This project is funded via the FP7-ICT-2013-X action. The project started in February 2013 and covers the period from February 2013 to January 2016.

The goal of this network is to design a viable solution for the coupling between quantum states in atoms to solid-state quantum devices. The realization of such a quantum interface represents a major breakthrough for information science, as it enables the development of a powerful hybrid architecture, where long-lived states of atoms store quantum information that can be processed rapidly using superconducting quantum circuits. Within such a hybrid approach, the problem of scalability, fast information processing and long-time storage of quantum information can all be solved on a single integrated platform. The major obstacle, thus far, has been to find a suitable quantum interface between atoms (memory) and the surface of the solid-state device (processor), hampered by too low coupling strengths and/or too fast information loss due to fluctuating atom-surface interactions. In this project, we propose to develop and implement a novel approach that solves both of these problems simultaneously. On the one hand, we will make use of the strong microwave transition between highly-excited, atomic Rydberg states to achieve strong coupling to a superconducting stripline cavity. On the other hand, the key point of this proposal is to exploit the enormous interactions between Rydberg atoms for collective encoding of quantum information in large ensembles that will be immunized against parasitic field fluctuations by the strong interactions.

**Figure 1** – *Hybrid quantum information architecture combining an ensemble of atoms (quantum memory) close to a surface and a resonant super-conducting circuit (fast processor). The two systems are coupled by a co-planar waveguide cavity patterned on the surface and the coherent coupling is ensured by controlled excitation of the atoms from the long-lived memory states * *to Rydberg states**. The controlled interaction between Rydberg atoms (U*dd*) will allow us to design collective many-atom states that show enhanced cavity coupling, but which are less sensitive to surface noise.*

#### Consortium

The project gathers five groups within a consortium that combines strong experimental and theoretical expertise in all the necessary areas and contributes complementary setups for state-of-the-art experiments on cold Rydberg atoms and superconducting quantum circuits.

**Institut d’Optique, Palaiseau, France **(coordinating node, P.I. Antoine Browaeys).

**Tübingen University, Germany **(P.I. Jozsef Fortagh).

**Durham University, UK (**P.I. Matthew Jones).

**Nottingham University, UK ** (P.I. Igor Lesanovsky).

**Max Planck Institute for the Physics of Complex Systems, Dresden, Germany **(P.I. Thomas Pohl).

#### News from the project

**January 17/18 2017:**the final workshop of HAIRS takes place at the University of Nottingham. Lots of active discussions!

**June 2016:**the Palaiseau team uses its atom assembler to draw the European Flag with single atoms:

**March 15, 2016:**Antoine Browaeys (coordinator of HAIRS) takes part in the science broadcast “La tête au carré” on the French National Radio (France Inter, ~1 million live listeners). You can listen again to the broadcast here.- March 2016: An article in the magazine
*La Recherche*summarizes the activities of the CNRS-IO group for the general public. Another article in*Reflets de la Physique*(the journal of the French Physics Society) is written for a more specialized audience of physicists. **November 12/13 2015:**the second workshop of the project takes place at the University of Tübingen.**April 7/8th 2014**: the kick-off meeting of the project took place at the Institut d’Optique in Palaiseau, France

### Publications

#### 2017

J.D. Thompson, T. L. Nicholson, Q.-Y. Liang, S. H. Cantu, A. V. Venkatramani, S. Choi, I. A. Fedorov, D. Viscor, T. Pohl, M. D. Lukin, V. Vuletić,

*Symmetry-protected collisions between strongly interacting photons,*

Nature (In press), DOI: 10.1038/nature20823 (2017).

W. Abdussalam, D. Viscor, J. Fortágh, A. Browaeys, T. Lahaye, T. Pohl,

*Protection of a Rydberg atoms-superconducting cavity interface against local noise using dipole-dipole interactions, *

in preparation (2017).

