In this paper a new method of distinguishing shower-like from track-like neutrino interaction events using event reconstruction data is introduced. This method is then used to minimise the error...Show moreIn this paper a new method of distinguishing shower-like from track-like neutrino interaction events using event reconstruction data is introduced. This method is then used to minimise the error that a shower-like event is misidenti ed as a track-like event and vice versa, which is necessary for measuring the neutrino mass hierarchy in ORCA. In its current format, the method leads to errors of around 0.40 for noisy simulation data and approximately 0.15 for noiseless data. However, the method can still be extended to take into account more information of the reconstructions, thereby possibly improving the results.Show less
This report presents a first attempt to introduce noise into the protocol of reference-frame- independent quantum key distribution. It is found that a frequently accepted manner to introduce noise,...Show moreThis report presents a first attempt to introduce noise into the protocol of reference-frame- independent quantum key distribution. It is found that a frequently accepted manner to introduce noise, according to the model of Eckert et al. proposed in ref. [1] leads to non-physical state matrices and therefore another model is proposed: the $\beta_{\pi}$-noise model. In this model the basis states composing the state matrix are perturbed by a complex quantity. For pure states this approach is applied to all state matrix elements, whereas for mixed states it is applied only to the diagonal elements. The off-diagonal elements in the mixed state are perturbed by a complex quantity that is independent of the perturbations on the basis states that the matrix element consists of. Using a Monte Carlo simulation, statistics on the quantum bit error rate as well as the transverse correlation factor are obtained for this model. However, although the $\beta_{\pi}$-noise model solves the main issues that lead to the conclusion that the model of Eckert et al. might infer non-physical state matrices, it does not yet guarantee the state matrix is always physical: a mixed state may still violate positive semi-definiteness. Therefore the original model is improved by perturbing all basis states as before and using this approach for all state matrix elements. In this improved version of the $\beta_{\pi}$-noise model Eve is present as a (complex) scaling of the off-diagonal state matrix elements. Thus, positive semi-definiteness is guaranteed for this noise model. Also for this improved version of the model statistics on the quantum bit error rate and the transverse correlation factor are presented, thereby describing the implications on an experiment.Show less
In this proposal an experiment is envisioned that is principally able to determine whether there exists a fundamental transition between quantum mechanics (QM) and classical mechanics (CM). In the...Show moreIn this proposal an experiment is envisioned that is principally able to determine whether there exists a fundamental transition between quantum mechanics (QM) and classical mechanics (CM). In the quantum realm spatial superpositions of a particle may exist, whereas these superpositions are not observed in the classical world. Many theories have been put forward to explain this difference. Of these, decoherence theories state that there is no explicit difference between QM and CM, but that quantum phenomena are extinguished upon increasing the coupling of the studied object to its environment. Other theories, however, predict that there is a fundamental scale - apart from the environmental coupling - at which spontaneous collapse of a superposition occurs. To test whether such a scale exists, it is proposed to build an interferometer that has a tuneable, coherent amplifier in each of its two arms. The interferometer is fed by a microwave single photon source that yields an entangled superposition of zero and one photon in the arms. The advantage of using microwave photons in a transmission line is that these are carried by electrons, which have a rest mass. Therefore, spontaneous collapse may be expected upon amplifying the superposition of the single photon to such an extent, that the QM-CM transition scale is exceeded. This set-up circumvents the limitation of contemporary experiments that study superpositions of objects fixed in size. By tuning the amplifiers one is now able to smoothly vary the size of the superposition, so that studying the transition scale and its nature becomes experimentally feasible. After introducing the theoretical ideas and the experimental status of the topic, this proposal elaborates on the research goal of the proposed experiment. Then, the method is presented including the experiment's preliminary design options and considerations as well as research steps and risks. Furthermore, the proposal includes a four-year plan of work, discusses the facilities and resources of the host group and stresses collaborations with both theorists and experimentalists.Show less
