Örs Legeza studied physics and mathematics at the Ohio State University in Columbus Ohio and later at the Eötvös Loránd University in Budapest. After finishing his PhD at the Budapest University of Technology and Economics, he served as research fellow at the Solid State Physics and Optics (Budapest), later at the Friedrich-Alexander Universität Erlangen-Nürnberg and at the Philipps University Marburg. He was one of the PIs of the Budapest-Marburg International Research Training group for eleven years, later a visiting researcher via the Experienced Researcher Fellowship from the Alexander von Humboldt Foundation.  Legeza was guest professor at the Eidgenössische Technische Hochschule Zürich, and as a Humboldt research awardee at the Freire Universität Berlin, Technische Universität Berlin and Ludwig-Maximilians-Universität München. Since 2021 he is a Hans Fischer Senior Fellow at the Institute for Advanced Studies at he Technical University of Munich. Since 2009 he is a doctor of the Hungarian Academy of Sciences and since 2012 the head of the Strongly Correlated Systems “Lendület” research group at the Wigner Research Centre for Physics.

Prizes

Hans Fischer Senior Award and Fellowship TUM-IAS (2021),  Academy Prize of the Hungarian Academy of Sciences (2021), Humboldt Research Award of the Alexander von Humboldt Foundation (2018), Lendület Award of the Hungarian Academy of Sciences (2012),  Bolyai Plaquette Award of the Hungarian Academy of Sciences (2009).

Research Interest

Örs Legeza’s main research interests focus on the development of novel tensor network state (TNS) methods and their application to strongly correlated quantum many-body systems to simulate and study magnetic properties in solid states, exotic quantum phases, complex molecular clusters, ultracold atomic systems or nuclear structures. For the method development he combines established methods for simple networks (MPS, MERA, tensor trees) with concepts from quantum information theory and computational mathematics to push the current frontier of moderate system size to much larger and more complex systems via simulations on high performance computing infrastructures.

Selected Publications

V. Ivády, G. Barcza, G. Thiering, S. Li, H Hamdi, J-P. Vhou, Ö. Legeza, A Gali, Ab initio theory of negatively charged boron vacancy qubit in hBN, npj Computational Materials volume 6, Article number:41 (2020)

I. Shapir, A. Hamo, S. Pecker, C.P. Moca, Ö. Legeza, G. Zarand, S. Ilani, Imaging the Wigner Crystal of Electrons in One Dimension , Science Vol. 364, Issue 6443, pp. 870-875 (2019

F.M. Faulstich, A. Laestadius, Ö. Legeza, R. Schneider, S. Kvaal, Analysis of The Coupled-Cluster Method Tailored by Tensor-Network States in Quantum Chemistry , SIAM J. Numer. Anal. 57, 2579 (2019)

K. Gunst, F. Verstraete, S. Wouters, Ö. Legeza, D. Van Neck, T3NS: three-legged tree tensor network states , J. Chem. Theory Comput., J. Chem. Theory Comput. 14, 4, 2026–2033, (2018)

C. Krumnow, L. Veis, Ö. Legeza , J. Eisert, Fermionic orbital optimisation in tensor network states, Phys. Rev. Lett. 117, 210402 (2016)

L. Veis, A. Antalik, F. Neese, Ö. Legeza, J. Pittner, Coupled cluster method with single and double excitations tailored by matrix product state wave functions, Journal of Physical Chemistry Letters, 7 (20) 4072-4078 (2016)

Ö. Legeza, L. Veis, A. Poves, J. Dukelsky, Advanced density matrix renormalization group method for nuclear structure calculations PHYSICAL REVIEW C RAPID COM 92:(5) 051303. 5 p. (2015)

Sz. Szalay, M. Pfeffer, V. Murg, G. Barcza, F. Verstraete, R. Schneider, Ö. Legeza, Tensor product methods and entanglement optimization for ab initio quantum chemistry, INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY 115:(19) pp. 1342-1391. (2015)

S. Knecht, Ö. Legeza, M. Reiher, Communication: Four-component density matrix renormalization group, JOURNAL OF CHEMICAL PHYSICS 140:(4) 041101. 5 p. (2014)

Ö. Legeza and J. Sólyom, Two-site entropy and quantum phase transitions in low-dimensional models, PHYSICAL REVIEW LETTERS 96:(11) 116401. 4 p. (2006)

Ö. Legeza and J. Sólyom, Optimizing the density-matrix renormalization group method using quantum information entropy, PHYSICAL REVIEW B CONDENSED MATTER (1978-1997) 68:(19) 195116. 9 p. (2003)