M.Stecker, H. Schefzyk, J. Fortágh, A. Günther,

*A high resolution ion microscope for cold atoms***
**to appear in New J. Phys., arXiv: 1701.02915

P. Federsel, C. Rogulj, T. Menold, Z. Darazs, P. Domokos, A. Günther and J. Fortágh,

*Noise Spectroscopy with a Quantum Gas*

Phys. Rev. A, *under consideration*

J. Grimmel *et al.*,

*Ionization spectra of highly Stark shifted Rubidium Rydberg states*

*i*n preparation, to be submitted to New. J. Phys.

H. Hattermann, D. Bothner, L.Y. Ley, B. Ferdinand, D. Widmayer, L. Sárkány, R. Kleiner, D. Koelle, and J. Fortágh,

*Coupling ultracold atoms to a superconducting coplanar waveguide resonator*

in preparation, to be submitted to Nat. Commun.

M. Marcuzzi, J. Minár, D. Barredo, S. de Léséleuc, H. Labuhn, T. Lahaye, A. Browaeys, E. Levi, and I. Lesanovsky,

*Facilitation Dynamics and Localization Phenomena in Rydberg Lattice Gases with Position Disorder*

Phys. Rev. Lett. **118** 063606 (2017).

B. Everest, I. Lesanovsky, J. P. Garrahan and E. Levi

*Role of interactions in a dissipative many-body localized system*

to appear in Physical Review B (2017), arXiv: 1605.07019.

M. Buchhold, B. Everest, M. Marcuzzi, I. Lesanovsky and S. Diehl

*Nonequilibrium effective field theory for absorbing state phase transitions in driven open quantum spin systems*

to appear in Physical Review B (2017), arXiv: 1611.02283.

R. Gutierrez, C. Simonelli, M. Archimi, F. Castellucci, E. Arimondo, D. Ciampini, M. Marcuzzi, I. Lesanovsky and O. Morsch

*Experimental signatures of an absorbing-state phase transition in an open driven many-body quantum system*

arXiv:1611.03288.

P. Sadler, E. M. Bridge, D. Boddy, A. D. Bounds, N. C. Keegan, G. Lochead, and M. P. A. Jones,

*Radiation trapping in a dense cold Rydberg gas*

Phys. Rev. A **95**, 013839 (2017).

#### 2016

C. R. Murray, A. V. Gorshkov, T. Pohl,

*Many-body decoherence dynamics and optimized operation of a single-photon switch,*

New J. Phys. **18**, 092001 (2016).

F. Maucher, T. Pohl, S. Skupin, W. Krolikowski,

*Self-organization of light in optical media with competing nonlinearities,*

Phys. Rev. Lett. **116**, 163902 (2016).

C. Gaul, B. J. DeSalvo, J. A. Aman, F. B. Dunning, T. C. Killian, and T. Pohl,

*Resonant Rydberg Dressing of Alkaline-Earth Atoms via Electromagnetically Induced Transparency*,

Phys. Rev. Lett. **116**, 243001 (2016).

N. Šibalić, C. G. Wade, C. S. Adams, K. J. Weatherill, and T. Pohl,

*Driven-dissipative many-body systems with mixed power-law interactions: Bistabilities and temperature-driven nonequilibrium phase transitions*,

Phys. Rev. A **94**, 011401(R) (2016).

J. Zeiher, R. van Bijnen, P. Schauß, S. Hild, J. Choi, T. Pohl, I. Bloch, C. Gross,

*Many-body interferometry of a Rydberg-dressed spin lattice,*

Nature Phys. **12**, 1095 (2016).

E. M. Bridge, N. C. Keegan, A. D. Bounds, D. Boddy, D. P. Sadler, and M. P. A. Jones,

*Tunable cw UV laser with Opt. Exp. 24 2281, (2016).*

R. Kliese, N. Hoghooghi, T. Puppe, F. Rohde, A. Sell, A. Zach, P. Leisching, W. Kaenders, N. C. Keegan, A. D. Bounds, E. M. Bridge, J. Leonard, C. S. Adams, S. L. Cornish, M. P.A. Jones,

*Difference-frequency combs in cold atom physic*,

Eur. Phys. J. Spec. Top. 225, 2775 (2016).

