## Quantum Trajectories, Decoherence, and What One MIGHT Read from the Environment

University of Auckland, New Zealand

Recent experiments with superconducting qubits have dramatically changed
the landscape for addressing elementary quantum systems - both in the preparation
and measurement of quantum states. Even the reconstruction of individual quantum trajectories
is now carried out. In this talk, I first introduce the idea of a "quantum trajectory,"
where I contrast the jump trajectory of photon counting with the diffusive trajectory
applicable to superconducting qubits. I then explore two applications, one related
to the infamous Schrodinger cat and the other to the Bohr-Schrödinger discussion of
quantum jumps from 1926; both, in a modern context, illuminate the meaning of that
catchword "decoherence."