Postdoctoral Researcher in Quantum Complexity and Matrix Theory

Fysikum is one of the larger institutions within the Faculty of Science, with a broad fundamental research activity, both experimental and theoretical.

The department has about 250 employees, including 95 PhD students, and has an international character. Fysikum is part of the AlbaNova University Center, which is a strong research center that, in addition to Fysikum, also houses the Department of Astronomy, the physics departments at KTH, and the Nordic Institute for Theoretical Physics, Nordita. More information about us can be found at: https://www.su.se/enheter/fysikum (https://www.su.se/enheter/fysikum)

Stockholm University is part of the Stockholm Dual Career Network (SDCN), which supports partners of international recruits with professional events, career-related advice, and by building social networks in their new hometown. You can read more here: https://www.staforum.se/sdcn/ (https://www.staforum.se/sdcn/)

Project Description

Complexity is a fundamental concept that quantifies the difficulty of performing a certain task, given a specific set of allowed, simple operations and a procedure to achieve it. As such, it is an important part of many areas from mathematics to computer science. Surprisingly, physics still lacks an exact definition of quantum complexity, and this is one of the most pressing problems at the forefront of quantum theory and quantum gravity.

The position is part of the ERC Consolidator project "Quantum Complexity from Quantum Field Theories to Quantum Gravity" (Project Leader: Pawel Caputa) aimed at bridging this gap.

The goal of the project is to develop universal measures of quantum complexity for many-body systems, quantum field theories, and quantum gravity. The project's milestones include: synthesizing and developing physical measures of complexity, formulating them in exact holographic models, and applying them to shed new light on the physics behind black hole horizons and spacetime singularities.

Matrix theory is an important approach to non-perturbative string theory where quantum gravity emerges from relatively simpler quantum systems of matrices. Such matrix quantum mechanical systems arise from certain decoupling limits in string theory that zoom in on states protected by supersymmetry. The same decoupling limits also underlie the AdS/CFT correspondence.

The position within the Olle Engkvist Foundation project “Emergent Universe Matrix Quantum Mechanics” (PI: Ziqi Yan) aims to deepen our understanding of matrix theory and broaden the landscape of decoupling limits in string theory using recently developed non-Lorentzian geometric techniques. Mapping such decoupling limits and their quantum properties will not only deepen our understanding of quantum gravity in sub-string regimes but may also lead to holographic constructions of gravity on realistic backgrounds.

The project's milestones include: (1) classification of decoupling limits focusing on orthogonal branes; (2) generalizations of decoupling limits to giant gravitons and field-theoretic formulation of spin matrix theories; (3) constructions of holographic dualities with de Sitter, flat space, and non-Lorentzian bulk geometries.

The postdoctoral position within the VR project "Emergent spacetime from non-relativistic holography" (PI: Niels Obers) aims to develop a new theoretical understanding of how spacetime and gravity can emerge from quantum mechanical degrees of freedom in non-relativistic holographic frameworks. The project focuses on establishing and exploiting controllable limits of string theory and holography—particularly non-Lorentzian (e.g., Galilean/Newton-Cartesian and related) geometries and dual field theories—to map the underlying duality structure and illuminate non-perturbative phenomena with connections to black hole physics and quantum field theory.

Job Responsibilities

The job responsibilities primarily involve research conducted in close collaboration with the project leader, PhD students, and other group members. The responsibilities will also include assisting in organizing group activities.

Eligibility Requirements

To be eligible for the position of postdoctoral researcher, a completed PhD or foreign degree assessed to be equivalent to a relevant doctoral degree is required. The degree must be completed by the time the employment decision is made.

Assessment Criteria

It is advantageous if the PhD or equivalent has been completed no more than three years before the application deadline. If there are special reasons, an earlier degree may also be considered advantageous. Special reasons include leave due to illness, parental leave, trust assignments within trade unions, service in the total defense, or other similar circumstances, as well as clinical service or relevant service/assignments for the subject area.

In the recruitment process, particular emphasis will be placed on researchers with experience in AdS/CFT correspondence, quantum field theory, quantum complexity, and quantum information.

About the Position

The position is full-time and is for 2 years with the possibility of extension if there are special reasons. Start date is 2026-09-01 or by agreement.

We Offer

With us, you will experience the dynamics of the interplay between higher education and research that makes Stockholm University an exciting and creative environment. You will work in an international setting and receive favorable conditions. The university is located in the National City Park with good connections to the city.

Stockholm University is committed to being a workplace free from discrimination and providing equal rights and opportunities for all.

Contact

Inquiries about the position can be made to Pawel Caputa, phone 08-5537 8018, [email protected] (mailto:[email protected]).

Application

You apply for the position via Stockholm University's recruitment system. Attach a personal letter and CV as well as the documents requested in the application form. As an applicant, you are responsible for ensuring that the application is complete and that it reaches the university by the application deadline.

Instructions for applicants can be found on the website: https://www.su.se/om-universitetet/jobba-på-su/att-söka-en-anställning (https://www.su.se/om-universitetet/jobba-p%C3%A5-su/att-s%C3%B6ka-en-anst%C3%A4llning).

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