«Kharkiv Quantum Seminar» in collaboration with the M.M. Bogolyubov Institute for Theoretical Physics of the NAS of Ukraine and the Kyiv School of Economics invites you to the next lecture, which will take place on May 26, 2026, at 17:00 online.
Lecturer: Erik Aurell, KTH – Royal Institute of Technology (Stockholm, Sweden).
Lecture topic: “Random Gaussian pure and extremely high-dimensional quantum states”
Abstract: In condensed matter physics, for example in the context of the eigenstate thermalization hypothesis, as well as in black hole physics, a natural question arises: how thermalized can a pure quantum state appear? In black hole physics, this is the essence of Hawking’s information paradox and is related to the (huge) increase in black hole entropy compared to the matter from which it could have formed. One can also consider the inverse problem: assume the existence of a pure quantum state with some given partial thermal properties, for example, reduced states of individual modes, and try to estimate how thermalized (or non-thermalized) its other properties are. The speaker will discuss these issues within the framework of Gaussian pure states and typical properties of ensembles of random states.
In his talk, Professor Aurell will show that there exists a natural class of bounded random symplectic transformations that produce the desired marginal states and for which some multipartite properties can be estimated, namely intermodal correlations and entanglement of small subsystems. Applied to black holes, such states are as thermal as possible. The significantly more interesting case is the entanglement of sufficiently large subsystems (say, those covering about half of the modes); this remains an open problem, and the speaker will describe the corresponding consistency problem that is still unsolved.
The talk is based on joint work with Mario Kieburg, Lucas Hackl, published in Quantum Science and Technology 10, 045068 (2025), as well as on previous works with Pavel Gorodetsky and other co-authors.
About the lecturer: Erik Aurell is a professor of theoretical biological physics at KTH – Royal Institute of Technology (Stockholm), where he has worked since 2003 in the Department of Computational Science and Technology.
His scientific interests include statistical physics, open quantum systems, quantum thermodynamics, quantum black holes, computational biology, and statistical inference methods in complex systems. Erik Aurell earned his PhD at the University of Gothenburg in 1989, after which he held postdoctoral positions at the Observatory of Nice and at KTH. In 1995, he became an associate professor of mathematical physics at Stockholm University. Before moving to KTH as a professor, he worked as a researcher at the Swedish Research Council, a lecturer at Stockholm University, and a senior researcher at the Swedish Institute of Computer Science.
Professor Aurell is an honorary doctor of the M.M. Bogolyubov Institute for Theoretical Physics (2025) and an external advisor to the Department of Mathematics at the Kyiv School of Economics (KSE).
Event organizers: B.I. Verkin Institute for Low Temperature Physics and Engineering of the NAS of Ukraine (Doctor of Physical and Mathematical Sciences Serhii Shevchenko) and the National Science Center “Kharkiv Institute of Physics and Technology” (Corresponding Member of the NAS of Ukraine Andrii Sotnikov).
Conference ID: 84858248436
Conference code: 929397