Publications (58)
Nuclear spin squeezing in Helium-3 by continuous quantum nondemolition measurement
Alan Serafin, Matteo Fadel, Philipp Treutlein +1
We propose a technique to control the macroscopic collective nuclear spin of a Helium-3 vapor in the quantum regime using light. The scheme relies on metastability exchange collisi…
Entanglement between identical particles is a useful and consistent resource
Benjamin Morris, Benjamin Yadin, Matteo Fadel +3
The existence of fundamentally identical particles represents a foundational distinction between classical and quantum mechanics. Due to their exchange symmetry, identical particle…
Quantum metrology with nonclassical states of atomic ensembles
Luca Pezzè, Augusto Smerzi, Markus K. Oberthaler +2
Quantum technologies exploit entanglement to revolutionize computing, measurements, and communications. This has stimulated the research in different areas of physics to engineer a…
Coherent feedback cooling of a nanomechanical membrane with atomic spins
Gian-Luca Schmid, Chun Tat Ngai, Maryse Ernzer +3
Coherent feedback stabilises a system towards a target state without the need of a measurement, thus avoiding the quantum backaction inherent to measurements. Here, we employ optic…
Remote Hamiltonian Interactions Mediated by Light
Thomas M. Karg, Baptiste Gouraud, Klemens Hammerer +1
We address a fundamental question of quantum optics: Can a beam of light mediate coherent Hamiltonian interactions between two distant quantum systems? This is an intriguing questi…
Quantum metrology with a scanning probe atom interferometer
Caspar F. Ockeloen, Roman Schmied, Max F. Riedel +1
We use a small atomic Bose-Einstein condensate as an interferometric scanning probe to map out a microwave field near a chip surface with a few micrometers resolution. Using entang…
Coupling ultracold atoms to mechanical oscillators
David Hunger, Stephan Camerer, Maria Korppi +3
In this article we discuss and compare different ways to engineer an interface between ultracold atoms and micro- and nanomechanical oscillators. We start by analyzing a direct mec…
Enhanced and reduced atom number fluctuations in a BEC splitter
Kenneth Maussang, G. Edward Marti, Tobias Schneider +6
We measure atom number statistics after splitting a gas of ultracold 87Rb atoms in a purely magnetic double-well potential created on an atom chip. Well below the critical temperat…
Nuclear spin squeezing by continuous quantum non-demolition measurement: a theoretical study
Alan Serafin, Yvan Castin, Matteo Fadel +2
We propose to take advantage of the weak coupling of ground-state helium-3 nuclear spin to its environment to produce long-lived macroscopic quantum states, nuclear spin squeezed s…
Prospects for storage and retrieval of a quantum dot single photon in an ultracold Rb ensemble
Matthew T. Rakher, Richard J. Warburton, Philipp Treutlein
Epitaxially grown quantum dots (QDs) are promising sources of non-classical states of light such as single photons and entangled photons. However, in order for them to be used as a…
Does a large quantum Fisher information imply Bell correlations?
Florian Fröwis, Matteo Fadel, Philipp Treutlein +2
The quantum Fisher information (QFI) of certain multipartite entangled quantum states is larger than what is reachable by separable states, providing a metrological advantage. Are…
Spectroscopy of mechanical dissipation in micro-mechanical membranes
Andreas Jöckel, Matthew T. Rakher, Maria Korppi +4
We measure the frequency dependence of the mechanical quality factor (Q) of SiN membrane oscillators and observe a resonant variation of Q by more than two orders of magnitude. The…
Electromagnetically Induced Transparency and Optical Pumping in the Hyperfine Paschen-Back Regime
Roberto Mottola, Gianni Buser, Philipp Treutlein
We report spectroscopy experiments of rubidium vapor in a high magnetic field under conditions of electromagnetically induced transparency (EIT) and optical pumping. The 1.1 T stat…
Optical coherent feedback control of a mechanical oscillator
Maryse Ernzer, Manel Bosch Aguilera, Matteo Brunelli +5
Feedback is a powerful and ubiquitous technique both in classical and quantum system control. Its standard implementation relies on measuring the state of a system, processing the…
Terrestrial Very-Long-Baseline Atom Interferometry: Summary of the Second Workshop
Adam Abdalla, Mahiro Abe, Sven Abend +307
