I am a physics PhD working as a postdoc in the Laboratory for Quantum Optics and Quantum Foundations at the Faculty of Mathematics and Physics, University of Ljubljana. There, we work on sources of entangled photons and quantum communication protocols. Our current main project is SiQUID, aiming to build the first quantum network in Slovenia.

I also work as a research associate at the Department of Theoretical Physics, Jožef Stefan Institute, studying nonequilibrium interacting topological insulators with doc. Tomaž Rejec and doc. Jernej Mravlje. I’ve published works with prof. Anton Ramšak on nonadiabatic quantum computing and decoherence.

Curriculum vitae

Thesis

Nonequilibrium dynamics of topological insulators
L. Ulčakar
Advisors: doc. Tomaž Rejec, doc. Jernej Mravlje
PhD thesis, University of Ljubljana (2020)

Stability of magic ratios of conductance through small graphene-like structures
L. Ulčakar
Advisors: prof. Anton Ramšak, doc. Tomaž Rejec
Masters thesis, University of Ljubljana (2016)

Publications

• Quantum anomalous Hall domains in a quenched topological Mott insulator
  L. Ulčakar, G. Lemut, T. Rejec, J. Mravlje
  Phys. Rev. B 111, 195141 (2025), arXiv:2502.05035 (2025)
• Designing a compact cavity-enhanced source of entangled photons
  Ž. Pušavec, L. Ulčakar, R. Kaltenbaek
  Phys. Rev. A 111, 043707 (2025), arXiv:2408.16666 (2024)
• Spin Hall conductivity in insulators with non-conserved spin
  D. Monaco, L. Ulčakar
  Phys. Rev. B 102, 125138 (2020), arXiv:2006.12071 (2020)
• Kibble-Zurek behavior in disordered Chern insulators
  L. Ulčakar, J. Mravlje, T. Rejec
  Phys. Rev. Lett. 125, 216601 (2020), arXiv:2003.08439 (2020)
• Thermal effects on a nonadiabatic spin-flip protocol of spin-orbit qubits
  B. Donvil, L. Ulčakar, T. Rejec, A. Ramšak
  Phys. Rev. B 101, 205427 (2020), arXiv:2002.05548 (2020)
• Slow quenches in Chern insulator ribbons
  L. Ulčakar, J. Mravlje, T. Rejec
  Phys. Rev. B 100, 125110 (2019), arXiv:1905.12691 (2019)
• On the resilience of magic number theory for conductance ratios of aromatic molecules
  L. Ulčakar, T. Rejec, J. Kokalj, S. Sangtarash, H. Sadeghi, A. Ramšak, J. H. Jefferson, C. J. Lambert
  Scientific Reports 9, 3478 (2019)
• Slow quenches in two-dimensional time-reversal symmetric Z2 topological insulators
  L. Ulčakar, J. Mravlje, A. Ramšak, T. Rejec
  Phys. Rev. B 97, 195127 (2018), arXiv:1802.05572 (2018)
• Exact spin-orbit qubit manipulation
  A. Ramšak, T. Čadež, A. Kregar, L. Ulčakar
  Eur. Phys. J. Special Topics 227, 353–363 (2018), arXiv:1711.02134 (2017)
• Effects of noise on fidelity in spin-orbit qubit transformations
  L. Ulčakar, A. Ramšak
  Int. J. Mod. Phys. B 32, 1840028 (2018), arXiv:1711.01459 (2017)
• Exact analysis of gate noise effects on non-adiabatic transformations of spin-orbit qubits
  L. Ulčakar, A. Ramšak
  New J. Phys. 19, 093015 (2017), arXiv:1705.01716
• Linear conductances of gated graphene structures with selected connectivity
  L. Ulčakar, T. Rejec, A. Ramšak
  Acta Chim. Slov. 63(3), 2016