Dóra, Balázs


F III. GF 5.
dora.balazs (at) ttk.bme.hu
+36 1 463 3829


Szilárd Leó Colloquium

Many-body theory I.

Supervised students: Péter Boross (MSc, 2012), Izabella Lovas (BSc, 2012), Balázs Gulácsi (BSc, 2013, Msc 2015, currently PhD student), Szabolcs Vajna (PhD, 2017), Zoltán Okvátovity (Bsc, 2016, currently Msc student), Dávid Pataki (currently MSc student) 

Quantum mechanics



Recent advances in cold atomic systems and condensed matter have made the realization of several exotic phenomena possible, such as coherent quantum many-body dynamics and various topological states of matter. These are fundamentally compelling and once understood, potentially lead to applications in the field of spintronics, quantum technologies, quantum information theory and (topological) quantum computation. The following open issues motivate my research:


1. There is nothing more quantum mechanical than entanglement, i.e. the presence of non-local correlations in quantum systems. While much is known about entanglement characteristics in real space, momentum space entanglement remains largely unexplored. We study momentum space or in general, Fock space entanglement in a variety of setting, including higher dimensional, strongly correlated and topological systems, in and out of equilibrium.


2. The topological properties of matter can successfully be altered by applying time periodic perturbations. We  focus on the effect of quantized light – matter interactions in a variety of systems, including graphene, topological insulators and superconductors, spin liquids etc. We investigate the possibility of inducing topological states of matter by quantized electromagnetic fields, and its competition with other phases and instabilities.


3. The quantum butterfly effect, i.e. sensitivity of a system to small perturbations, and information scrambling occurs in chaotic models. We disentangle chaotic from regular behaviour in a variety of systems by focusing out-of-time-ordered correlators, analyse the role of topology, correlations and quantum quenches.


The expected results will promote the fundamental understanding of equilibrium and non-equilibrium quantum many-body systems, flavoured by topology.

Selected publications

Our first work on non-hermitian systems was publishedin Nature Communications: the Kibble-Zurek mechanism at exceptional points.


Everything you wanted to know about graphene's superconductivity, but did not dare to ask: viewpoint in Physics by APS


Back to basics: my 20th PRL is on the center of mass coordinate --- in a quantum liquid.


Our paper on the spin relaxation in strong spin-orbit coupled materials has been selected as the most important scientific publication of BME in 2017.


Have you ever wondered about the order parameter for a dynamical quantum phase transition? Check the OTOC!


Our recent paper on the entanglement properties of Kitaev's spin liquid has been selected as Editors' suggestion in Phys. Rev. B.


Our new paper on the out-of-time-ordered correlators has been published recently in Physical Review Letters.


20 Phys. Rev. Lett, 1900+ citations from MTMT, h-index 23, DSc (MTA doktora), professor

PI of K119442 OTKA grant, head of the Topology and Correlation MTA-BME Lendület Research Group

Co-organiser of the conference ”Interactions and Topology in Dirac Systems” in 2016 at the Abdus Salam International Center for Theoretical Physics, Trieste, Italy.


My own list of publication (including arxiv citations)


Articles and citations as Google Scholar sees them


Invited presentations in scientific conferences


1. 2005 Workshop on Correlated Thermoelectric Materials, Hvar, Croatia, “Nernst effect in unconventional density waves”

2. 2008 International Winterschool on Electronic Properties of Novel Materials, Kirchberg, Austria, “Spin gap and Luttinger Liquid description of the NMR relaxation in carbon nanotubes"

3. 2008 IRTG Workshop: A New Carbon Age, Ráckeve, Hungary, "Strong correlation effects in carbon nanotubes"

4. 2009 International Winterschool on Electronic Properties of Novel Materials, Kirchberg, Austria, "Electron spin resonance signal of Luttiner liquids and single wall carbon nanotubes"

5. 2009 Symposium on "Frontiers in low-temperature physics", MPIPKS, Dresden, Germany, "Rabi oscillations in Landau quantized graphene"

6. 2009 CFP Workshop on Graphene, Porto, Portugal, “Nonlinear electric transport in graphene”

7. 2010 International Winterschool on Electronic Properties of Novel Materials, Kirchberg, Austria , “Unusual hyperfine interaction of Dirac electrons and NMR spectroscopy in graphene”

8. 2010 International Workshop for Electronic Materials and Superconductivity, Israel (could not attend)

9. 2011 Workshop on QFT aspects of Condensed Matter systems, Rome, Italy (could not attend) 10.2012 Topology and correlations, MPIPKS, Dresden, Germany, “Optically engineering the topological properties of a spin Hall insulator”

11.2013 Flat Bands: Design, Topology, and Correlations, MPIPKS, Dresden, Germany (could not attend)

12.2013 International Winterschool on Electronic Properties of Novel Materials, Kirchberg, Austria , “Floquet topological insulators”

13.2013 Triannual Meeting of the Roland Eotvos Physical Society, Debrecen, Hungary, “Floquet topological isulator”

14.2014 Topological Matter out of Equilibrium, MPIPKS, Dresden, Germany

15.2014 2nd Summer School on Exact and Numerical Models for Low-Dimensional Quantum Structures, Turunc, Turkey (could not attend)

16.2014 Topological and Dirac matter: from modeling to imaging, Bordeaux, France, “Optically engineering the topological properties of a spin Hall insulator”

17.2015 Many-body Dynamics out of Equilibrium, MPIPKS, Dresden, Germany (could not attend)

18.2015 International Winterschool on Electronic Properties of Novel Materials, Kirchberg, Austria, “Nematic, topological and Berry phases when a flat and a parabolic band touch”

19.2015 The 19th Symposium on Condensed Matter Physics, Belgrade, Serbia

20.2016 International Winterschool on Electronic Properties of Novel Materials, Kirchberg, Austria, “From Floquet to Dicke: spin Hall insulator in quantum light”

21.2016 Quantum non-equilibrium phenomena, Natal, Brazil


2010 Orvay Colloquium, Eötvös University, “Dirac elektronok nemegyensúlyi transzportja grafénban”

2013 Bolyai-day, MTA, Budapest, “A grafén csodálatos világa: Dirac elektronok nem- egyensúlyi dinamikája

2014 Bilkent Colloquia, Bilkent University, Ankara, Turkey, “How to Engineer the Band Structure of a (Topological) Insulator?”

2015 Orvay Colloquium, Eötvös University, “Floquet topological insulators