EventDetails

Speaker:
Dr Alessandro Romito Lancaster University, Department: Physics

This event is part of an event series „Physics Colloquium“.

Measurements are inherently probabilistic processes with an unavoidable back action on
any quantum system This back action makes the system evolve along stochastic quantum
trajectories and generally competes with unitary dynamics, leading to localisation
phenomena like the Zeno effect In many body systems, this interplay leads to
measurement induced phase transitions ( between out of equilibrium steady states
A remarkable one is a MiPT between volume and area law entanglement scaling phases,
which is not detectable in the averaged state of knowledge of the system but only
accessing the statistical distribution of the entanglement along quantum trajectories MiPTs
are being investigated and characterised in a variety of systems In this talk, I will review
quantum measurements and their back action in their discrete and continuous framework I
will first revisit the Zeno effect along individual trajectories from continuous measurements
and identify topological properties of the trajectories in the Zeno regime I will then extend
the considerations to many body fermionic systems Focusing on Gaussian fermions, I will
discuss MiPTs from competing measurements and unitary dynamics in terms of
entanglement scaling and topological order I will finally introduce a theory of partial post
selection that allows us to characterise MiPTs of subsets of quantum trajectories from the
entire ensemble to individual (post selected) trajectories.