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JSF Workshop on the Fermion Sign Problem (JSF-FSP)

(Peyresq, France, 23–30 July 2023)

Organizing CommitteeParticipantsVenue and Accommodation Contact

Quantum Monte Carlo (QMC) has become a central tool in several research disciplines. It is used, for example, to calculate the structures of atoms, molecules, nuclei, and elementary particles; it is used to calculate the properties of strongly correlated systems in condensed matter with high temperature superconductivity and topological properties prime targets. A common limiting problem shared across this spectrum of applications is the infamous "fermion sign problem" which appears when the statistical weight of a configuration becomes negative (or, worse, complex). Since the partition function is positive definite, it becomes the difference of two very large contributions, those coming from positive statistical weights and those from the negative ones. This results in huge statistical errors and sets severe limits on the size of the systems that can be studied and their temperatures since the severity of the problem increases exponentially with system size and inverse temperature. This problem also depends on the details of the formulation of the QMC algorithm indicating that its roots are mathematical rather than physical.

This problem, with its wide range of physical applications, has attracted the attention of researchers in several fields including condensed matter, nuclear physics, lattice gauge theory, chemistry, and mathematics. Several approaches are being taken to solve the sign problem or at least reduce its severity. These include complex Langevin equation, Lefschetz thimbles, and other reformulations of the path integral used in the QMC.

JSF-FSP will bring together researchers from all these fields to allow for easy exchange of ideas and, so we hope, the emergence of new ones.

Organizing Committee

George Batrouni (chair), Fakher Assaad, Berge Englert
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Participation is by invitation only.
Participants (as of 10 January 2023):

Andrei Alexandru (George Washington University, District of Columbia)
David Ceperley (UIUC, Urbana-Champaign, Illinois)
Natalia Chepiga (University of Delft, The Netherlands)
Jens Eisert (Free University, Berlin, Germany)
Gurtej Kanwar (University of Bern, Switzerland)
Naoki Kawashima (University of Tokyo, Japan)
Michael J. Lindsey (UC Berkeley, California)
Zi Yang Meng (University of Hong Kong, China)
Rubem Mondaini (Computational Science Research Center, Beijing, China)
Miguel Morales (LLNL, Livermore, California)
Toshiro Sato (Würzburg University, Germany)
Norbert Schuch (Vienna University, Austria)
Erhard Seiler (MPI Physik, Munich, Germany)
Denes Sexty (University of Graz, Austria)
Maksim Ulybyshev (Würzburg University, Germany)
Frank Verstraete (University of Ghent, Belgium)
Congjun Wu (Westlake University, Hangzhou, China)
Hong Yao (Tsinghua University, Beijing, China)
Shiwei Zhang (Flatiron Institute, New York)
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Venue and accommodation

The conference will be held at the beautiful village of Peyresq in the lower French Alps. The entire village is the conference venue.

Participants will be lodged on two sites. Most will be on-site in Peyresq, some will be lodged at a hotel in the neighboring town of Annot. Transportation to the conference site in Peyresq and back to the hotel will be provided by the organizers.

All meals are provided by the organizers. Those staying at Peyresq will get breakfast, lunch and dinner there, while those staying in Annot will get breakfast at the hotel and the other meals at Peyresq.

A bus will be provided by the organizers to transport all participants from Nice to Annot and Peyresq and back to Nice. The bus will leave from Nice to Peyresq on Sunday July 23 in the early afternoon. It will leave Annot back to Nice in the late morning of Sunday July 30. Please arrange your arrival and departure times accordingly. You may want to arrive on Saturday 22 July and spend a night in Nice to be picked up by the bus on Sunday. And make similar allowances for the return.
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All communications about JSF-FSP should be emailed to admin@jsf-fsp.org.
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