ResearchResearch Area A
Research propject A04

Project A04: Controlling polar molecules in optical lattices

The aim of project A04 is to reveal the novel physics introduced by the dipole-dipole interactions in the many-body dynamics of polar lattice gases, as well as to develop new ideas for the control of polar molecules in optical lattices, including cooling, detection and preparation techniques. During the first years of DQmat, we have revealed novel quasi-localization mechanisms in disorderless polar lattice gases, as well as anomalous localization and multi-fractality in dipole-induced pseudo-spin transport. Furthermore, together with A03, we have designed novel methods for detection, entanglement, and dissipative state engineering of polar molecules using atoms.

INTRODUCTION

Research on ultra-cold atoms in optical lattices has quickly developed in recent years, establishing itself as a new cross-disciplinary field at the interface between condensed-matter and AMO physics. Experiments have mostly focused up to now on atomic gases with short-range isotropic interactions. However, a new generation of experiments on magnetic atoms, polar molecules, and Rydberg gases is starting to reveal the physics resulting from the dipole-dipole interaction. Contrary to their non-polar counterparts, polar lattice gases present significant or even dominant inter-site interactions. As a result, these gases, and in particular polar molecules in optical lattices, constitute a promising scenario for the quantum simulation of extended Hubbard models and spin Hamiltonians.

However, the present control of polar molecules lags behind that of atomic gases, and a number of challenging issues must be addressed in order to fully reveal this fascinating physics. The long-term vision of this theory project is to develop new ideas for the control of polar molecules in optical lattices, including cooling techniques that consider specifically the non-equilibrium features of polar lattice gases, and the preparation of interesting many-body states, with a particular emphasis on correlated states with metrological applications.

RESULTS

Within the first funding period we focus on the non-equilibrium dynamics of polar lattice gases, as well as on novel detection and dissipative engineering methods for polar molecules.

Polar molecules in an optical lattice present an intricate non-equilibrium physics. They may either physically move from one site to a neighboring one (Hubbard dynamics) or rotational excitations may be transferred amongst pinned molecules (spin dynamics). These dynamics and the preparation and detection of interesting states of polar molecules in lattices constitute the focus of project A04.

Concerning the former, we have studied both Hubbard and spin dynamics. Mobile polar particles in a deep optical lattice may be described with extended Hubbard models. We have recently shown that the combination of energy conservation, finite energy bandwidth, and dipolar interactions results in self-bound lattice droplets, as well as quasi-localization in absence of disorder due to the formation of anomalously long-lived clusters of dynamically-bound inter-site dimers. Pinned polar molecules in a lattice may encode a pseudo-spin degree of freedom in their rotational states. Spin excitations may propagate amongst the particles, resulting in peculiar disorder models when the lattice is partially filled (the typical case). We have shown that these excitations present peculiar transport properties, characterized by the existence of multifractal states, which are neither localized nor ergodic. Moreover, we have extended our analysis to other power-law interactions, as those available in ion traps, revealing as well exotic localization properties.

We have also studied the control of polar molecules through interactions with atoms. Ultracold polar molecules can undergo strong chemical reactions with atoms, which can provide a dissipative interaction mechanism. In the quantum Zeno regime, this interaction can be used for the detection and entanglement of molecules, as well for the controlled dissipation of rotational excitations.

FUTURE

Our analysis of spin dynamics in pinned polar lattice gases has mostly focus on single excitations, which may be considered as single-particle system. In the next future we will extend our analysis to many spin excitations, which formed a many-body system of effective hard-core bosons. We plan to reveal many-body localization features, and how the effective spin hopping induced by power-law interactions affects entanglement propagation and correlation properties of the quantum many-body system. We will study as well Hubbard dynamics, including two-dimensional polar lattice gases and the quasi-adiabatic creation of interesting many-body states, in particular the Haldane insulator.

Additionally, we will investigate the prospects of polar molecules under driving and dissipation. We will develop new techniques for Floquet engineering of many-body interactions using continuous dynamical decoupling and recoupling sequences. We will be especially interested in the realization of topological states of matter and investigate their possibilities for metrological applications.


