arXiv subjects

Mónica B. Agüero

Publications and source records attributed to Mónica B. Agüero.

3 recordsLinked to original sources

arXiv2018

Addendum to: Kolmogorov complexity of sequences of random numbers generated in Bell's experiments (series of outcomes)

In the mentioned paper we presented results of the estimation of Kolmogorov complexity of sequences of random numbers generated in a famous Bell's experiment, aimed to study the security of QKD. We focused on series of time differences between successive detections of coincidences, and found that randomness cannot be taken for granted. It was then criticized that the theorems that demonstrate the randomness of series produced in Bell's experiments involve series of measurement outcomes, not of measurement times. Here we reply to this objection and present data of series of outcomes, showing that the conclusions in the mentioned paper are valid also in this case.

quant-ph↗

arXiv2018

Kolmogorov complexity of sequences of random numbers generated in Bell's experiments

Quantum systems are the ultimate touchstone for the production of random sequences of numbers. Spatially spread entangled systems allow the generation of identical random sequences in remote locations. The impossibility of observing a quantum system, without disturbing it, ensures that the messages encoded using these sequences cannot be eavesdropped. This is the basis of Quantum Key Distribution. It is then of crucial importance knowing whether the sequences generated in the practice by spatially spread entangled states are truly random, or not. Yet, that knowledge is not immediate. One of the obstacles is the very definition of randomness. Statistical randomness is related with the frequency of occurrence of strings of data. On the other hand, algorithmic randomness is related with the compressibility of the sequence, what is given by Kolmogorov complexity. We analyze sequences generated by entangled pairs of photons focusing on an estimation of their complexity.

quant-ph↗

arXiv2013

Measuring entanglement of photons produced by a pulsed source

A pulsed source of entangled photons is desirable for some applications. Yet, such a source has intrinsic problems arising from the simultaneous arrival of the signal and noise photons to the detectors. These problems are analyzed and practical methods to calculate the number of accidental (or spurious) coincidences are described in detail, and experimentally checked, for the different regimes of interest. The results are useful not only to measure entanglement, but to all the situations where extracting the number of valid coincidences from noisy data is required. As an example of the use of those methods, we present the time-resolved measurement of the Concurrence of the field produced by spontaneous parametric down conversion with pump pulses of duration in the ns-range at a repetition of kHz. The predicted discontinuous evolution of the entanglement at the edges of the pump pulse is observed.

physics.optics↗