This summary of the second Terrestrial Very-Long-Baseline Atom Interferometry (TVLBAI) Workshop provides a comprehensive overview of our meeting held in London in April 2024, build…
Optical Memory in a Microfabricated Rubidium Vapor Cell
Roberto Mottola, Gianni Buser, Philipp Treutlein
Scalability presents a central platform challenge for the components of current quantum network implementations that can be addressed by microfabrication techniques. We demonstrate…
Mesoscopic quantum superpositions in bimodal Bose-Einstein condensates: decoherence and strategies to counteract it
Krzysztof Pawlowski, Matteo Fadel, Philipp Treutlein +2
We study theoretically the interaction-induced generation of mesoscopic coherent spin state superpositions (small cat states) from an initial coherent spin state in bimodal Bose-Ei…
Quantum Information Processing in Optical Lattices and Magnetic Microtraps
Philipp Treutlein, Tilo Steinmetz, Yves Colombe +9
We review our experiments on quantum information processing with neutral atoms in optical lattices and magnetic microtraps. Atoms in an optical lattice in the Mott insulator regime…
Sympathetic cooling of a membrane oscillator in a hybrid mechanical-atomic system
Andreas Jöckel, Aline Faber, Tobias Kampschulte +3
Sympathetic cooling with ultracold atoms and atomic ions enables ultralow temperatures in systems where direct laser or evaporative cooling is not possible. It has so far been limi…
Coherent manipulation of Bose-Einstein condensates with state-dependent microwave potentials on an atom chip
Pascal Boehi, Max F. Riedel, Johannes Hoffrogge +3
Entanglement-based technologies, such as quantum information processing, quantum simulations, and quantum-enhanced metrology, have the potential to revolutionise our way of computi…
Imaging of Relaxation Times and Microwave Field Strength in a Microfabricated Vapor Cell
Andrew Horsley, Guan-Xiang Du, Matthieu Pellaton +3
We present a new characterisation technique for atomic vapor cells, combining time-domain measurements with absorption imaging to obtain spatially resolved information on decay tim…
Squeezing light with optomechanical and spin-light quantum interfaces
Gian-Luca Schmid, Manel Bosch Aguilera, Chun Tat Ngai +6
We investigate squeezing of light through quantum-noise-limited interactions with two different material systems: an ultracold atomic spin ensemble and a micromechanical membrane.…
Effective Faraday interaction between light and nuclear spins of Helium-3 in its ground state: a semiclassical study
Matteo Fadel, Philipp Treutlein, Alice Sinatra
We derive the semiclassical evolution equations for a system consisting of helium-3 atoms in the metastable state interacting with a light field far-detuned from the $2^3S-2…
Simple microwave field imaging technique using hot atomic vapor cells
Pascal Böhi, Philipp Treutlein
We demonstrate a simple technique for microwave field imaging using alkali atoms in a vapor cell. The microwave field to be measured drives Rabi oscillations on atomic hyperfine tr…
Simple atomic quantum memory suitable for semiconductor quantum dot single photons
Janik Wolters, Gianni Buser, Andrew Horsley +5
Quantum memories matched to single photon sources will form an important cornerstone of future quantum network technology. We demonstrate such a memory in warm Rb vapor with on-dem…
Hybrid Mechanical Systems
Philipp Treutlein, Claudiu Genes, Klemens Hammerer +2
We discuss hybrid systems in which a mechanical oscillator is coupled to another (microscopic) quantum system, such as trapped atoms or ions, solid-state spin qubits, or supercondu…
Terrestrial Very-Long-Baseline Atom Interferometry: Workshop Summary
Sven Abend, Baptiste Allard, Iván Alonso +250
This document presents a summary of the 2023 Terrestrial Very-Long-Baseline Atom Interferometry Workshop hosted by CERN. The workshop brought together experts from around the world…
On-demand semiconductor source of 780 nm single photons with controlled temporal wave packets
Lucas Béguin, Jan-Philipp Jahn, Janik Wolters +8
We report on a fast, bandwidth-tunable single-photon source based on an epitaxial GaAs quantum dot. Exploiting spontaneous spin-flip Raman transitions, single photons at nm…
Coherence in Microchip Traps
Philipp Treutlein, Peter Hommelhoff, Tilo Steinmetz +2
We report the coherent manipulation of internal states of neutral atoms in a magnetic microchip trap. Coherence lifetimes exceeding 1 s are observed with atoms at distances of $5-1…
