H2020

Quantum Spin Lenses in Atomic Arrays

Date: 
2017-09-20
Author(s): 

A. Glätzle, K. Ender, D. S. Wild, S. Choi, H. Pichler, M. Lukin, P. Zoller

Reference: 

Phys. Rev. X 7, 31049 (2017)

We propose and discuss quantum spin lenses, where quantum states of delocalized spin excitations in an atomic medium are focused in space in a coherent quantum process down to (essentially) single atoms. These can be employed to create controlled interactions in a quantum light-matter interface, where photonic qubits stored in an atomic ensemble are mapped to a quantum register represented by single atoms. We propose Hamiltonians for quantum spin lenses as inhomogeneous spin models on lattices, which can be realized with Rydberg atoms in 1D, 2D, and 3D, and with strings of trapped ions.

Anisotropic polarizability of erbium atoms

Date: 
2018-01-19
Author(s): 

J. H. Becher, S. Baier, K. Aikawa, M. Lepers, J.-F. Wyart, O. Dulieu, and F. Ferlaino

Reference: 

10.1103/PhysRevA.97.012509

We report on the determination of the dynamical polarizability of ultracold erbium atoms in the ground and in one excited state at three different wavelengths, which are particularly relevant for optical trapping. Our study combines experimental measurements of the light shift and theoretical calculations. In particular, our experimental approach allows us to isolate the different contributions to the polarizability, namely, the isotropic scalar and anisotropic tensor part.

Observation of the Roton Mode in a Dipolar Quantum Gas

Date: 
2017-05-19
Author(s): 

Lauriane Chomaz, Rick M. W. van Bijnen, Daniel Petter, Giulia Faraoni, Simon Baier, Jan Hendrik Becher, Manfred J. Mark, Falk Waechtler, Luis Santos, Francesca Ferlaino

Reference: 

arXiv:1705.06914

The concept of a roton, a special kind of elementary excitation, forming a minimum of energy at finite momentum, has been essential to understand the properties of superfluid

Outreach event: Celebrate Science fair at Durham University (24th - 26th October 2017)

The Durham Atomic and Molecular Physics group run an interactive activity focussing on optical communications and fibres aimed at primary school children which was part of Durham University's annual "Celebrate Science" fair.

Outreach activity: Saturday Morning Physics "The Mystery and Mastery of Photons" (talk by Charles Adams and interactive experiments at Durham University, 18th November 2017)

The event was part of the "Saturday morning Physics"-series hosted by the Durham Physics department and featured a talk by Prof. Charles Adams aimed at the general public followed by a series of hands-on demonstrations and labtours.

A high repetition rate experimental setup for quantum non-linear optics with cold Rydberg atoms

Date: 
2016-12-19
Author(s): 

Hannes Busche, Simon W. Ball, Paul Huillery

Reference: 

Eur. Phys. J. Special Topics 225, 2839-2861 (2016)

sing electromagnetically induced transparency and photon storage, the strong dipolar interactions between Rydberg atoms and the resulting dipole blockade can be mapped onto light fields to realise optical non-linearities and interactions at the single photon level. We report on the realisation of an experimental apparatus designed to study interactions between single photons stored as Rydberg excitations in optically trapped microscopic ensembles of ultracold 87Rb atoms.

Calculation of Rydberg interaction potentials

Date: 
2017-06-12 - 2018-02-12
Author(s): 

Sebastian Weber, Christoph Tresp, Henri Menke, Alban Urvoy, Ofer Firstenberg, Hans Peter Büchler, and Sebastian Hofferberth

Reference: 

Journal of Physics B: Atomic, Molecular and Optical Physics, Volume 50, Number 13 (2017)

The strong interaction between individual Rydberg atoms provides a powerful tool exploited in an ever-growing range of applications in quantum information science, quantum simulation and ultracold chemistry. One hallmark of the Rydberg interaction is that both its strength and angular dependence can be fine-tuned with great flexibility by choosing appropriate Rydberg states and applying external electric and magnetic fields.

Exploring quantum phases by driven dissipation

Date: 
2015-07-29
Author(s): 

Nicolai Lang and Hans Peter Büchler

Reference: 

Phys. Rev. A 92, 012128 (2015)

Dephasing and decay are the intrinsic dissipative processes prevalent in any open quantum system and the dominant mechanisms for the loss of coherence and entanglement. This inadvertent effect not only can be overcome but can even be capitalized on in a dissipative quantum simulation by means of tailored couplings between the quantum system and the environment.

Controlling Stray Electric Fields on an Atom Chip for Rydberg Experiments

Date: 
2017-10-15
Author(s): 

D. Davtyan, S. Machluf, M. L. Soudijn, J. B. Naber, N. J. van Druten, van Linden van den Heuvell, R. J. C. Spreeuw

Reference: 

arXiv:1710.05301

Experiments handling Rydberg atoms near surfaces must necessarily deal with the high sensitivity of Rydberg atoms to (stray) electric fields that typically emanate from adsorbates on the surface. We demonstrate a method to modify and reduce the stray electric field by changing the adsorbates distribution. We use one of the Rydberg excitation lasers to locally affect the adsorbed dipole distribution.

Trapping of Rydberg atoms in tight magnetic microtraps

Date: 
2018-01-31
Author(s): 

A. G. Boetes, R. V. Skannrup, J. Naber, S. J. J. M. F. Kokkelmans, and R. J. C. Spreeuw

Reference: 

PHYSICAL REVIEW A 97, 013430 (2018)

We explore the possibility to trap Rydberg atoms in tightly confining magnetic microtraps. The trapping frequencies for Rydberg atoms are expected to be influenced strongly by magnetic-field gradients. We show that there are regimes where Rydberg atoms can be trapped. Moreover, we show that so-called magic trapping conditions can be found for certain states of rubidium, where both Rydberg atoms and ground-state atoms have the same trapping frequencies. Magic trapping is highly beneficial for implementing quantum gate operations that require long operation times.

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