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

carmichael

Dr Howard Carmichael, The University of Auckland
This colloquium will be held 12 noon, 25th August, in Parnell 07-234

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 Schrödinger 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”.