E. Levi, J. Minar and I. Lesanovsky

*Crystalline structures in a one-dimensional two-component lattice gas with 1/r^α interactions*

J. Stat. Mech., P033111 (2016).

K. Macieszczak, M. Guta, I. Lesanovsky and J.P. Garrahan

*Dynamical phase transitions as a resource for quantum enhanced metrology*

Phys. Rev. A **93**, 022103 (2016).

B. Everest, M. Marcuzzi and I. Lesanovsky

*Atomic loss and gain as a resource for non-equilibrium phase transitions in optical lattices*

Phys. Rev. A **93**, 023409 (2016). Editor’s Suggestion.

M. M. Valado, C. Simonelli, M. D. Hoogerland, I. Lesanovsky, J.P. Garrahan, E. Arimondo, D. Ciampini and O. Morsch

*Experimental observation of controllable kinetic constraints in a cold atomic gas*

Phys. Rev. A **93**, 040701 (2016). Editor’s Suggestion

E. Levi, M. Heyl, I. Lesanovsky and J.P. Garrahan

*Robustness of many-body localization in the presence of dissipation*

Phys. Rev. Lett. 116, 237203 (2016).

K. Macieszczak, M. Guta, I. Lesanovsky and J.P. Garrahan

*Towards a theory of metastability in open quantum dynamics*

Phys. Rev. Lett. **116**, 240404 (2016).

M. Marcuzzi, M. Buchhold, S. Diehl and I. Lesanovsky

*Absorbing state phase transition with competing quantum and classical fluctuations*

Phys. Rev. Lett. 116, 245701 (2016).

H. Gorniaczyk, C. Tresp, P. Bienias, A. Paris-Mandoki, W. Li, I. Mirgorodskiy, H. P. Büchler, I. Lesanovsky and S. Hofferberth

*Enhancement of Rydberg-mediated single-photon nonlinearities by electrically tuned Förster resonances*

Nature Comm. **7**, 12480 (2016).

E. Levi, R. Gutierrez and I. Lesanovsky

*Quantum non-equilibrium dynamics of Rydberg gases in the presence of dephasing noise of different strengths*

J. Phys. B **49**, 184003 (2016).

R. Gutierrez, J.P. Garrahan and I. Lesanovsky

*Non-equilibrium fluctuations and metastability arising from non-additive interactions in dissipative multi-component Rydberg gases*

New J. Phys. **18**, 093054 (2016).

B. Everest, M. Marcuzzi, J. P. Garrahan and I. Lesanovsky

*Emergent kinetic constraints, ergodicity breaking, and cooperative dynamics in noisy quantum systems*

Phys. Rev. E **94**, 052108 (2016).

D. C. Rose, K. Macieszczak, I. Lesanovsky and J. P. Garrahan

*Metastability in an open quantum Ising model*

Phys. Rev. E **94**, 052132 (2016).

Z. Lan, W. Li and I. Lesanovsky

*Quantum melting of two-component Rydberg crystals*

Phys. Rev. A **94**, 051603 (2016).

R. Stevenson, J. Minář, S. Hofferberth, I. Lesanovsky,

*Prospects of charged-oscillator quantum-state generation with Rydberg atoms*

Phys. Rev. A **94**, 043813 (2016).

J. Minář, S. G. Söyler, I. Lesanovsky

*Non-equilibrium dynamics of non-linear Jaynes-Cummings model in cavity arrays*

New J. Phys. **18**, 053035 (2016).

D. Barredo, S. de Léséleuc, V. Lienhard, T. Lahaye, and A. Browaeys,

*An atom-by-atom assembler of defect-free arbitrary 2d atomic arrays*,

Science 354, 1021 (2016).

A. Browaeys, D. Barredo, and T. Lahaye,

*Experimental investigations of the dipolar interactions between a few individual Rydberg atoms*,

J. Phys. B **49**, 152001 (2016).

H. Labuhn, D. Barredo, S. Ravets, S. de Léséleuc, T. Macrì, T. Lahaye and A. Browaeys,

*Tunable two-dimensional arrays of single Rydberg atoms for realizing quantum Ising models*,

Nature** 534**, 667 (2016).

