Probing out of equilibrium properties of strongly correlated cold atoms

Lead Research Organisation: University of Birmingham
Department Name: School of Physics and Astronomy

Abstract

This proposal concerns the dynamical phenomena in cold atomic gases. Theobjective is to use these clean and controllable systems for understandingthe dynamical response of very cold interacting many body systems to a suddenchange of physical parameters driving the system out of equilibrium.The objects of this study will be bosonic and fermionic ultra-cold atoms inoptical lattices. The inhomogeneous density profile due to harmonicconfinement leads to coexistence of quantum phases and results in richdynamical response. An important case concerns atomic systems in lowdimensions. Here analytical results are for dynamics are expected by usingthe exact method of statistical physics, such as Bethe Ansatz. Finally, thesestudies will include atoms moving in disordered environment. Theunprecedented control on the distribution of disorder and atomic interactionswill shed light on the long standing problem of disordered bosons and provideconnection with condensed matter physics. Aside from the fundamental interest in studying non-equilibrium quantum manybody systems this project will provide links to current experimental studiesof cold atoms and eventually will result in possible applications in the areaof precise measurements, atomic waveguides and quantum informationprocessing.

Publications

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Chudnovskiy A (2012) Doublon Relaxation in the Bose-Hubbard Model in Physical Review Letters

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Gangardt D (2008) Correlations in an expanding gas of hard-core bosons in Physical Review A

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Gangardt DM (2009) Bloch oscillations in a one-dimensional spinor gas. in Physical review letters

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Gangardt DM (2010) Quantum decay of dark solitons. in Physical review letters

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Sykes AG (2008) Spatial nonlocal pair correlations in a repulsive 1D Bose gas. in Physical review letters

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Wadkin-Snaith D (2012) Quantum Gray Solitons in Confining Potentials in Physical Review Letters

 
Description The key finding of the grant are as follows: it was shown how a quantum gas of atoms constrained to move in one dimension arranges itself such that the particles feel presence of each other. This was done by calculating the density-density correlation functions which are a new theoretical result. These function has been calculated in equilibrium situation or after a sudden release of the trapping potential. In the latter case we have shown that for very strong interactions between the atoms the particles "remember" their initial arrangement in contrast to three dimensions where atoms equilibrate. This effect can be measured in current experiments with ultracold atoms. Another key finding is the dynamical properties of mobile impurities immersed in one-dimensional quantum gas. It was shown that a well studied phenomenon of Bloch oscillations, usually associated with electrons moving in perisodic lattice, can be observed with mobile impurities in the absence of any lattice potential. Preliminary experimental data obtained in Innsbruck agrees with our predictions. The work on mobile impurities has lead to understanding of dissipation in one-dimensional many-body systems and its extreme sensitivity to the interaction parameters. It has opened perspectives to study mobile impurities experimentally and there are currently several groups around the globe trying to implement these rich systems.
Exploitation Route My results are in the fundamental area of transport and correlations in low dimensional quantum gases and can be used by the scientists (theorists and experimentalists) for their research.
Sectors Education

 
Description My results on correlations of ultracold quantum gases have influenced the corresponding field and my publications attracted over one hundred citations.
First Year Of Impact 2008
Sector Education,Culture, Heritage, Museums and Collections,Other
Impact Types Cultural

 
Description Correlations in expanding gas of hard core bosons 
Organisation Georgia Institute of Technology
Country United States 
Sector Academic/University 
PI Contribution collaboration
Start Year 2008
 
Description Density correlations in one-dimensional gases 
Organisation University of Queensland
Country Australia 
Sector Academic/University 
PI Contribution collaboration
Start Year 2002
 
Description Dynamics and Bloch oscillations of mobile impurities in one-dimensional quantum liquids 
Organisation University of Minnesota
Country United States 
Sector Academic/University 
PI Contribution collaboration
Start Year 2000