Learning Feedback Control Strategies for Quantum Metrology

Optimal adaptive control for quantum metrology with time-dependent Hamiltonians

Quantum metrology has been studied for a wide range of systems with time-independent Hamiltonians. For systems with time-dependent Hamiltonians, however, due to the complexity of dynamics, little has been known about quantum metrology. Here we investigate quantum metrology with time-dependent Hamiltonians to bridge this gap. We obtain the optimal quantum Fisher information for parameters in tim...

Feedback Strategies for Interactive Learning Tasks

Modern information technologies increase the range of feedback strategies that can be implemented in computer based learning environments; however, the design and implementation of feedback strategies are very complex tasks that are often based more on intuition than on psychologically sound design principles. The purpose of this chapter is to present theoretically and empirically based guideli...

Quantum error correction for metrology.

We propose and analyze a new approach based on quantum error correction (QEC) to improve quantum metrology in the presence of noise. We identify the conditions under which QEC allows one to improve the signal-to-noise ratio in quantum-limited measurements, and we demonstrate that it enables, in certain situations, Heisenberg-limited sensitivity. We discuss specific applications to nanoscale sen...

Learning Strategies for Saccade Control

Optimal Quantum Feedback Control for Canonical Observables

We show that the stochastic Schrödinger equation for the filtered state of a system, with linear free dynamics, undergoing continual nondemolition measurement or either position or momentum, or both together, can be solved explicitly within a class of Gaussian states which we call extended coherent states. The asymptotic limit yields a class of relaxed states which we describe explicitly. Bellm...