Sign '18 - General Information



The "sign problem" (or oftentimes the complex phase problem) is a serious difficulty in Monte Carlo simulations of QCD at finite baryon densities or with a topological term. But also in quantum many body problems in nuclear and condensed matter physics, sign problems are present and can be severe. Examples can be found in various models ranging from asymmetric nuclear matter to frustrated quantum systems. The difficulty at the heart of the sign problem is that contributions to the partition function are highly oscillatory, resulting in large cancellations and thus lead to a signal to noise problem. A generic solution to the sign problem may not exist, however, the severity of the sign problem depends on the degrees of freedom used to represent the partition function. Reformulating the original model often goes along with algorithmic developments. Most of the time those simulations nevertheless need to be carried out on supercomputers. For many specific models, sign problems have been successfully solved or circumvented. This international workshop intends to bring together physicists from condensed matter and field theory with an interest in computational methods to discuss prospects of solving sign problems.



The workshop will start on

Monday, September 10, 9am

and end on

Friday, September 14, 3pm.

The workshop fee will be 50 Euro to be paid cash on-site and will cover coffee breaks and a workshop dinner.

We are happy to give a limited number of stipends to PhD students which will waive the workshop fee and will cover the hotel costs during the workshop. Interested students should send their application and one letter of reference to



Scientific Topics

The workshop will cover a broad range of topics including:

  • QCD and Related Theories

  • Algorithmic Developments