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Quantum-atom optics research at ACQAO comprises six experimental projects directed and supported by a central theory core. For a detailed description of the research activities in the Centre, please click on the project titles in the diagram below.

Theory Core back to top

The complexity of physical systems is at the heart of many scientific problems today. A spectacular and exciting feature of modern quantum optics and ultra-cold atom experiments is the purity of the physical systems involved. The theory core of ACQAO has the challenging task of developing the fundamental theory of these systems, and proposing new experimental tests for the laboratories.

Project summaries for the ACQAO 2007 Annual Report:

arrowACQAO Theory Node at UQ
arrowANU Faculties BEC Theory Group
arrowANU IAS Nonliner Physics Theory Group

Continuous Atom Laser back to top

Presently, the low flux, and small enclosed area (in cold atom gyroscopes for example) limits the sensitivity of measurements based on atom lasers. Our goal is to push that limit by increasing flux, decreasing classical fluctuations, increasing enclosed area, and possibly squeezing the source. We aim to build a pumped atom laser where atoms are not only outcoupled from the BEC, but also replenished from a thermal cloud. Squeezing, although speculative as far as applications with cold atoms is concerned, may turn out to be very important. Present day atom laser sources have a maximum flux of a million atoms per second, leading to a minimum measureable phase shift of 1 milli-radian per root Hertz, assuming Poissonian statistics. The Heisenberg limit, for such a beam, is three orders of magnitude more sensitive. Although this degree of sqeezing has never been observed from an optical source, it may be that the strong non-linearities, that are a result of atomic interactions, allow much greater sqeeezing in a matter wave beam. Squeezing may be a viable route to significantly improved sensitivity in atom laser based measurements.

Project summaries for the ACQAO 2006 Annual Report:

arrowANU Faculties BEC Group

Coherence of a BEC on an atom chipback to top

Atom chips, or microfabricated atom optical elements on a substrate, provide an excellent platform for the coherent manipulation of matter waves and in particular for the production and quantum control of Bose-Einstein Condensates (BECs). The aims of our project involve studies of a rubidium BEC on a hybrid-technology magnetic film-wire atom chip including coherent effects and the role of decoherence in single-atom and BEC-based atom interferometry. We will examine the interaction of a quantum degenerate gas with a thermally hot environment and investigate the significance of phase in BECs. Microscopic integrated atomic circuits will lead to the construction of on-chip atom lasers and interferometers that have great potential for applications in fundamental science and for the development of miniaturised gyroscopes and gravity sensors.

Project summary for the ACQAO 2006 Annual Report:

arrowSUT Centre for Atom Optics and Ultrafast Spectroscopy

Metastable Helium BEC back to top

The main goal of our research is to study the evolution of relative phase between two Bose Einstein condensates (BEC). In particular, we would like to answer some fundamental questions about the phase of a BEC. Do two well separated BECs have an intrinsic relative phase? Or does the act of measuring atoms released from the condensates impose a relative phase on them? At what stage in the measurement of the phase is the interference pattern established? To answer these questions our group aims to build a double well metastable helium BEC.


Project summary for the ACQAO 2006 Annual Report:

arrowANU He* BEC Experimental Group

Molecular BEC back to top

The objective of this project is to produce a molecular Bose Einstein condensate (MBEC) via the association of ultracold atoms. In collaboration with the ACQAO theory group at the University of Queensland, we propose to use the MBEC to study the dissociation of the quantum degenerate molecules into correlated (entangled) atom pairs, and to investigate the coherent interaction between the MBEC and a quantum degenerate atomic gas and dynamical processes such as Bose enhanced molecule formation.



Project summary for the ACQAO 2006 Annual Report:

arrowSUT Centre for Atom Optics and Ultrafast Spectroscopy

Atom-Light Entanglement back to top

The coherent and reversible storage of the quantum state of a light field is an important issue for the realization of many protocols in quantum information processing. In the past four years much work has been done on this topic utilizing the phenomenon of electromagnetically induced transparency (EIT). Our interest is in extending previous work on this topic by quantifying the fidelity of such a scheme when one tries to store two specific forms of quantum information: squeezing and entanglement, and taking full account the effects of the ground state dephasing rate and the quantum noise contribution of the atoms.

 


Project summary for the ACQAO 2006 Annual Report:

arrowANU Quantum Optics Experimental Group

Quantum Imaging back to top

Spatial measurements, such as the detection of the displacement and tilt of a beam of light, suffer from limitations in the accuracy similar to those encountered in temporal signals. The signal to noise ratio is limited by the quantum noise. However, it is possible to surpass this limit using spatial squeezing, in analogy to conventional temporal squeezing, and this is the goal for this project.







Project summary for the ACQAO 2006 Annual Report:

arrowANU Quantum Imaging Group

 
 

Last updated: May 24, 2008
Designed and maintained by: Paul Schwenn (schwennphysics.uq.edu.au)
Contents coordinator and supervisor: Karen Kheruntsyan (kheruntsphysics.uq.edu.au)