S. Whitlock
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Quantum network tomography of Rydberg arrays by machine learning Open
Configurable arrays of optically trapped Rydberg atoms are a versatile platform for quantum computation and quantum simulation, also allowing controllable decoherence. We demonstrate theoretically, that they also enable proof-of-principle …
View article: Compact optical waveform generator with digital feedback
Compact optical waveform generator with digital feedback Open
A key requirement for quantum technologies based on atoms, ions, and molecules, is the ability to realize precise phase- and amplitude-controlled quantum operations via coherent laser pulses. However, for generating pulses on the sub-micro…
Automated quantum system modeling with machine learning Open
Despite the complexity of quantum systems in the real world, models with just a few effective many-body states often suffice to describe their quantum dynamics, provided decoherence is accounted for. We show that a machine learning algorit…
Bose-einstein condensates on a permanent magnetic film atom chip Open
We present a permanent magnetic film atom chip based on perpendicularly magnetized TbGdFeCo films. This chip routinely produces a Bose-Einstein condensate (BEC) of 10 5 87Rb atoms using the magnetic film potential. Fragmentation observed n…
Bose-Einstein condensates on magnetic film microstructures Open
We report on recent experiments with BECs and ultracold atoms in magnetic microtraps created by magnetic film microstructures on an atom chip. We describe the use of RF spectroscopy plus absorption imaging of ultracold atoms as a sensitive…
Bose-Einstein condensates on a magnetic film atom chip Open
Atom chips are devices used to magnetically trap and manipulate ultracold atoms and Bose-Einstein condensates near a surface. In particular, permanent magnetic film atom chips can allow very tight confinement and intricate magnetic field d…
A permanent magnetic film atom chip for Bose-Einstein condensation Open
We present a hybrid atom chip which combines a permanent magnetic film with a micromachined current-carrying structure used to realize a Bose-Einstein condensate (BEC). A novel TbGdFeCo material with large perpendicular magnetization has b…
View article: Fast and robust cat state preparation utilizing higher order nonlinearities
Fast and robust cat state preparation utilizing higher order nonlinearities Open
Cat states are a valuable resource for quantum metrology applications, promising to enable sensitivity down to the Heisenberg limit. Moreover, Schrödinger cat states, based on a coherent superposition of coherent states, show robustness ag…
Quantum Factoring Algorithm using Grover Search Open
We present a quantum algorithm for factoring products of prime numbers which exploits Grover search to factor any $n$-bit biprime using $2n-5$ qubits or less. The algorithm doesn't depend on any properties of the number to be factored, has…
Robust phase-controlled gates for scalable atomic quantum processors using optical standing waves Open
A simple scheme is presented for realizing robust optically controlled quantum gates for scalable atomic quantum processors by driving the qubits with optical standing waves. Atoms localized close to the antinodes of the standing wave can …
Robust phase-controlled gates for scalable atomic quantum processors using optical standing waves Open
A simple scheme is presented for realizing robust optically controlled quantum gates for scalable atomic quantum processors by driving the qubits with optical standing waves. Atoms localized close to the antinodes of the standing wave can …
Hydrodynamic Stabilization of Self-Organized Criticality in a Driven Rydberg Gas Open
Signatures of self-organized criticality (SOC) have recently been observed in an ultracold atomic gas under continuous laser excitation to strongly interacting Rydberg states [S. Helmrich et al., Nature, 577, 481-486 (2020)]. This creates …
Quantum simulation and computing with Rydberg qubits Open
Arrays of optically trapped atoms excited to Rydberg states have recently emerged as a competitive physical platform for quantum simulation and computing, where high-fidelity state preparation and readout, quantum logic gates and controlle…
View article: Collective Dissipative Molecule Formation in a Cavity
Collective Dissipative Molecule Formation in a Cavity Open
We propose a mechanism to realize high-yield molecular formation from ultracold atoms. Atom pairs are continuously excited by a laser, and a collective decay into the molecular ground state is induced by a coupling to a lossy cavity mode. …
Two-dimensional spectroscopy of Rydberg gases Open
Two-dimensional (2D) spectroscopy uses multiple electromagnetic pulses to infer the properties of a complex system. A paradigmatic class of target systems are molecular aggregates, for which one can obtain information on the eigenstates, v…
Unitary and Nonunitary Quantum Cellular Automata with Rydberg Arrays Open
We propose a physical realization of quantum cellular automata (QCA) using arrays of ultracold atoms excited to Rydberg states. The key ingredient is the use of programmable multifrequency couplings which generalize the Rydberg blockade an…
Trapping ultracold atoms in submicron period magnetic lattices Open
Periodic arrays of magnetic microtraps patterned on a magnetic film provide a potential complementary tool to conventional optical lattices for trapping ultracold atoms. Dr. Tran’s thesis presents the trapping of Rubidium atoms in submicro…
View article: Diffusive to Nonergodic Dipolar Transport in a Dissipative Atomic Medium
Diffusive to Nonergodic Dipolar Transport in a Dissipative Atomic Medium Open
We investigate the dipole-mediated transport of Rydberg impurities through an ultracold gas of atoms prepared in an auxiliary Rydberg state. In one experiment, we continuously probe the system by coupling the auxiliary Rydberg state to a r…
Magnetic lattices for ultracold atoms Open
This article reviews the development in our laboratory of magnetic lattices comprising periodic arrays of magnetic microtraps created by patterned magnetic films to trap periodic arrays of ultracold atoms. Recent achievements include the r…
Magnetic Lattices for Ultracold Atoms Open
This article reviews the development in our laboratory of magnetic lattices comprising periodic arrays of magnetic microtraps created by patterned magnetic films to trap periodic arrays of ultracold atoms. Recent achievements include the r…
Realization of a Rydberg-Dressed Ramsey Interferometer and Electrometer Open
We present the experimental realization and characterization of a Ramsey interferometer based on optically trapped ultracold potassium atoms, where one state is continuously coupled by an off-resonant laser field to a highly excited Rydber…
Realization of a Rydberg-dressed atomic clock. Open
We present the experimental realization and characterization of an atomic clock based on optically trapped ultracold potassium atoms, where one state is continuously coupled by an off-resonant laser field to a highly-excited Rydberg state.…
Uncovering the nonequilibrium phase structure of an open quantum spin system Open
We experimentally and theoretically investigate the non-equilibrium phase structure of a well-controlled driven-disspative quantum spin system governed by the interplay of coherent driving, spontaneous decay and long-range spin-spin intera…
Observation of Self-Organised Criticality in an Ultracold Atomic Gas Open
Self organisation provides an elegant explanation for how complex structures emerge and persist throughout nature. Surprisingly often, these structures exhibit remarkably similar scale-invariant properties. While this is sometimes captured…
Relaxation of an Isolated Dipolar-Interacting Rydberg Quantum Spin System Open
How do isolated quantum systems approach an equilibrium state? We experimentally and theoretically address this question for a prototypical spin system formed by ultracold atoms prepared in two Rydberg states with different orbital angular…
Versatile, high-power 460 nm laser system for Rydberg excitation of ultracold potassium Open
We present a versatile laser system which provides more than 1.5 W of narrowband light, tunable in the range from 455-463 nm. It consists of a commercial titanium-sapphire laser which is frequency doubled using resonant cavity second harmo…
Simulating quantum spin models using Rydberg-excited atomic ensembles in magnetic microtrap arrays Open
We propose a scheme to simulate lattice spin models based on strong and long-range interacting\nRydberg atoms stored in a large-spacing array of magnetic microtraps. Each spin is encoded in\na collective spin state involving a single nP Ry…