1,326 research outputs found
Bohr's 1913 molecular model revisited
It is generally believed that the old quantum theory, as presented by Niels
Bohr in 1913, fails when applied to few electron systems, such as the H2
molecule. Here we find new solutions within the Bohr theory that describe the
potential energy curve for the lowest singlet and triplet states of H2 about as
well as the early wave mechanical treatment of Heitler and London. We also
develop a new interpolation scheme which substantially improves the agreement
with the exact ground state potential curve of H2 and provides a good
description of more complicated molecules such as LiH, Li2, BeH and He2.Comment: 6 pages, 9 figure
Direct social perception and dual process theories of mindreading
The direct social perception thesis claims that we can directly perceive some mental states of other people. The direct perception of mental states has been formulated phenomenologically and psychologically, and typically restricted to the mental state types of intentions and emotions. I will compare DSP to another account of mindreading: dual process accounts that posit a fast, automatic “Type 1” form of mindreading and a slow, effortful “Type 2” form. I will here analyze whether dual process accounts’ Type 1 mindreading serves as a rival to DSP or whether some Type 1 mindreading can be perceptual. I will focus on Apperly and Butterfill’s dual process account of mindreading epistemic states such as perception, knowledge, and belief. This account posits a minimal form of Type 1 mindreading of belief-like states called registrations. I will argue that general dual process theories fit well with a modular view of perception that is considered a kind of Type 1 process. I will show that this modular view of perception challenges and has significant advantages over DSP’s phenomenological and psychological theses. Finally, I will argue that if such a modular view of perception is accepted, there is significant reason for thinking Type 1 mindreading of belief-like states is perceptual in nature. This would mean extending the scope of DSP to at least one type of epistemic state
Colossal Spin Hall Effect in Ultrathin Metallic Films
We predict spin Hall angles up to 80% for ultrathin noble metal films with
substitutional Bi impurities. The colossal spin Hall effect is caused by
enhancement of the spin Hall conductivity in reduced sample dimension and a
strong reduction of the charge conductivity by resonant impurity scattering.
These findings can be exploited to create materials with high efficiency of
charge to spin current conversion by strain engineering.Comment: 4 pages, 5 figure
Investments in the beautiful game - the effect of ownership types on the performance of European football clubs - an empirical analysis
In the light of on going discussions about ownership models in the European football industry, this paper analyses possible effects of different ownership motivations on club performance using financial and sporting data of 84 professional European football clubs over a period of eight seasons. A univariate model and a multiple linear regression model are applied in the analysis. The results provide evidence supporting the assumption that strategically motivated owners prioritize win-maximization over profitable operations. In contrast to the findings of existing research, this paper finds evidence for the theory that economically motivated owners tend to increase club financial leverage
Prospects for Quantum Computing with an Array of Ultracold Polar Paramagnetic Molecules
Arrays of trapped ultracold molecules represent a promising platform for
implementing a universal quantum computer. DeMille has detailed a prototype
design based on Stark states of polar molecules as qubits. Herein,
we consider an array of polar molecules which are, in addition,
inherently paramagnetic and whose Hund's case (b) free-rotor states are Bell
states. We show that by subjecting the array to combinations of concurrent
homogeneous and inhomogeneous electric and magnetic fields, the entanglement of
the array's Stark and Zeeman states can be tuned and the qubit sites addressed.
Two schemes for implementing an optically controlled CNOT gate are proposed and
their feasibility discussed in the face of the broadening of spectral lines due
to dipole-dipole coupling and the inhomogeneity of the electric and magnetic
fields.Comment: 23 Pages, 11 figures, Submitted to Journal of Chemical Physic
A Large Atom Number Metastable Helium Bose-Einstein Condensate
We have produced a Bose-Einstein condensate of metastable helium (4He*)
containing over 1.5x10^7 atoms, which is a factor of 25 higher than previously
achieved. The improved starting conditions for evaporative cooling are obtained
by applying one-dimensional Doppler cooling inside a magnetic trap. The same
technique is successfully used to cool the spin-polarized fermionic isotope
(3He*), for which thermalizing collisions are highly suppressed. Our detection
techniques include absorption imaging, time-of-flight measurements on a
microchannel plate detector and ion counting to monitor the formation and decay
of the condensate.Comment: 4 pages, 3 figures (changed content
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