Quasiparticle Dynamics in a Bose Insulator Probed by Interband Bragg Spectroscopy

Nicole Fabbri (1) , Sebastian Huber (2) , David Clément (3, 1) , Leonardo Fallani (1) , Chiara Fort (1) , Massimo Inguscio (1) , Ehud Altman (2)

1 LENS - European Laboratory for Non-Linear Spectroscopy
2 Weizmann Institute of Science [Rehovot, Israël]
3 Laboratoire Charles Fabry / Optique atomique

We investigate experimentally and theoretically the dynamical properties of a Mott insulator in decoupled one-dimensional chains. Using a theoretical analysis of the Bragg excitation scheme, we show that the spectrum of interband transitions holds information on the single-particle Green's function of the insulator. In particular, the existence of particle-hole coherence due to quantum fluctuations in the Mott state is clearly seen in the Bragg spectra and quantified. Finally, we propose a scheme to directly measure the full, momentum-resolved spectral function as obtained in the angle-resolved photoemission spectroscopy of solids.

Domaines: Matière Molle [cond-mat.soft]

Nicole Fabbri, Sebastian Huber, David Clément, Leonardo Fallani, Chiara Fort, et al.. Quasiparticle Dynamics in a Bose Insulator Probed by Interband Bragg Spectroscopy. Physical Review Letters, 2012, 109 (5), http://link.aps.org/doi/10.1103/PhysRevLett.109.055301. ⟨10.1103/PhysRevLett.109.055301⟩. ⟨hal-00726041⟩