Probing cold atoms

The use of cold atoms in simulating interesting open questions of condensed matter physics has seen a tremendous success in recent years [1]. One key aspect is their almost perfect isolation from the environment. What proofs to be an asset in implementing a “designed” Hamiltonian turns out to be a major obstruction to the investigation of the resulting physics.

In our research we focus on the development of the theoretical framework for new investigative tools adapted to the cold atoms setup. We are mainly interested in strongly correlated lattice systems where we showed how to extract coherence porperties from a bosonic or fermionic Mott insulator [2,3]. Moreover, we pointed out how the “Higgs mode” close to a quantum phase transition can be measured [4,5]. Recent experiments verified our predictions [6]. We make use of a broad range of analytical tools, however, if necessary we develop new approaches to tackle the many-body problems at hand [7].

Another consequence of the high degree of isolation is the ability to study pure non-equilibrium dynamics. In the past we studied mainly one-dimensional systems, in particular coupled tubes of interacting quantum liquids that undergo quantum quenches [8] or slow Landau-Zener dyanamics [9].

We plan to extend these studies by investigating the non-equilibrium dynamics of strongly correlated systems, in particular their topological properties. We believe that by focusing on the peculiarities  of new engineered quantum systems like cold atoms or micro-structured solid state devices like NV centers in diamonds, coupled microwave cavities, etc., we can make new discoveries in a developing field of topological phases out of equilibrium.

[1] I. Bloch, J. Dalibard, W. Zwerger, Rev. Mod. Phys., 80 885 (2008) URL
[2] N Fabbri, S.D. Huber et al., Phys. Rev. Lett., 109 055301 (2012) URL
[4] S. D. Huber, E. Altman, H. P. Büchler, G. Blatter, Phys. Rev. B, 75 085106 (2007) URL
[5] S. D. Huber, B. Theiler, E. Altman, G. Blatter, Phys. Rev. Lett., 100 050404 (2008) URL
[6] M. Endres et al, Nature, 487 454 (2012) URL
[7] A. Rüegg, S. D. Huber, M. Sigrist, Phys. Rev. B, 81 155118 (2010) URL
[8] S. D. Huber, E. Altman, Phys. Rev. Lett., 103 160402 (2009) URL
[9] Y.-A. Chen, S. D. Huber, S. Trotzky, I. Bloch, E. Altman, Nature Phys., 7 61 (2011) URL