High Energy Physics Seminars

In quantum many-body systems, measurement tends to kill quantum entanglement and correlations between different degrees of freedom. Nonetheless, recent developments have explored how measurement can be used to engineer new non-equilibrium phases of matter, but mostly in the context of quantum entanglement in random quantum circuits. In this talk, I will first take a different perspective and first examine how a protocol of repeated, periodic measurements can be used to generate chiral transport in a system of free fermions [1], mimicking the anomalous Floquet topological insulators [2]. We will then examine the effects of different types of realistic disorder, namely site blockade, lattice distortions, and random onsite potential on this measurement induced chiral transport. Most notably, one observes a percolation phase transition in the flow of measurement induced chirality with percolation threshold matching previous result on the percolation cluster in a Lieb lattice [3]. Our work demonstrates how measurements can be used to engineer new states of matter, and I will point out future directions on the fundamental role of measurements in the dynamics of quantum many-body systems.

References:

[1] "Stirring by staring: Measurement induced Chirality", arXiv:2108.05906

[2] "Anomalous Edge States and the Bulk-Edge Correspondence for Periodically Driven Two-Dimensional Systems", PRX 3, 031005 (2013).

[3] "Percolation on Lieb Lattices", PRE 104, 064122 (2021).