487 citations · 2.3k across the 20 of their papers we have counts for
15 papers · 1 filter
Entanglement between Distant Macroscopic Mechanical and Spin Systems
Rodrigo A. Thomas, Michał Parniak, Christoffer Østfeldt +7
Entanglement is a vital property of multipartite quantum systems, characterised by the inseparability of quantum states of objects regardless of their spatial separation. Generatio…
Observation of quantum spin noise in a 1D light-atoms quantum interface
J. -B. Béguin, J. H. Müller, J. Appel +1
We observe collective quantum spin states of an ensemble of atoms in a one-dimensional light-atom interface. Strings of hundreds of cesium atoms trapped in the evanescent fiel of a…
Multi-partite entanglement detection with non symmetric probing
Luca Dellantonio, Sumanta Das, Jürgen Appel +1
We show that spin squeezing criteria commonly used for entanglement detection can be erroneous, if the probe is not symmetric. We then derive a lower bound on squeezing for separab…
Generation and detection of a sub-Poissonian atom number distribution in a one-dimensional optical lattice
J. -B. Béguin, E. Bookjans, S. L. Christensen +4
We demonstrate preparation and detection of an atom number distribution in a one-dimensional atomic lattice with the variance dB below the Poissonian noise level. A mesoscopi…
Quantum interference of a single spin excitation with a macroscopic atomic ensemble
S. L. Christensen, J. -B. Béguin, E. Bookjans +4
We report on the observation of quantum interference of a collective single spin excitation with a spin ensemble of atoms. Detection of a single photon scat…
Towards quantum state tomography of a single polariton state of an atomic ensemble
S. L. Christensen, J. B. Béguin, H. L. Sørensen +5
We present a proposal and a feasibility study for the creation and quantum state tomography of a single polariton state of an atomic ensemble. The collective non-classical and non-…
Atomic nonclassicality quasiprobabilities
T. Kiesel, W. Vogel, S. L. Christensen +3
Although nonclassical quantum states are important both conceptually and as a resource for quantum technology, it is often difficult to test whether a given quantum system displays…
Quantum Memories. A Review based on the European Integrated Project "Qubit Applications (QAP)"
C. Simon, M. Afzelius, J. Appel +21
We perform a review of various approaches to the implementation of quantum memories, with an emphasis on activities within the quantum memory sub-project of the EU Integrated Proje…
Entanglement-assisted atomic clock beyond the projection noise limit
Anne Louchet-Chauvet, Jürgen Appel, Jelmer J. Renema +3
We use a quantum non-demolition measurement to generate a spin squeezed state and to create entanglement in a cloud of 10^5 cold cesium atoms, and for the first time operate an ato…
Squeezing of Atomic Quantum Projection Noise
Patrick J. Windpassinger, Daniel Oblak, Ulrich B. Hoff +4
We provide a framework for understanding recent experiments on squeezing of a collective atomic pseudo-spin, induced by a homodyne measurement on off-resonant probe light interroga…
Versatile Digital GHz Phase Lock for External Cavity Diode Lasers
Jürgen Appel, Andrew MacRae, A. I. Lvovsky
We present a versatile, inexpensive and simple optical phase lock for applications in atomic physics experiments. Thanks to all-digital phase detection and implementation of beat f…
Spin squeezing of atomic ensembles by multi-colour quantum non-demolition measurements
M. Saffman, D. Oblak, J. Appel +1
We analyze the creation of spin squeezed atomic ensembles by simultaneous dispersive interactions with several optical frequencies. A judicious choice of optical parameters enables…
Non-Destructive Probing of Rabi Oscillations on the Cesium Clock Transition near the Standard Quantum Limit
P. J. Windpassinger, D. Oblak, P. G. Petrov +7
We report on non-destructive observation of Rabi oscillations on the Cs clock transition. The internal atomic state evolution of a dipole-trapped ensemble of cold atoms is inferred…
Quantum memory for squeezed light
Juergen Appel, Eden Figueroa, Dmitry Korystov +2
We produce a 600-ns pulse of 1.86-dB squeezed vacuum at 795 nm in an optical parametric amplifier and store it in a rubidium vapor cell for 1 us using electromagnetically induced t…
Adiabatic frequency conversion of quantum optical information in atomic vapor
Frank Vewinger, Juergen Appel, Eden Figueroa +1
We experimentally demonstrate a quantum communication protocol that enables frequency conversion and routing of quantum optical information in an adiabatic and thus robust way. The…