Single-Photon Storage in a Ground-State Vapor Cell Quantum Memory
Gianni Buser, Roberto Mottola, Björn Cotting +2
Interfaced single-photon sources and quantum memories for photons together form a foundational component of quantum technology. Achieving compatibility between heterogeneous, state…
Widefield Microwave Imaging in Alkali Vapor Cells with sub-100 um Resolution
Andrew Horsley, Guan-Xiang Du, Philipp Treutlein
We report on widefield microwave vector field imaging with sub um resolution using a microfabricated alkali vapor cell. The setup can additionally image dc magnetic fields, and can…
Imaging Microwave and DC Magnetic Fields in a Vapor-Cell Rb Atomic Clock
Christoph Affolderbach, Guan-Xiang Du, Thejesh Bandi +3
We report on the experimental measurement of the DC and microwave magnetic field distributions inside a recently-developed compact magnetron-type microwave cavity, mounted inside t…
Tomographic reconstruction of the Wigner function on the Bloch sphere
Roman Schmied, Philipp Treutlein
We present a filtered backprojection algorithm for reconstructing the Wigner function of a system of large angular momentum j from Stern-Gerlach-type measurements. Our method is ad…
Einstein-Podolsky-Rosen experiment with two Bose-Einstein condensates
Paolo Colciaghi, Yifan Li, Philipp Treutlein +1
In 1935, Einstein, Podolsky and Rosen (EPR) conceived a Gedankenexperiment which became a cornerstone of quantum technology and still challenges our understanding of reality and lo…
Spatial entanglement patterns and Einstein-Podolsky-Rosen steering in a Bose-Einstein condensate
Matteo Fadel, Tilman Zibold, Boris Décamps +1
Many-particle entanglement is a fundamental concept of quantum physics that still presents conceptual challenges. While spin-squeezed and other nonclassical states of atomic ensemb…
Sideband Rabi spectroscopy of finite-temperature trapped Bose gases
Baptiste Allard, Matteo Fadel, Roman Schmied +1
We use Rabi spectroscopy to explore the low-energy excitation spectrum of a finite-temperature Bose gas of rubidium atoms across the phase transition to a Bose-Einstein condensate…
Light-mediated strong coupling between a mechanical oscillator and atomic spins one meter apart
Thomas M. Karg, Baptiste Gouraud, Chun Tat Ngai +3
Engineering strong interactions between quantum systems is essential for many phenomena of quantum physics and technology. Typically, strong coupling relies on short-range forces o…
Large-Range Frequency Tuning of a Narrow-Linewidth Quantum Emitter
Liang Zhai, Matthias C. Löbl, Jan-Philipp Jahn +5
A hybrid system of a semiconductor quantum dot single photon source and a rubidium quantum memory represents a promising architecture for future photonic quantum repeaters. One of…
Broad Instantaneous Bandwidth Microwave Spectrum Analyzer with a Microfabricated Atomic Vapor Cell
Yongqi Shi, Thomas Ruster, Melvyn Ho +3
We report on broad instantaneous bandwidth microwave spectrum analysis with hot atoms in a microfabricated vapor cell in a large magnetic field gradient. The sen…
Bell Correlations in a Bose-Einstein Condensate
Roman Schmied, Jean-Daniel Bancal, Baptiste Allard +4
Characterizing many-body systems through the quantum correlations between their constituent particles is a major goal of quantum physics. Although entanglement is routinely observe…
An artificial Rb atom in a semiconductor with lifetime-limited linewidth
Jan-Philipp Jahn, Mathieu Munsch, Lucas Béguin +10
We report results important for the creation of a best-of-both-worlds quantum hybrid system consisting of a solid-state source of single photons and an atomic ensemble as quantum m…
Microwave device characterisation using a widefield diamond microscope
Andrew Horsley, Patrick Appel, Janik Wolters +4
Devices relying on microwave circuitry form a cornerstone of many classical and emerging quantum technologies. A capability to provide in-situ, noninvasive and direct imaging of th…
Spin squeezing in a bimodal condensate: spatial dynamics and particle losses
Yun Li, Philipp Treutlein, Jakob Reichel +1
We propose an analytical method to study the entangled spatial and spin dynamics of interacting bimodal Bose-Einstein condensates. We show that at particular times during the evolu…
An efficient, tunable, and robust source of narrow-band photon pairs at the Rb D1 line
Roberto Mottola, Gianni Buser, Chris Müller +6
