Postdoctoral Researcher

Offer Description

The project is devoted to dark matter (DM). In many popular models, DM appears as a weakly interacting massive particle (WIMP), whose presence should give rise to characteristic experimental signals. The absence of such signals indicates the need to consider less conventional scenarios. In particular, DM may interact very feebly with Standard Model (SM) particles or have its mass significantly above the electroweak scale, remaining beyond the reach of conventional experimental methods. On the one hand, such scenarios often predict a dependence of the DM relic abundance on the reheating dynamics, in particular on the reheating temperature, TR. On the other hand, there is a relation between CMB observables and TR (for a given model of inflation).

The aim of the project is to develop theoretical and phenomenological methods for investigating such DM scenarios using observations of the Cosmic Microwave Background (CMB). This approach complements conventional search methods and enables tests of DM models that may remain beyond their reach.

The project builds on a recently developed framework that uses CMB data both to test models of cosmological inflation and to investigate scenarios beyond the SM that depend on TR. The planned research includes further development of this framework and its application to specific TR-sensitive DM models, such as Higgs portal models or supersymmetric models.

In our previous work, we demonstrated that constraints on TR derived from CMB observations enable tests of otherwise elusive freeze-in scenarios. These results were obtained within a standard one-parameter effective description of perturbative reheating, in which the inflaton decay width is the only free parameter, while the constant equation-of-state parameter is fixed by the dynamics of the oscillating inflaton.

The research tasks of the postdoctoral researcher will include:

1. Applying the CMB-based approach to test the TR-sensitive freeze-in mechanism in axion-portal scenarios, in which the axion acts as a mediator connecting the SM to a hidden DM sector.
2. Extending the developed framework to TR-sensitive freeze-out scenarios; applying it to concrete models such as those outlined above.
3. Investigating the impact of the non-perturbative phase of inflaton decay (in alpha-attractor models) on the possibility of testing DM models using CMB observations, employing semi-analytical methods as well as numerical evolution of the inflaton field using lattice simulations.
4. Determining the significance of non-instantaneous thermalisation of inflaton decay products (which affects both DM production and the TR–CMB link) for CMB tests of TR-sensitive DM models.
5. codes are well documented and overseeing their use and further development by a PhD student.

Duties and responsibilities:

1. Independently surveying the literature, studying in detail selected papers and accurately reproducing the analytical and numerical results.
2. Developing, testing and maintaining analytical and numerical codes for calculating dark-matter cross sections, solving Boltzmann equations and performing parameter scans, ensuring that these
3. Contributing to the preparation of manuscripts.
4. Participating in regular group meetings and reporting on the progress of the assigned research tasks.
5. Disseminating the project results by preparing and giving talks at international conferences and local seminars held at Polish institutions.

Where to apply

E-mail: pkozow@fuw.edu.pl

Requirements

Research Field: Physics

Education Level: PhD or equivalent

Skills/Qualifications

The competition is open to individuals who meet the requirements specified in Article 113 of the Law on Higher Education and Science of 20 July 2018 (Journal of Laws of 2024, item 1571, as amended) and who meet the following requirements:

1. Ph.D. in Physics.
2. Fulfilled formal requirements regarding the date of obtaining the doctoral degree in accordance with the regulations of the National Science Centre https://ncn.gov.pl/sites/default/files/pliki/uchwaly-rady/2025/uchwala72_2025-zal1.pdf. Persons without a doctoral degree may apply, provided they plan their defence no later than the date of signing the employment contract.
3. Proven experience in writing scientific publications.

In the case of a person who does not yet have a doctoral degree, a certificate of the planned date of defence.

Specific Requirements

1. Ph.D. in Physics recognised in Poland (https://kwalifikator.nawa.gov.pl/).
2. Very good knowledge of the Standard Model and of the Standard Cosmological Model.
3. Ongoing research activity at the interface of particle physics and cosmology, documented by recent publications, preprints and conference contributions.
4. Experience in carrying out computational research tasks independently and in writing texts for publications.
5. Skills in writing and using computational codes, experience in programming.
6. Experience of working in an international research environment.
7. Experience in numerical lattice simulations.

Languages: ENGLISH

Level: Good

Research Field: Physics

Years of Research Experience: 4 - 10

Additional Information

Benefits

• supporting employees with disabilities
• flexible working hours
• funding for language learning
• co-financing of training and courses
• pension plan
• savings and investment fund
• preferential loans
• additional social benefits
• leisure-time funding
• subsidizing children's vacations
• "13th" salary
• healthcare package

Eligibility criteria

1. Compatibility of the candidate's scientific profile with the advertisement (40/100 points).
2. Number, scientific level and thematic compatibility of the candidate's scientific publications and presentations (40/100 points).
3. Assessment on the doctoral diploma (10/100 points).

Internships and participation in research projects (10/100 points).

Selection process

1. Competition committee begins working no later than 14 days after the deadline for submission of documents.
2. Formal evaluation of submitted applications.
3. Call to provide additional or missing documents if necessary.
4. Selection of candidates for the interview stage (minimum score: 75/100 points).
5. Interviews with candidates who meet the formal requirements and have scored at least 75/100 points.
6. The chair of the competition committee announces the results and informs the candidates. This information will include a justification referencing the candidates' strengths and weaknesses.

NOTE: Applications must include the reference number in the email subject line and consent to the processing of personal data in the email body. Applications that do not meet these requirements will not be considered.

Additional comments

Prospects for professional development

1. Supervision in building a scientific profile through the publication in high-impact scientific journals.
2. Assistance in writing grant applications in domestic (NCN) and foreign (MSCA, Newton) research projects.
3. Gaining experience in mentoring a PhD student.
4. The opportunity to present the project results at international conferences.
5. Establishing collaborations with leading Polish research institutions.

Work Location(s)

Number of offers available: 1

Company/Institute: Faculty of Physics and Astronomy/ Adam Mickiewicz University Poznan

Country: Poland

City: Poznan

Contact

State/Province: Wielkopolska

City: Poznań

Website: http://www.amu.edu.pl

Street: Wieniawskiego 1

Postal Code: 61-712

E-Mail: klinke@amu.edu.pl