but it will include hands-on sessions with ALF and a few presentations on the QMC theoretical basis and recent results obtained with ALF.

Sponsors

User Workshop

tp1-alf@uni-wuerzburg.de (ALF Collaboration) — Sat, 19 Oct 2019 00:00:00 +0000

We are glad to announce that we have started the preparations for our first ALF User Workshop!

The event will take place next summer at the University of Würzburg and is aimed at both beginners and advanced users. A detailed program is not yet available, but it will include hands-on sessions with ALF and a few presentations on the QMC theoretical basis and recent results obtained with ALF.

Please reserve the period 26/Jun/2020 - 02/Jul/2020 and stay tuned.