We present an efficient and robust source of photons at the Rb D1-line (795 nm) with a narrow bandwidth of MHz. The source is based on non-degenerate, cavity-enh…
Optimal entanglement witnesses in a split spin-squeezed Bose-Einstein condensate
Enky Oudot, Jean-Daniel Bancal, Roman Schmied +2
How to detect quantum correlations in bi-partite scenarios using a split many-body system and collective measurements on each party? We address this question by deriving entangleme…
Realization of an optomechanical interface between ultracold atoms and a membrane
Stephan Camerer, Maria Korppi, Andreas Jöckel +3
We have realized a hybrid optomechanical system by coupling ultracold atoms to a micromechanical membrane. The atoms are trapped in an optical lattice, which is formed by retro-ref…
Fundamental limit of phase coherence in two-component Bose-Einstein condensates
Yifan Li, Krzysztof PawÅowski, Boris Décamps +4
We experimentally and theoretically study phase coherence in two-component Bose-Einstein condensates of atoms on an atom chip. Using Ramsey interferometry we measur…
Bose-Einstein condensate coupled to a nanomechanical resonator on an atom chip
Philipp Treutlein, David Hunger, Stephan Camerer +2
We theoretically study the coupling of Bose-Einstein condensed atoms to the mechanical oscillations of a nanoscale cantilever with a magnetic tip. This is an experimentally viable…
Cold Atoms in Space: Community Workshop Summary and Proposed Road-Map
Ivan Alonso, Cristiano Alpigiani, Brett Altschul +246
We summarize the discussions at a virtual Community Workshop on Cold Atoms in Space concerning the status of cold atom technologies, the prospective scientific and societal opportu…
Imaging of microwave fields using ultracold atoms
Pascal Boehi, Max F. Riedel, Theodor W. Haensch +1
We report a technique that uses clouds of ultracold atoms as sensitive, tunable, and non-invasive probes for microwave field imaging with micrometer spatial resolution. The microwa…
Multiparameter estimation with an array of entangled atomic sensors
Yifan Li, Lex Joosten, Youcef Baamara +4
In quantum metrology, entangled states of many-particle systems are investigated to enhance measurement precision of the most precise clocks and field sensors. While single-paramet…
Light-Mediated Collective Atomic Motion in an Optical Lattice Coupled to a Membrane
Aline Vochezer, Tobias Kampschulte, Klemens Hammerer +1
We observe effects of collective atomic motion in a one-dimensional optical lattice coupled to an optomechanical system. In this hybrid atom-optomechanical system, the lattice ligh…
Microwave potentials and optimal control for robust quantum gates on an atom chip
Philipp Treutlein, Theodor W. Hänsch, Jakob Reichel +3
We propose a two-qubit collisional phase gate that can be implemented with available atom chip technology, and present a detailed theoretical analysis of its performance. The gate…
Atom chip based generation of entanglement for quantum metrology
Max F. Riedel, Pascal Böhi, Yun Li +3
Atom chips provide a versatile `quantum laboratory on a microchip' for experiments with ultracold atomic gases. They have been used in experiments on diverse topics such as low-dim…
Frequency-Tunable Microwave Field Detection in an Atomic Vapor Cell
Andrew Horsley, Philipp Treutlein
We use an atomic vapor cell as a frequency tunable microwave field detector operating at frequencies from GHz to tens of GHz. We detect microwave magnetic fields from 2.3 GHz to 26…
Bell correlations in a many-body system with finite statistics
Sebastian Wagner, Roman Schmied, Matteo Fadel +3
A recent experiment reported the first violation of a Bell correlation witness in a many-body system [Science 352, 441 (2016)]. Following discussions in this paper, we address here…
Spin squeezing and EPR entanglement of two bimodal condensates in state-dependent potentials
Hadrien Kurkjian, Krzysztof Pawlowski, Philipp Treutlein +1
We propose and analyze a scheme to entangle the collective spin states of two spatially separated bimodal Bose-Einstein condensates. Using a four-mode approximation for the atomic…
Quantum computing implementations with neutral particles
Antonio Negretti, Philipp Treutlein, Tommaso Calarco
We review quantum information processing with cold neutral particles, that is, atoms or polar molecules. First, we analyze the best suited degrees of freedom of these particles for…