Randomized control of open quantum systems

The problem of open-loop dynamical control of generic open quantum systems is addressed. In particular, I focus on the task of effectively switching off environmental couplings responsible for unwanted decoherence and dissipation effects. After revisiting the standard framework for dynamical decoupling via deterministic controls, I describe a different approach whereby the controller intentionally acquires a random component. An explicit error bound on worst-case performance of stochastic decoupling is presented.Comment: 6 pages, no figure, requires IEEEtran LaTe

Herds and Coherds

The first aim of this thesis is to give a unified and self-contained treatment of a number of known results related to the theory of herds. This gives us the technical tools to deal with the second aim of our work which is to obtain some new results about herds and coherds in the pure categorical setting. A herd at this level is a pretorsor τ : Q → QPQ satisfying associativity and unitality properties with respect to a formal dual structure M = (A, B, P,Q, σᴬ, σᴮ) ...

Resolvent estimates for non-selfadjoint operators with double characteristics

We study resolvent estimates for non-selfadjoint semiclassical pseudodifferential operators with double characteristics. Assuming that the quadratic approximation along the double characteristics is elliptic, we obtain polynomial upper bounds on the resolvent in a suitable region inside the pseudospectrum.Comment: 38 pages. J. London Math. Soc., to appear. Published version may diffe

Challenges in computational lower bounds

We draw two incomplete, biased maps of challenges in computational complexity lower bounds

Comment on Breakup Densities of Hot Nuclei

In [1,2]the observed decrease in spectral peak energies of IMFs emitted from hot nuclei was interpreted in terms of a breakup density that decreased with increasing energy. Subsequently, Raduta et al. [3] performed MMM simulations that showed decreasing spectral peaks could be obtained at constant density. In this letter we examine this apparent inconsistency.Comment: 9 pages, 2 figures, 1 tabl

Social interaction of patients and personnel in a ward situation

Thesis (M.S.)--Boston Universit

Quantum Magnetism, Spin Waves, and Light

Both magnetic materials and light have always played a predominant role in information technologies, and continue to do so as we move into the realm of quantum technologies. In this course we review the basics of magnetism and quantum mechanics, before going into more advanced subjects. Magnetism is intrinsically quantum mechanical in nature, and magnetic ordering can only be explained by use of quantum theory. We will go over the interactions and the resulting Hamiltonian that governs magnetic phenomena, and discuss its elementary excitations, denominated magnons. After that we will study magneto-optical effects and derive the classical Faraday effect. We will then move on to the quantization of the electric field and the basics of optical cavities. This will allow us to understand a topic of current research denominated Cavity Optomagnonics. These notes were written as the accompanying material to the course I taught in the Summer Semester 2018 at the Friedrich-Alexander University in Erlangen. The course is intended for Master or advanced Bachelor students. Basic knowledge of quantum mechanics, electromagnetism, and solid state at the Bachelor level is assumed. Each section is followed by a couple of simple exercises which should serve as to "fill in the blanks" of what has been derived, plus specific references to bibliography, and a couple of check-points for the main concepts developed. The figures are pictures of the blackboard taken during the lecture.Comment: Class notes, revised version, typos corrected, figures adde

Gender Equality in Educational Achievement An East-West Comparison

Data on educational access show gender parity of pupils attending primary and secondary schools in transition countries. The aim of this analysis is to examine whether the gender balance in educational access translates also into gender equality in educational achievement. Besides a comparison of gender differences in mean achievement for transition and a benchmark group of OECD countries differences in boys’ and girls’ achievement distributions and determinants of gender inequality are examined. The reliability of results is increased by carrying out the analyses with three different educational achievement surveys: the Trends in International Maths and Science Study (TIMSS), the Programme of International Student Assessment (PISA) and the Programme of International Reading Literacy Study (PIRLS)