Measurement induced quantum walks

Abstract

We investigate a tight binding quantum walk on a graph. Repeated stroboscopic measurements of the position of the particle yield a measured "trajectory", and a combination of classical and quantum mechanical properties for the walk are observed. We explore the effects of the measurements on the spreading of the packet on a one dimensional line, showing that except for the Zeno limit, the system converges to Gaussian statistics similarly to a classical random walk. A large deviation analysis and an Edgeworth expansion yield quantum corrections to this normal behavior. We then explore the first passage time to a target state using a generating function method, yielding properties like the quantization of the mean first return time. In particular, we study the effects of certain sampling rates which cause remarkable change in the behavior in the system, like divergence of the mean detection time in finite systems and a decomposition of the phase space into mutually exclusive regions, an effect that mimics ergodicity breaking, whose origin here is the destructive interference in quantum mechanics. For a quantum walk on a line we show that in our system the first detection probability decays classically like $(\text{time}{)}^{-3/2}$, this is dramatically different compared to local measurements which yield a decay rate of $(\text{time}{)}^{-3}$, indicating that the exponents of the first passage time depends on the type of measurements used.

22 pages, 18 figures

References in corpus (8)

• Realization of quantum walks with negligible decoherence in waveguide lattices
• Decoherence in quantum walks - a review
• Detection of a quantum particle on a lattice under repeated projective measurements
• Quantum walks on quotient graphs
• First detected arrival of a quantum walker on an infinite line
• Quantumness in decoherent quantum walk using measurement-induced disturbance
• Measurements in the Lévy quantum walk
• Uncertainty relation between detection probability and energy fluctuations

Cited by in corpus (13)

• Topological Speed Limit
• Measurements on an Anderson Chain
• Measurement induced quantum walks on an IBM Quantum Computer
• Restart uncertainty relation for monitored quantum dynamics
• Resonances of recurrence time of monitored quantum walks
• Causality, localization, and universality of monitored quantum walks with long-range hopping
• Discrete-time Semiclassical Szegedy Quantum Walks
• Measurement Induced Chirality II: Diffusion and Disorder
• Observation of partial and infinite-temperature thermalization induced by repeated measurements on a quantum hardware
• Performance advantage of protective quantum measurements
• Accelerated first detection in discrete-time quantum walks using sharp restarts
• On Hitting Times for General Quantum Markov Processes
• Monte Carlo particle transport on quantum computers