VIHREN Postdoctoral Fellowship

Job type: Postdoc fellowship, full-time
Start date: flexible
Job duration: two years with an option to extend for a third year
Location: Faculty of Physics, Sofia University, 5 James Bourchier Blvd, 1164 Sofia, Bulgaria (EU)
Supervisor: Marin Bukov, PhD
Requirement: successful applicants must hold a PhD degree at the start date of the job

Applications are now open for a VIHREN postdoc fellowship (see also job ad for PhD positions).

We are currently looking for a highly motivated and skilled postdoc/experienced researcher to join a new research group at Sofia University. The group is funded by a VIHREN research frontier grant from the Bulgarian National Science Foundation, and a Marie Sklodowska-Curie actions grant from the European Commission’s Research Executive Agency. The group maintains an active network of international collaborations with leading groups in the field [Berkeley, Boston, Brussels, Harvard, Munich, etc.].

We are interested in a broad range of topics revolving around the field of quantum many-body systems [non-equilibrium quantum dynamics, condensed matter theory (phase transitions, critical phenomena), AMO physics, and statistical physics], developing techniques and ideas from Deep Learning for quantum systems; we are looking for applicants of diverse scientific background. Our research results are applicable in experimental platforms, e.g., ultracold atoms, trapped ions, and superconducting circuits. Concrete examples of past projects can be found on

Applicants are expected to (i) have research experience in one or more of the above-listed fields, and (ii) be prepared to expand their knowledge through active, full-time research. The postdoctoral fellow will be encouraged to become an independent researcher through interactions with the group, following an individual career development plan. The working language in the group is English. By the end of their fellowship, VIHREN postdoc fellows will develop a broad research expertise useful to pursue a career in both academia and industry.

VIHREN postdoc fellowship benefits:

  • very competitive salary
  • laptop
  • travel budget for participation in international conferences, workshops, and schools
  • opportunities for collaboration with an international network of leading scientists in the field, and local experts

The group has active international collaborations with leading groups in the field [Berkeley, Boston, Brussels, Harvard, Munich, etc.], which the successful applicant will be able to participate in. Additionally, there are opportunities for strong local collaborations at the Faculty of Physics [e.g., the Quantum Optics and Quantum Information Group], and multiple institutes of the Bulgarian Academy of Sciences (BAS). VIHREN postdoc fellows will also have a travel budget to participate in conferences, schools, and workshops.

Although the primary focus of our research is the understanding of the behavior and phenomena of physical systems, investigating quantum many-body models away from equilibrium often requires the use of numerical simulations. Research projects in the group involve writing scientific code and performing numerical simulations. Therefore, a solid knowledge of (at least one) programing language (e.g., Python, C++, Julia, or similar) is required. Familiarity with a quantum mechanics library [e.g., QuTip, QuSpin, TeNPy, iTensor, NetKet], or at least one machine learning package [e.g., TensforFlow, PyTorch, JAX], or relevant coding experience is not required but will be considered an advantage. Familiarity with parallel programming [e.g., OpenMP, Open MPI, CUDA, etc.] will also be considered an advantage. The supervisor is one of the developers of QuSpin, and postdocs can participate in scientific software development.

The group has access to the three hpc clusters: Physon, Nestum and the hpc at the Center of Excellence in Informatics and Information and Communication Technologies, BAS. The successful postdoc applicant will be provided with a laptop as part of the VIHREN fellowship.

Scientific activities in the group will include a weekly group meeting to discuss recent progress in the field, and participation in journal clubs and seminars on topics of common interest. Group members may also be asked to help with the teaching activities the group is involved in. To build a friendly and productive work environment, VIHREN fellows – as an integral part of the group – will be cordially invited to join in non-scientific activities [Sofia lies in between Vitosha mountain and the Balkan mountains which provide many opportunities for outdoor activities, and enjoy a four-season weather].

Application Materials: interested applicants should send the following materials to Marin Bukov at mgbukov(at) Please, use the subject line “VIHREN postdoc fellowship application”:

  1. CV (including a list of publications, conference presentations and scientific talks; list any particular achievements you consider important for this job),
  2. the names and e-mail contacts of three References, who we will contact for letters of recommendation,
  3. transcript of records for your PhD studies (if available).

We strongly encourage both physics PhD holders with interest in machine learning, and computer science PhD holders with knowledge of quantum mechanics to apply for the VIHREN postdoc fellowship!

Competitive applicants will be invited for an interview. This position will remain open until filled, but we will have more openings in the following years. Long-term applicants, i.e. those who seriously consider joining the group in a few years from now as a postdoc fellow, are already invited to contact me well ahead of time via email to request more information about future projects and research directions. The position is open as part of the research project “Reinforcement Learning to Manipulate Quantum Matter away from Equilibrium”, funded by a VIHREN frontier research grant from the Bulgarian National Science Foundation.
Non-EU/EEA citizens may require a work permit for Bulgaria; we will provide the necessary assistance.

Sofia University “St. Clement of Ohrid” is the oldest research university in Bulgaria and one of the largest in south-east Europe, with about 20,000 students. Situated within walking distance from downtown Sofia in Sofia University’s Lozenets campus, the Faculty of Physics hosts research groups in various areas of modern physics, and has been enjoying the most productive research environment in Bulgaria [340 publications/yr. (Web of Science) in 2018]. The Quantum Optics and Quantum Information theory group hosts the annual workshop CAMEL (Control of quantum dynamics of Atoms, Molecules and Ensembles by Light). The Faculty of Physics shares campus with the Faculty of Mathematics & Informatics, and the Faculty of Chemistry & Pharmacy, providing opportunities for interdisciplinary collaborations. The Bulgarian capital Sofia also hosts the institutes for Solid State Physics and Informatics, and Information and Communication Technologies (ICT) at the Bulgarian Academy of Sciences, with groups interested in condensed matter, quantum optics, and ML/big data.