Publications (17)
Single-Photon Distillation via a Photonic Parity Measurement Using Cavity QED
Severin Daiss, Stephan Welte, Bastian Hacker +2
Single photons with tailored temporal profiles are a vital resource for future quantum networks. Here we distill them out of custom-shaped laser pulses that reflect from a single a…
High-NA vectorial hologram optimization
Michael Wischert, Fiona Hellstern, Paul Uerlings +3
We present a vectorial phase-only framework for the gradient-based optimization of computer-generated holograms. Our approach addresses a critical limitation in high numerical aper…
Deterministic creation of entangled atom-light Schrödinger-cat states
Bastian Hacker, Stephan Welte, Severin Daiss +4
Quantum physics allows for entanglement between microscopic and macroscopic objects, described by discrete and continuous variables, respectively. As in Schrödinger's famous cat g…
A photon-photon quantum gate based on a single atom in an optical resonator
Bastian Hacker, Stephan Welte, Gerhard Rempe +1
Two photons in free space pass each other undisturbed. This is ideal for the faithful transmission of information, but prohibits an interaction between the photons as required for…
Low-excitation transport and separation of high-mass-ratio mixed-species ion chains
Francesco Lancellotti, Stephan Welte, Matteo Simoni +6
We demonstrate low-excitation transport and separation of two-ion crystals consisting of one beryllium and one calcium ion, with a high mass ratio of . The full separation inv…
A quantum-network register assembled with optical tweezers in an optical cavity
Lukas Hartung, Matthias Seubert, Stephan Welte +2
Quantum computation and quantum communication are expected to provide users with capabilities inaccessible by classical physics. However, scalability to larger systems with many qu…
Cavity Carving of Atomic Bell States
Stephan Welte, Bastian Hacker, Severin Daiss +2
We demonstrate entanglement generation of two neutral atoms trapped inside an optical cavity. Entanglement is created from initially separable two-atom states through carving with…
A nondestructive Bell-state measurement on two distant atomic qubits
Stephan Welte, Philip Thomas, Lukas Hartung +5
One of the most fascinating aspects of quantum networks is their capability to distribute entanglement as a nonlocal communication resource. In a first step, this requires network-…
Error Correction of Beamsplitter-Generated Entangled GKP States
Moritz Fontboté-Schmidt, Jeremy Metzner, Florence Berterottière +8
To be useful, quantum computers will be required to successfully correct errors occurring at the hardware level. Bosonic codes provide a hardware-efficient option for error correct…
A Quantum-Logic Gate between Distant Quantum-Network Modules
Severin Daiss, Stefan Langenfeld, Stephan Welte +5
The big challenge in quantum computing is to realize scalable multi-qubit systems with cross-talk free addressability and efficient coupling of arbitrarily selected qubits. Quantum…
Quantum Teleportation between Remote Qubit Memories with Only a Single Photon as a Resource
Stefan Langenfeld, Stephan Welte, Lukas Hartung +5
Quantum teleportation enables the deterministic exchange of qubits via lossy channels. While it is commonly believed that unconditional teleportation requires a preshared entangled…
Detecting an Itinerant Optical Photon Twice without Destroying It
Emanuele Distante, Severin Daiss, Stefan Langenfeld +5
Nondestructive quantum measurements are central for quantum physics applications ranging from quantum sensing to quantum computing and quantum communication. Employing the toolbox…
Modular variable laser cooling for efficient entropy extraction
Brennan de Neeve, Thanh-Long Nguyen, Alexander Ferk +5
We propose and experimentally demonstrate a method for laser cooling an oscillator based on sequences of spin-state-dependent displacements followed by spin repumping. For a therma…
Two-qubit operations for finite-energy Gottesman-Kitaev-Preskill encodings
Ivan Rojkov, Paul Moser Röggla, Martin Wagener +4
We present techniques for performing two-qubit gates on Gottesman-Kitaev-Preskill (GKP) codes with finite energy, and find that operations designed for ideal infinite-energy codes…
Photon-Mediated Quantum Gate between Two Trapped Neutral Atoms in an Optical Cavity
Stephan Welte, Bastian Hacker, Severin Daiss +2
Quantum logic gates are fundamental building blocks of quantum computers. Their integration into quantum networks requires strong qubit coupling to network channels, as can be real…
Tweezer-assisted subwavelength positioning of atomic arrays in an optical cavity
Matthias Seubert, Lukas Hartung, Stephan Welte +2
We present an experimental technique that enables the preparation of defect-free arrays of 87Rb atoms within a microscopic high-finesse optical standing-wave cavity. By employing o…
Two-dimensional shelving spectroscopy of ultraviolet ground state transitions in dysprosium
Kevin S. H. Ng, Paul Uerlings, Fiona Hellstern +5
The open inner-shell electronic structure of lanthanides with large magnetic moments gives rise to a rich spectrum of transitions available for laser cooling, trapping, and coheren…