arXiv subjects

Bruno Eckmann

Publications and source records attributed to Bruno Eckmann.

3 recordsLinked to original sources

arXiv2024

Comparison of Impedance Matching Networks for Scanning Microwave Microscopy

In this paper, a definition of the gain and added noise of impedance matching networks for scanning microwave microscopy is given. This definition can be used to compare different impedance matching techniques independently of the instrument used to measure the S-parameter. As a demonstration, impedance matching devices consisting of a Beatty line, a tuner, and interferometric setups with and without amplifiers have been investigated. Measurement frequencies up to 28 GHz are used, and the maximal resulting gain found was 9504.7 per Siemens.

physics.ins-det↗

arXiv2020

Characterization of space-momentum entangled photon with a time resolving CMOS SPAD array

Single photon avalanche diode arrays can provide both the spatial and temporal information of each detected photon. We present here the characterization of entangled light with a sensor specifically designed for quantum imaging applications. The sensors is time-tagging each detection events at the pixel level with sub-nanosecond accuracy, within frames of 50 ns. The spatial correlations between any number of detections in a defined temporal window can thus be directly extracted from the data. We show the ability of the sensor to characterize space-momentum entangled photon pairs emitted by spontaneous parametric downconversion. Their entanglement is demonstrated by violating an EPR-type inequality.

quant-ph↗

arXiv2018

Preliminary investigation of a new state estimation technique using device-independent maximum likelihood estimation

In quantum state tomography, the estimated frequencies do not correspond directly to a physical quantum state, due to statistical fluctuations. Thus, one resorts to point estimators that return the state that matches observations the best, and a variety of estimators have been proposed -- linear inversion, least squares, maximum likelihood (ML) -- each making different trade-offs. In this short note, we investigate an alternative approach inspired by device-independent quantum information protocols. We embed a tomographic complete set of measurement operators within the framework of a Bell scenario, and first regularize the estimated frequencies using a device-independent maximum likelihood algorithm. We then run the standard maximum likelihood algorithm to estimate the underlying quantum state. In this preliminary investigation, we do not observe significant differences in the reconstructed state when using the new algorithm.

quant-ph↗