Scientific Highlights
Global Sensitivity Analysis and Registration Strategy for Temperature Profiles of Reflood Experiment Simulations
Global sensitivity analysis (GSA) is routinely applied in engineering to determine the sensitivity of a simulation output to the input parameters. Typically, GSA methods require the code output to be a scalar. In the context of thermal-hydraulic system code, however, simulation outputs are often not scalar but time-dependent (e.g. temperature profile). How to perform GSA on these outputs?
A new paper by Vitaly Sushkevich and Dennis Palagin is accepted to Angewandte Chemie
A new paper by Vitaly Sushkevich and Dennis Palagin is accepted to Angewandte ChemieNew issue of Angewandte Chemie is featuring a paper entitled "Effect of Active Sites Structure on Activity of Copper Mordenite in Aerobic and Anaerobic Conversion of Methane to Methanol" by Vitaly and Dennis.
A theory for the gapless field-induced quantum spin-liquid phase of α−RuCl3
The material α−RuCl3 continues to garner attention as the current poster child for realising the Kitaev model. New work places recent experimental observations on a solid theoretical footing, and concludes that the physics of α−RuCl3 is not dominated by Kitaev interactions.
Fresnel Zone Plates with Zone Widths below 10 nm
The spot size of a Fresnel Zone Plate lens is mainly determined by the zone widths of its outermost zone. It is therefore essential to fabricate zone plates with structures as small as possible for high-resolution X-ray microscopy. Researchers at the Laboratory for Micro- and Nanotechnology at the PSI have now developed Fresnel zone plates with zone widths well below 10 nm, down to 6.4 nm. These lenses are capable of pushing resolution in X-ray microscopy to the single-digit regime.
Topological quantum phase transition in the Ising-like antiferromagnetic spin chain BaCo2V2O8
Since the seminal ideas of Berezinskii, Kosterlitz and Thouless, topological excitations have been at the heart of our understanding of a whole novel class of phase transitions. In most cases, those transitions are controlled by a single type of topological objects. There are, however, some situations, still poorly understood, where two dual topological excitations fight to control the phase diagram and the transition.
Observation of two types of fractional excitation in the Kitaev honeycomb magnet
Quantum spin liquid is a disordered but highly entangled magnetic state with fractional spin excitations. The ground state of an exactly solved Kitaev honeycomb model is perhaps its clearest example. Under a magnetic field, a spin flip in this model fractionalizes into two types of anyon, a quasiparticle with more complex exchange statistics than standard fermions or bosons: a pair of gauge fluxes and a Majorana fermion.
Searching for New Physics with b → sτ+τ-
In recent years, intriguing hints for the violation of lepton flavor universality (LFU) have been accumulated in semileptonic B decays, both in the charged-current transitions b → cl-ν-l (i.e., RD, RD∗, and RJ/Ψ and the neutral-current transitions b → sl+l- (i.e., RK and RK∗.
Spin ice goes quantum
Numerous intriguing behaviours have been observed already in magnetic materials known as spin ices. But now for the first time direct manifestations of quantum mechanical effects have been seen in such a system.
Dirac and Chiral Quantum Spin Liquids on the Honeycomb Lattice in a Magnetic Field
Motivated by recent experimental observations in α-RuCl3, we study the Κ-Γ model on the honeycomb lattice in an external magnetic field. By a slave-particle representation and variational Monte Carlo calculations, we reproduce the phase transition from zigzag magnetic order to a field-induced disordered phase. The nature of this state depends crucially on the field orientation.
Experimental signatures of emergent quantum electrodynamics in Pr2Hf2O7
In a quantum spin liquid, the magnetic moments of the constituent electron spins evade classical long-range order to form an exotic state that is quantum entangled and coherent over macroscopic length scales. Such phases offer promising perspectives for device applications in quantum information technologies, and their study can reveal new physics in quantum matter.