Abstract
The problem of the detection statistics of a quantum walker has received increasing interest. We investigate the effect of employing a moving detector, using a projective measurement approach with fixed sampling time, with the detector moving right before every detection attempt. For a tight-binding quantum walk on the line, the moving detector allows one to target a specific range of group velocities of the walker, qualitatively modifying the behavior of the quantum first-detection probabilities. We map the problem to that of a stationary detector with a modified unitary evolution operator and use established methods for the solution of that problem to study the first-detection statistics for a moving detector on a finite ring and on an infinite 1D lattice. On the line, the system exhibits a dynamical phase transition at a critical value of from a state where the probability of detection decreases exponentially in time and the total detection probability is very small, to a state with power-law decay and a significantly higher total probability to detect the particle. The exponent describing the power-law decay of the detection probability at this critical is 10/3, as opposed to 3 for every larger In addition, the moving detector strongly modifies the Zeno effect. 2019 IOP Publishing Ltd.
Original language | English |
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Article number | 354001 |
Journal | Journal of Physics A: Mathematical and Theoretical |
Volume | 52 |
Issue number | 35 |
DOIs | |
State | Published - 2 Aug 2019 |
Keywords
- first passage
- quantum walk
- renewal equation
All Science Journal Classification (ASJC) codes
- Statistical and Nonlinear Physics
- General Physics and Astronomy
- Statistics and Probability
- Mathematical Physics
- Modelling and Simulation