Condensed Matter Seminar: Introduction to the quantum first detection problem

Abstract:

We consider quantum dynamics on a graph, with repeated strong measurements performed locally at a xed time interval . For example a particle starting on node x and measurements performed on another node x0. From the basic postulates of quantum mechanics the string of measurements yields a sequence no,no,no, and nally in the n-th attempt a yes, i.e. the particle is detected. Statistics of the rst detection time n are investigated, and compared with the corresponding classical rst passage problem. Dark states, Zeno physics, a quantum renewal equation, winding number for the rst return problem (work of A. Grunbaum et al.), total detection probability, detection time operators and time wave functions are discussed.

References:

[1] H. Friedman, D. Kessler, and E. Barkai Quantum walks: the rst detected passage time problem Phys. Rev. E. 95, 032141 (2017). Editor's suggestion.

[2] F. Thiel, E. Barkai, and D. A. Kessler First detected arrival of a quantum walker on an in nite line Phys. Rev. Lett. 120, 040502 (2018).

Event Organizer: Prof. Sasha Gerber