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Jeremy Metz

Publications and source records attributed to Jeremy Metz.

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Data acquisition from high-rate detectors at MAX IV

At MAX IV pixelated area detectors are operated at high frame rates to take advantage of the X-ray beam properties available from the fourth generation synchrotron in scattering, diffraction and imaging applications. A variety of photon counting and charge integrating detectors and sCMOS cameras have been integrated into a common data acquisition (DAQ) system in which data are streamed to a central Kubernetes cluster, mounting an IBM Storage Scale (GPFS) file system. The DAQ system provides live feedback from the detectors/cameras and extends to enable on-the-fly data processing. Control system integration via Tango provides a standardised single interface for controlling all DAQ components. Starting from an overview of the detector types in use, we describe the design and implementation of the MAX~IV detector-DAQ system and report a quantitative study of its performance in terms of data throughput and detector operating rates.

physics.ins-det

Deep learning guided image-based droplet sorting for on-demand selection and analysis of single cells and 3D cell cultures

Uncovering the heterogeneity of cell populations is a long-standing goal in fields ranging from antimicrobial resistance to cancer research. Emerging technology platforms such as droplet microfluidics hold the promise to decipher cellular heterogeneity at ultra-high-throughput. However, there is a lack of methods able to rapidly identify and isolate single cells or 3D cell cultures. Here we demonstrate that deep neural networks can accurately classify single droplet images in real-time based on the presence and number of micro-objects including single mammalian cells and multicellular spheroids. This approach also enables the identification of specific objects within mixtures of objects of different types and sizes. The training sets for the neural networks consisted of several hundred images manually picked and augmented to up to thousands of images per training class. Training required less than 10 minutes using a single GPU, and yielded accuracies of over 90% for single mammalian cell identification. Crucially, the same model could be used to classify different types of objects such as polystyrene spheres, polyacrylamide beads and MCF-7 cells. We applied the developed method to the selection of 3D cell cultures generated with Hek293FT cells encapsulated in agarose gel beads, highlighting the potential of the technology for the selection of objects with high diversity of visual appearance. The real-time sorting of single droplets was in-line with droplet generation and occurred at rates up to 40 per second independently of image size up to 480 x 480 pixels. The presented microfluidic device also enabled storage of sorted droplets to allow for downstream analyses.

eess.IV

Atomic cluster state build up with macroscopic heralding

We describe a measurement-based state preparation scheme for the efficient build up of cluster states in atom-cavity systems. As in a recent proposal for the generation of maximally entangled atom pairs [Metz et al., Phys. Rev. Lett. 97, 040503 (2006)], we use an electron shelving technique to avoid the necessity for the detection of single photons. Instead, the successful fusion of smaller into larger clusters is heralded by an easy-to-detect macroscopic fluorescence signal. High fidelities are achieved even in the vicinity of the bad cavity limit and are essentially independent of the concrete size of the system parameters.

quant-ph

Macroscopic quantum jumps and entangled state preparation

Recently we predicted a random blinking, i.e. macroscopic quantum jumps, in the fluorescence of a laser-driven atom-cavity system [Metz et al., Phys. Rev. Lett. 97, 040503 (2006)]. Here we analyse the dynamics underlying this effect in detail and show its robustness against parameter fluctuations. Whenever the fluorescence of the system stops, a macroscopic dark period occurs and the atoms are shelved in a maximally entangled ground state. The described setup can therefore be used for the controlled generation of entanglement. Finite photon detector efficiencies do not affect the success rate of the state preparation, which is triggered upon the observation of a macroscopic fluorescence signal. High fidelities can be achieved even in the vicinity of the bad cavity limit due to the inherent role of dissipation in the jump process.

quant-ph

Robust Entanglement through Macroscopic Quantum Jumps

We propose an entanglement generation scheme that requires neither the coherent evolution of a quantum system nor the detection of single photons. Instead, the desired state is heralded by a {\em macroscopic} quantum jump. Macroscopic quantum jumps manifest themselves as a random telegraph signal with long intervals of intense fluorescence (light periods) interrupted by the complete absence of photons (dark periods). Here we show that a system of two atoms trapped inside an optical cavity can be designed such that a dark period prepares the atoms in a maximally entangled ground state. Achieving fidelities above 0.9 is possible even when the single-atom cooperativity parameter C is as low as 10 and when using a photon detector with an efficiency as low as eta = 0.2.

quant-ph