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We study the competition between two different topological orders in three dimensions by considering the X-cube model and the three-dimensional toric code. The corresponding Hamiltonian can be decomposed into two commuting parts, one of which displays a self-dual spectrum. To determine the phase diagram, we compute the high-order series expansions of the ground-state energy in all limiting cases. Apart from the topological order related to the toric code and the fractonic order related to the X-cube model, we found two new phases which are adiabatically connected to classical limits with nontrivial sub-extensive degeneracies. All phase transitions are found to be first order.

Heller et al.(2013) state that in multiple sclerosis patients, inversion of the foot at terminal swing is insufficiently corrected. However, it is the inversion of the foot at the end of the stance phase that is insufficiently corrected because of poor eversion of the foot in the early swing phase, which results in early ground contact of the outside border of the still partially inverted foot in the terminal swing phase. In minimally impaired multiple sclerosis patients walking on a treadmill, this leads to the producing of characteristic high-pitched shuffling sounds, generated in fact by a temporary friction of the outside border of the shod foot-in-terminal-swing, along the surface of the treadmill belt. Scientific Contract Research by K. J. van Zwieten, at the University of Hasselt, Belgium : "Foot inversion and eversion movements in stance and swing - some comparative-anatomical and functional morphological aspects (R-3500)", 1-01-2012 - 31-12-2013.

The so-called singer’s formant is a merge between at least two formants, possibly F3 and F4. We reconstructed some functional-anatomical phenomena in pronouncing the vowel /i/, by means of a crossed four-bar-linkage model simulating jaw motion in a sagittal plane. During uttering the high front vowel /i/ in “Heed”, the tongue’s dorsum is lifted, so as to narrow the linguo-palatal port, while the velo-pharyngeal port simultaneously closes. Although Sundberg et al. (2007) presume individual preference in the amount of this velo-pharyngeal closing during the production of a singer’s formant, we rather interpret this as a tautening of the palatine aponeurosis by bilateral activity of the tensor veli palatini muscle, neuromotorically associated with a slight elevation of the mandible by bilateral activity of a.o. the medial pterygoid muscle. Endorsed by the City of Tongeren, Belgium.

The challenge of one-dimensional systems is to understand their physics beyond the level of known elementary excitations. By high-resolution neutron spectroscopy in a quantum spin ladder material, we probe the leading multiparticle excitation by characterizing the two-magnon bound state at zero field. By applying high magnetic fields, we create and select the singlet (longitudinal) and triplet (transverse) excitations of the fully spin-polarized ladder, which have not been observed previously and are close analogs of the modes anticipated in a polarized Haldane chain. Theoretical modelling of the dynamical response demonstrates our complete quantitative understanding of these states.