# Momentum-space atom correlations of interacting lattice bosons

When |
Feb 13, 2020
from 01:30 PM to 02:30 PM |
---|---|

Where | Amphithèâtre E |

Attendees |
David Clément |

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# Jeudi 13 Février

## Title: Momentum-space atom correlations of interacting lattice bosons

# David Clément (Institute d'Optique, Palaiseau)

**Abstract: **

Measuring the full distribution of individual quantum particles has emerged as a central approach to characterize many-body ground-states and many-body dynamics by means of correlation functions. Over the past decade, various platforms, from trapped ions and superconducting circuits to arrays of cold atoms, have investigated strongly interacting matter through position-space and/or spin-resolved correlations. In this talk I will present a complementary approach that consists in measuring the momentum-space correlations between quantum particles. This is achieved by detecting individual metastable Helium-4 atoms in three dimensions and in the far-field regime of expansion, when released from an optical lattice.

I will briefly discuss the benchmarking of our technique with ab-initio quantum Monte-Carlo calculations [1] and the investigation of two-body collisions during the expansion [2]. Then I will report on the measurement of the two-body and three-body correlations deep in the Mott insulator regime. We observe a perfectly contrasted bunching whose periodicity reproduces the reciprocal lattice. In addition, we show quantitatively that the momentum-space correlations of a Mott insulator are of Gaussian nature [3]. Finally, I will present a recent observation of a Hanbury-Brown and Twiss type of experiment with strongly-interacting lattice Bose-Einstein condensates [4]. The interpretation of the measured bunching in the depletion of the condensate is found compatible with that expected for Bogoliubov quasi-particles.

[1] H. Cayla, C. Carcy, Q. Bouton, R. Chang, G. Carleo, M. Mancini, D. Clément, Phys. Rev. A 97 061609(R) (2018)

[2] A. Tenart, C. Carcy, C. Carcy, H. Cayla, T. Bourdel, M. Mancini, D. Clément, Phys. Rev. Research 2, 013017 (2020)

[3] C. Carcy, H. Cayla, A. Tenart, A. Aspect, M. Mancini, D. Clément, Phys. Rev. X 9, 041028 (2019)

[4] In preparation (2020).