Marko Žnidarič (University of Ljubljana)
Hybrid seminar: onsite + zoom.
Meeting ID: 960 0269 7257
Describing full unitary dynamics of a many-body system is difficult and also unpractical. Focusing on a coarse-grained dynamics, or few select smooth observables, often results in a more compact non-unitary evolution. Studying bipartite entanglement dynamics in random circuits one can derive a Markovian transfer matrix description that harbors rather intriguing many-body non-Hermitian physics. The speed of generating entanglement is not given by the 2nd largest eigenvalue of the transfer matrix, but rather by a phantom eigenvalue that is not in the spectrum of any finite transfer matrix. Resolution of this seeming paradox will involve a spectrum that is completely discontinuous in the thermodynamic limit. When dealing with finite non-Hermitian matrices it can turn out that being exact is actually wrong, while being slightly wrong is correct.