The Gamow-Teller Resonance in Finite Nuclei in the Relativistic Random Phase Approximation

Gamow-Teller(GT) resonances in finite nuclei are studied in a fully consistent relativistic random phase approximation (RPA) framework. A relativistic form of the Landau-Migdal contact interaction in the spin-isospin channel is adopted. This choice ensures that the GT excitation energy in nuclear matter is correctly reproduced in the non-relativistic limit. The GT response functions of doubly magic nuclei $^{48}$Ca, $^{90}$Zr and $^{208}$Pb are calculated using the parameter set NL3 and $g_0'$=0.6 . It is found that effects related to Dirac sea states account for a reduction of 6-7 % in the GT sum rule.Comment: 9 pages, 1 figur

Interdimensional degeneracies for a quantum NN-body system in DD dimensions

Complete spectrum of exact interdimensional degeneracies for a quantum $N$-body system in $D$-dimensions is presented by the method of generalized spherical harmonic polynomials. In an $N$-body system all the states with angular momentum $[\mu+n]$ in $(D-2n)$ dimensions are degenerate where $[\mu]$ and $D$ are given and $n$ is an arbitrary integer if the representation $[\mu+n]$ exists for the SO($D-2n$) group and $D-2n\geq N$. There is an exceptional interdimensional degeneracy for an $N$-body system between the state with zero angular momentum in $D=N-1$ dimensions and the state with zero angular momentum in $D=N+1$ dimensions.Comment: 8 pages, no figure, RevTex, Accepted by EuroPhys.Let

Charge-to-spin conversion of electron entanglement states and spin-interaction-free solid-state quantum computation

Without resorting to spin-spin coupling, we propose a scalable spin quantum computing scheme assisted with a semiconductor multiple-quantum-dot structure. The techniques of single electron transitions and the nanostructure of quantum-dot cellular automata (QCA) are used to generate charge entangled states of two electrons, which are then converted into spin entanglement states using single-spin rotations only. Deterministic two-qubit quantum gates are also manipulated using only single-spin rotations with the help of QCA. A single-shot readout of spin states can be carried out by coupling the multiple dot structure to a quantum point contact. As a result, deterministic spin-interaction-free quantum computing can be implemented in semiconductor nanostructure.Comment: 5 pages, 4 figures, the revised version of quant-ph/0502002 for publication in Phys. Rev. B (to be appear on the issue of Oct. 15, 2007

Explainable Contextual Anomaly Detection using Quantile Regression Forests

Traditional anomaly detection methods aim to identify objects that deviate from most other objects by treating all features equally. In contrast, contextual anomaly detection methods aim to detect objects that deviate from other objects within a context of similar objects by dividing the features into contextual features and behavioral features. In this paper, we develop connections between dependency-based traditional anomaly detection methods and contextual anomaly detection methods. Based on resulting insights, we propose a novel approach to inherently interpretable contextual anomaly detection that uses Quantile Regression Forests to model dependencies between features. Extensive experiments on various synthetic and real-world datasets demonstrate that our method outperforms state-of-the-art anomaly detection methods in identifying contextual anomalies in terms of accuracy and interpretability.Comment: Manuscript submitted to Data Mining and Knowledge Discovery in October 2022 for possible publication. This is the revised version submitted in April 202

New insight in the Hawaiian plume swell dynamics from scaling laws

The formation and shape variation of the Hawaiian plume swell is re-examined numerically. Scaling laws for the plume buoyancy flux and swell width and height help gaining new insight in relationships between swell formation and relevant model parameters, like plume temperature and size, and mantle rheology. A scaling law for the plume buoyancy F = Aη0 −1.2 R p 3.5ΔT p 2.2 exp(1.3 × 10−8 EΔT p ), with background mantle viscosity η0, plume radius R p , plume excess temperature ΔT p , and activation energy E fits numerical flux measurements within 8%. Scaling laws for the swell width and height have similar forms, and their multiplication resembles the buoyancy flux scaling law within 10%. These scaling laws suggest that the background mantle viscosity plays a significant role, and that the increased Hawaiian plume intensity ∼25 Ma ago is due to a plume excess temperature increase of 50%

Franck-Condon Blockade in a Single-Molecule Transistor

We investigate vibron-assisted electron transport in single-molecule transistors containing an individual Fe4 Single-Molecule Magnet. We observe a strong suppression of the tunneling current at low bias in combination with vibron-assisted excitations. The observed features are explained by a strong electron-vibron coupling in the framework of the Franck-Condon model supported by density-functional theory