Holographic descriptions of collective modes in strongly correlated media
Licentiate thesis, 2019

Solving the puzzle of high temperature superconductivity may be one of the most desired scientific breakthroughs of our time, as access to room temperature superconductivity could revolutionize society as we know it. In this thesis, we strive to increase the theoretical understanding of such matter, by studying the phase above, in temperature, the superconducting phase - the "strange metal".

The strange metal phase is a phase characterized by the absence of a quasi-particle description. The electrons in this phase are strongly coupled, which means that conventional methods, such as perturbation theory in quantum field theory and Monte Carlo methods fall short of being able to describe their dynamics. Perhaps surprisingly, string theory provides a different method, capable of describing precisely such systems - the holographic duality.

Whereas there has been significant effort devoted to the applications of the duality since its inception in 1997, and even more so in the last decade after it was observed that it worked remarkably well for condensed matter theory, it wasn't until our project that the dynamical polarization of such strongly coupled systems where properly treated.

In this thesis, we introduce the minimal constraints required for a sensible description of a polarizing medium, and convert those to boundary conditions to the equations of motion provided by the holographic dual. These boundary conditions deviate from previous holographic studies, and we contrast the quasinormal modes previously studied with the emergent collective modes we find for some different models.

We find novel results, as well as confirm the predictions of less general models in their respective regions of validity and pave the way for more complex future models.


strongly correlated media


gauge/gravity duality


strong coupling

quasinormal modes

PJ-salen, Fysikgården 2B, Fysik Origo
Opponent: Prof. Mats Granath, Department of Physics, University of Gothenburg, Sweden


Marcus Tornsö

Chalmers, Physics, Theoretical Physics

Holographic response of electron clouds

Journal of High Energy Physics,; (2019)

Journal article

Exotic holographic dispersion

Journal of High Energy Physics,; Vol. 2019(2019)

Journal article

Holographic plasmons

Journal of High Energy Physics,; (2018)

Journal article

Gran, U, Tornsö, M, Zingg, T. Plasmons in Holographic Graphene

Applied String Theory - Holographic Methods for Strongly Coupled Systems

Swedish Research Council (VR) (2015-04368), 2016-01-01 -- 2019-12-31.

Subject Categories

Subatomic Physics

Physical Sciences

Atom and Molecular Physics and Optics

Condensed Matter Physics


Basic sciences


Chalmers University of Technology

PJ-salen, Fysikgården 2B, Fysik Origo

Opponent: Prof. Mats Granath, Department of Physics, University of Gothenburg, Sweden

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