Octave-tunable miniature RF resonators

The development and testing of a miniaturized, high-Q, broadly tunable resonator is described. An exemplary device, with a center frequency that is continuously tunable from 1.2 to 2.6 GHz, was tested in detail. Experimental results demonstrated a resonator Q of up to 380, and typical insertion loss of -1.9 dB for a 25 MHz 3-dB bandwidth. These resonators have been used to stabilize a broadly-tunable oscillator with phase noise of -132 dBc/Hz at 100-kHz offset, with a center frequency tunable from 1.2-2.6 GHz, and a tuning speed of 1 GHz/ms

The Consumption of Reference Resources

Under the operational restriction of the U(1)-superselection rule, states that contain coherences between eigenstates of particle number constitute a resource. Such resources can be used to facilitate operations upon systems that otherwise cannot be performed. However, the process of doing this consumes reference resources. We show this explicitly for an example of a unitary operation that is forbidden by the U(1)-superselection rule.Comment: 4 pages 6x9 page format, 2 figure

On the reliability of initial conditions for dissipationless cosmological simulations

We present the study of ten random realizations of a density field characterized by a cosmological power spectrum P(k) at redshift z=50. The reliability of such initial conditions for n-body simulations are tested with respect to their correlation properties. The power spectrum P(k), and the mass variance sigmaM(r) do not show detectable deviations from the desired behavior in the intermediate range of scales between the mean interparticle distance and the simulation volume. The estimator for xi(r) is too noisy to detect any reliable signal at the initial redshift z=50. The particle distributions are then evolved forward until z=0. This allows us to explore the cosmic variance stemming from the random nature of the initial conditions. With cosmic variance we mean the fact that a simulation represents a single realization of the stochastic initial conditions whereas the real Universe contains many realizations of regions of the size of the box; this problem affects most importantly the scales at about the fundamental mode. We study morphological descriptors of the matter distribution such as the genus, as well as the internal properties of the largest object(s) forming in the box. We find that the scatter is at least comparable to the scatter in the fundamental mode.Comment: 22 pages, 12 figures, replaced with major revision to previous submission, PASA in pres

Surveillance law, data retention and risks to democracy and rights

In Klass and others v Germany, the first surveillance case before the European Court of Human Rights, it was acknowledged that the threat of secret surveillance posed by highlighting its awareness ‘of the danger such a law poses of undermining or even destroying democracy on the ground of defending it.’ This thesis considers a form of surveillance, communications data retention as envisioned in Part 4 of the Investigatory Powers Act 2016 and its compatibility with the European Convention on Human Rights. This thesis highlights that communications data is not only just as, if not more intrusive than intercepting content based on what can be retained. It also reveals that communications data is mass surveillance within surveillance. Additionally, this thesis demonstrates that communications data does not just interference Article 8 of the Convention, but a collection of Convention Rights including Articles 9, 10, 11, 14, Article 2 Protocol 4 and potentially Article 6. Each of these rights are important for democracy and Article 8 and privacy underpins them all. Furthermore, this thesis highlights that obligation to retain communications data can be served on anything that can communicate across any network. Taking all factors highlighted into consideration, when assessed for compatibility with the Convention, communications data retention in Part 4 not only fails to be ‘in accordance with the law’, it fails to establish a legitimate aim, and fails to demonstrate its necessity and proportionality. In establishing that communications data retention as envisaged in Part 4 of the Investigatory Powers Act 2016 is incompatible with the Convention, it demonstrates that it undermines democracy and has sown the seeds for its destruction. Not only would the findings of this thesis create an obstacle to an UK-EU post- Brexit adequacy finding, it would have an impact beyond UK law as many States in Europe and outside seek to cement data retention nationally