[Physstaff] Colloquium Wed 20/4/2016: "Quantum metrology with Bose Einstein Condensates" Markus Oberthaler (Heidelberg)

[Daniel Oi]

The final colloquium of the current series will be given by Prof Markus Oberthaler. As usual, tea/coffee will be served afterwards.

Title: Quantum metrology with Bose Einstein Condensates
Speaker: Markus Oberthaler, Kirchhoff Institute for Physics, University of Heidelberg
Venue: John Anderson JA3.14
Time/Date: 3pm Wednesday 20th April 2016
 
Abstract:
One aspect of metrology, the science of measurement, is the exploration of the ultimate precision limit. It is known for quite some time that the new possibilities in quantum mechanics allow the surpassing of the ultimate classical precision limit given by counting statistics. Quantum metrology is about the exploration of these new limits. The goal is the generation and characterization of useful quantum mechanical resources for going beyond the classical precision limits. Since the gain in precision is intimately connected to quantum entanglement in many particle systems these investigations are also interesting from the fundamental point of view.

In this colloquium I will discuss in detail how Bose Einstein condensates can be used to generate entangled many particle states which push atom interferometry beyond the classical limits.  I will use the system of two component atomic condensates as a model system for explaining how quantum correlations arise and how they can be used for improved estimation of a phase shift in an atom interferometer. The simplest form of useful many particle quantum states are spin squeezed states which can be classified as Gaussian states. With the experimental platform of ultracold gases even non-gaussian states can be generated. Their proper characterization involves the quantum Fisher information which will be explained in detail.