H. Labuhn,

*Creating arbitrary 2D arrays of single atoms for the simulation of spin systems with Rydberg states
*Eur. Phys. J. ST

**225**, 2817 (2016).

**2015**

C. L. Vaillant, R. M. Potvliege, and M. P. A. Jones,

*Intercombination effects in resonant energy transfer,*

Phys. Rev. A **92**, 042705 (2015).

L.Sárkány, J.Fortágh, D.Petrosyan,

*Long-range quantum gate via Rydberg states of atoms in a thermal microwave cavity***
**Phys. Rev. A

**92**, 030303 (R) (2015).

P. Federsel, C. Rogulj, T. Menold, J. Fortágh, and A. Günther,

*Spectral response of magnetically trapped Bose gases to weak microwave fields*

Phys. Rev. A** 92**, 033601 (2015).

M. Mack, J. Grimmel, F. Karlewski, L. Sárkány, H. Hattermann, and J. Fortágh,

*All-optical measurement of Rydberg state lifetimes,*

Phys. Rev. A **92**, 012517 (2015).

W. Li and I. Lesanovsky

*Coherence in a cold atom photon switch*

Phys. Rev. A **92**, 043828 (2015).

Z. Lan, J. Minar, E. Levi, W. Li and I. Lesanovsky

*Emergent devil’s staircase without particle-hole symmetry in Rydberg quantum gases with competing attractive and repulsive interactions*

Phys. Rev. Lett. **115**, 203001 (2015).

E. Levi, J. Minar, J.P. Garrahan and I. Lesanovsky

*Crystalline structures and frustration in a two-component Rydberg gas*

New J. Phys. **17**, 123017 (2015).

R. Gutierrez, J.P. Garrahan and I. Lesanovsky

*Self-similar nonequilibrium dynamics of a many-body system with power-law interactions*

Phys. Rev. E **92**, 062144 (2015).

A. Sanayei, N. Schopohl, J. Grimmel, M. Mack, F. Karlewski, and J. Fortágh,

*Quasiclassical theory of quantum defect and spectrum of highly excited rubidium atoms*

Phys. Rev. A **91**, 032509 (2015).

F. Karlewski, M. Mack, J. Grimmel, N. Sándor, and J. Fortágh,

*State-selective all-optical detection of Rydberg atoms*

Phys. Rev. A **91**, 043422 (2015).

R. M. W. van Bijnen and T. Pohl,

Q*uantum magnetism and topological ordering via Rydberg-dressing near Forster-resonances,* Phys. Rev. Lett. **114**, 243002 (2015).

M. F. Maghrebi, N. Y. Yao, M. Hafezi, T. Pohl, O. Firstenberg and A. V. Gorshkov,

*Fractional Quantum Hall States of Rydberg Polaritons,*

Phys. Rev. A **91**, 033838 (2015).

A. Urvoy, F. Ripka, I. Lesanovsky, D. Booth, J.P. Shaffer, T. Pfau and R. Löw,

S*trongly correlated growth of Rydberg aggregates in a vapour cell*

Phys. Rev. Lett. **114**, 203002 (2015). Editor’s suggestion.

M. Marcuzzi, E. Levi, W. Li, J.P. Garrahan, B. Olmos, and I. Lesanovsky,

*Non-equilibrium universality in the dynamics of dissipative cold atomic gases*

New J. Phys. **17**, 072003 (2015) .

P. Schauß, J. Zeiher, T. Fukuhara, S. Hild, M. Cheneau, T. Macrì,T. Pohl, I. Bloch and C. Gross,

*Crystallization in Ising quantum magnets*

Science **347**, 1455 (2015).

J. Grimmel, M. Mack, F. Karlewski, F. Jessen, M. Reinschmidt, N. Sándor, J. Fortágh,

*Measurement and numerical calculation of Rubidium Rydberg Stark spectra*

New J. Phys. 17 053005 (2015).