PUBLICATIONS

  • L. Tanzi, E. Lucioni, F. Famà, J. Catani, A. Fioretti, C. Gabbanini, R. N. Bisset, L. Santos, and G. Modugno (2019): Observation of a Dipolar Quantum Gas with Metastable Supersolid PropertiesPhys. Rev. Lett. 122, 130405
    DOI: 10.1103/PhysRevLett.122.130405
  • X. Deng, S. Ray, S. Sinha, G. V. Shlyapnikov, and L. Santos (2019): One-Dimensional Quasicrystals with Power-Law HoppingPhys. Rev. Lett. 123, 025301
    DOI: /10.1103/PhysRevLett.123.025301
  • Jamadagni, A.; Weimer, H.; Bhattacharyya, A. (2018): Robustness of topological order in the toric code with open boundariesPhys. Rev. B 98, 235147
    DOI: 10.1103/PhysRevB.98.235147
  • Raghunandan, M.; Wrachtrup, J.; Weimer, H. (2018): High-Density Quantum Sensing with Dissipative First Order TransitionsPhys. Rev. Lett. 120, 150501
    DOI: 10.1103/PhysRevLett.120.150501
  • Roghani, M.; Weimer, H. (2018): Dissipative preparation of entangled many-body states with Rydberg atomsQuantum Sci. Technol. 3, 035002
    DOI: 10.1088/2058-9565/aab3f3
  • Kshetrimayum, Augustine; Weimer, Hendrik; Orus, Roman (2017): A simple tensor network algorithm for two-dimensional steady statesNature Communicationsvolume 8, 1291
    DOI: 10.1038/s41467-017-01511-6
  • Overbeck, V. R.; Maghrebi, M. F.; Gorshkov, A. V.; Weimer, H. (2017): Multicritical behavior in dissipative Ising modelsPhys. Rev. A 95, 042133
    DOI: 10.1103/PhysRevA.95.042133
  • Weimer, H. (2017): Tailored jump operators for purely dissipative quantum magnetismJ. Phys. B: At. Mol. Opt. Phys. 50, 024001
    DOI: 10.1088/1361-6455/50/2/024001
  • Kaczmarczyk, J.; Weimer, H.; Lemeshko, M. (2016): Dissipative preparation of antiferromagnetic order in the Fermi-Hubbard modelNew J. Phys. 18, 093042
    DOI: 10.1088/1367-2630/18/9/093042
  • Lammers, J.; Weimer, H.; Hammerer, K. (2016): Open-system many-body dynamics through interferometric measurements and feedbackPhys. Rev. A 94, 052120
    DOI: 10.1103/PhysRevA.94.052120
All publications of the Collaborative Research Centre

PROJECT LEADER

PD Dr. Hendrik Weimer
Address
Appelstraße 2
30167 Hannover
Building
Room
211
Address
Appelstraße 2
30167 Hannover
Building
Room
211
Prof. Dr. Luis Santos
Address
Appelstraße 2
30167 Hannover
Building
Room
249
Address
Appelstraße 2
30167 Hannover
Building
Room
249

STAFF

Dr. Xiaolong Deng
Address
Appelstraße 2
30167 Hannover
Building
Room
247
Dr. Xiaolong Deng
Address
Appelstraße 2
30167 Hannover
Building
Room
247
Dr. Arya Dhar
Address
Appelstraße 2
30167 Hannover
Building
Room
248
Dr. Arya Dhar
Address
Appelstraße 2
30167 Hannover
Building
Room
248
M. Sc. Wei-Han Li
Address
Appelstraße 2
30167 Hannover
Building
Room
244
M. Sc. Wei-Han Li
Address
Appelstraße 2
30167 Hannover
Building
Room
244
M. Sc. Amit Jamadagni Gangapuram
Address
Appelstraße 2
30167 Hannover
Building
Room
210
M. Sc. Amit Jamadagni Gangapuram
Address
Appelstraße 2
30167 Hannover
Building
Room
210
M. Sc. Meghana Raghunandan
Address
Appelstraße 2
30167 Hannover
Building
Room
M. Sc. Meghana Raghunandan
Address
Appelstraße 2
30167 Hannover
Building
Room