Search results for "HLM"
showing 9 items of 9 documents
Six-parameters deformations of fourth order Peregrine breather solutions of the NLS equation.
2013
We construct solutions of the focusing NLS equation as a quotient of two determinants. This formulation gives in the case of the order 4, new deformations of the Peregrine breather with 6 real parameters. We construct families of quasi-rational solutions of the NLS equation and describe the apparition of multi rogue waves. With this method, we construct the analytical expressions of deformations of the Peregrine breather of order 4 with 6 real parameters and plot different types of rogue waves.
On Ignoring the Random Effects Assumption in Multilevel Models: Review, Critique, and Recommendations
2019
Entities such as individuals, teams, or organizations can vary systematically from one another. Researchers typically model such data using multilevel models, assuming that the random effects are uncorrelated with the regressors. Violating this testable assumption, which is often ignored, creates an endogeneity problem thus preventing causal interpretations. Focusing on two-level models, we explain how researchers can avoid this problem by including cluster means of the Level 1 explanatory variables as controls; we explain this point conceptually and with a large-scale simulation. We further show why the common practice of centering the predictor variables is mostly unnecessary. Moreover, …
'Ruhm' di Daniel Kehlmann: tra realtà e dimensione virtuale
2020
The essay analyzes Ruhm of Daniel Kehlmann. Focus is the use of mass media in everyday life and the relationship that individuals have with modern technology. Central point is also the phenomenon of identity duplication caused by the abuse of the mass media
Uhlmann curvature in dissipative phase transitions
2018
We study the mean Uhlmann curvature in fermionic systems undergoing a dissipative driven phase transition. We consider a paradigmatic class of lattice fermion systems in non-equilibrium steady-state of an open system with local reservoirs, which are characterised by a Gaussian fermionic steady state. In the thermodynamical limit, in systems with translational invariance we show that a singular behaviour of the Uhlmann curvature represents a sufficient criterion for criticalities, in the sense of diverging correlation length, and it is not otherwise sensitive to the closure of the Liouvillian dissipative gap. In finite size systems, we show that the scaling behaviour of the mean Uhlmann curv…
Uhlmann number in translational invariant systems
2019
We define the Uhlmann number as an extension of the Chern number, and we use this quantity to describe the topology of 2D translational invariant Fermionic systems at finite temperature. We consider two paradigmatic systems and we study the changes in their topology through the Uhlmann number. Through the linear response theory we linked two geometrical quantities of the system, the mean Uhlmann curvature and the Uhlmann number, to directly measurable physical quantities, i.e. the dynamical susceptibility and to the dynamical conductivity, respectively.
1970-luku : uudenlainen poliittisuus
2017
Paikantuneita haluja : seksuaalisuus ja tila Christer Kihlmanin tuotannossa
2014
Homoseksuaalisuuden ja seksuaalisen toiseuden kuvaukset ovat olleet suomalaisessa kirjallisuudessa pitkään kartoittamaton alue. Identiteettipoliittisen ulostulokirjallisuuden perinteen puuttuminen ei ole kuitenkaan estänyt käsittelemästä aihetta. Mikko Carlsonin tutkimus suomenruotsalaisen kirjailijan Christer Kihlmanin tuotannosta pureutuu 1970- ja 1980-luvuilla julkaistuihin teoksiin, joiden ilmestyminen osui kiinnostavaan seksuaalipoliittiseen murroskohtaan. Millä tavoin normeja rikkova seksuaalisuus suhteutuu kulttuuriseen tilaan? Miten Kihlmanin teokset murtavat seksuaalista kahtiajakoa? Mitä ovat kaapista ulostulon erityiset kulttuuriset reunaehdot, kun suomenruotsalainen kulttuuri va…
An informal procedure to detect outliers in multilevel models
2008
Finite-temperature geometric properties of the Kitaev honeycomb model
2018
We study finite temperature topological phase transitions of the Kitaev's spin honeycomb model in the vortex-free sector with the use of the recently introduced mean Uhlmann curvature. We employ an appropriate Fermionisation procedure to study the system as a two-band p-wave superconductor described by a BdG Hamiltonian. This allows to study relevant quantities such as Berry and mean Uhlmann curvatures in a simple setting. More specifically, we consider the spin honeycomb in the presence of an external magnetic field breaking time reversal symmetry. The introduction of such an external perturbation opens a gap in the phase of the system characterised by non-Abelian statistics, and makes the…