S. Ravets, H. Labuhn, D. Barredo, T. Lahaye, and A. Browaeys,

*Measurement of the angular dependence of the dipole-dipole interaction between two individual Rydberg atoms at a Förster resonance*

Phys. Rev. A **92** 020701(R) (2015). Editor’s suggestion.

D. Viscor, W. Li and I. Lesanovsky,

*Electromagnetically induced transparency of a single-photon in dipole-coupled one-dimensional atomic clouds *

* *New J. Phys. **17**, 033007 (2015).

D. Barredo, H. Labuhn, S. Ravets, T. Lahaye, A. Browaeys, C. S. Adams,

*Coherent Excitation Transfer in a Spin Chain of Three Rydberg Atoms*

* *Phys. Rev. Lett.** 114**, 113002 (2015).

**2014**

L. Vaillant, M. P. A. Jones and R. M. Potvliege ,

*Multichannel quantum defect theory of strontium bound Rydberg state*,

J. Phys. B **47**, 155001 (2014).

L. I. Gil, R. Mukherjee, E. M. Bridge, M. P. A. Jones and T. Pohl,

*Spin squeezing in a Rydberg lattice clock, *

Phys. Rev. Lett. **112**, 103601 (2014).

S. Sevinçli and T. Pohl,

*Microwave control of Rydberg atom interactions, *

New J. Phys. **16**, 123036 (2014).

M. Hoening, W. Abdussalam, M. Fleischhauer, T. Pohl,

*Antiferromagnetic long-range order in dissipative Rydberg lattices *

* *Phys. Rev. A **90**, 021603(R) (2014).

L. Sárkány, P. Weiss, H. Hattermann, and J. Fortágh

*Controlling the magnetic-field sensitivity of atomic-clock states by microwave dressing*

* *Phys. Rev. A **90**, 053416 (2014)

E. Levi and I. Lesanovsky

*Non-classical correlations in a class of spin chains with long-range interactions and exactly solvable ground states*

* *New J. Phys. **16**, 093053 (2014)

B. Olmos, I. Lesanovsky and J. P. Garrahan

*Out-of-equilibrium evolution of kinetically constrained many-body quantum systems under purely dissipative dynamics*

* *Phys. Rev. E **90**, 042147 (2014)

M. Marcuzzi, E. Levi, S. Diehl, J. P. Garrahan and I. Lesanovsky

*Universal nonequilibrium properties of dissipative Rydberg gases*

* *Phys. Rev. Lett. **113**, 210401 (2014)

M. Marcuzzi, J. Schick, B. Olmos and I. Lesanovsky

*Effective dynamics of strongly dissipative Rydberg gases*

* *J. Phys A **47**, 482001 (2014)

D. Cano and J. Fortagh,

*Multiatom entanglement in cold Rydberg mixtures, *

Phys. Rev. A **89**, 043413 (2014)

H. Labuhn, S. Ravets, D. Barredo, L. Béguin, F. Nogrette, T. Lahaye, and A. Browaeys,

*Single-atom addressing in microtraps for quantum-state engineering using Rydberg atoms,*

Phys.Rev. A **90**, 023415 (2014)

S. Ravets, H. Labuhn, D. Barredo, L. Béguin, T. Lahaye, A. Browaeys,

*Coherent dipole-dipole coupling between two single atoms at an electronically tuned Förster resonance*

Nature Phys., **10** 914 (2014).

D. Barredo, S. Ravets, H. Labuhn, L. Béguin, A. Vernier, F. Nogrette, T. Lahaye, A. Browaeys,

*Demonstration of a strong Rydberg Blockade in three-atom systems with anisotropic interactions, *

Phys. Rev. Lett.** 112** 183002 (2014)

F. Nogrette, H. Labuhn, S. Ravets, D. Barredo, L. Béguin, A. Vernier, T. Lahaye and A. Browaeys,

*Single atom trapping in holographic 2D arrays of microtraps with arbitrary geometries,*

Phys. Rev. X **4** 021034 (2014)