5,174 research outputs found
On Sexual Lust as an Emotion
Sexual lust – understood as a feeling of sexual attraction towards another – has traditionally been viewed as a sort of desire or at least as an appetite akin to hunger. I argue here that this view is, at best, significantly incomplete. Further insights can be gained into certain occurrences of lust by noticing how strongly they resemble occurrences of “attitudinal” (“object-directed”) emotion. At least in humans, the analogy between the object-directed appetites and attitudinal emotions goes well beyond their psychological structure to include similar ways in which their occurrence can be introspectively recognized, resulting in similar extensions of their functionality and meaningfulness to the subject. I conclude that although further research is needed, given the strength of the analogy, the ability of lust to satisfy some general requirements for being an emotion, and perhaps certain neurological findings, lust may somewhat uniquely straddle the line between appetite and emotion
A simple approach to the correlation of rotovibrational states in four-atomic molecules
The problem of correlation between quantum states of four-atomic molecules in
different geometrical configurations is reviewed in detail. A general, still
simple rule is obtained which allows one to correlate states of a linear
four-atomic molecule with those of any kind of non-linear four-atomic molecule.Comment: 16 pages (+8 figures), Postscript (ready to print!
Counting statistics of tunneling through a single molecule: effect of distortion and displacement of vibrational potential surface
We analyze the effects of a distortion of the nuclear potential of a
molecular quantum dot (QD), as well as a shift of its equilibrium position, on
nonequilibrium-vibration-assisted tunneling through the QD with a single level
() coupled to the vibrational mode. For this purpose, we derive an
explicit analytical expression for the Franck-Condon (FC) factor for a
displaced-distorted oscillator surface of the molecule and establish rate
equations in the joint electron-phonon representation to examine the
current-voltage characteristics and zero-frequency shot noise, and skewness as
well. Our numerical analyses shows that the distortion has two important
effects. The first one is that it breaks the symmetry between the excitation
spectra of the charge states, leading to asymmetric tunneling properties with
respect to and . Secondly, distortion (frequency
change of the oscillator) significantly changes the voltage-activated cascaded
transition mechanism, and consequently gives rise to a different nonequilibrium
vibrational distribution from that of the case without distortion. Taken in
conjunction with strongly modified FC factors due to distortion, this results
in some new transport features: the appearance of strong NDC even for a
single-level QD with symmetric tunnel couplings; a giant Fano factor even for a
molecule with an extremely weak electron-phonon interaction; and enhanced
skewness that can have a large negative value under certain conditions.Comment: 29 pages, 11 figures, published versio
Quantum resonance, Anderson localisation and selective manipulations in molecular mixtures by ultrashort laser pulses
We demonstrate that the current laser technology used for field-free
molecular alignment via a cascade of Raman rotational transitions allows for
observing long-discussed non-linear quantum phenomena in the dynamics of the
periodically kicked rotor. This includes the scaling of the absorbed energy
near the conditions of quantum resonance and Anderson-like localisation in the
angular momentum. Based on these findings, we suggest a novel approach to
tunable selective rotational excitation and alignment in a molecular mixture,
using trains of short laser pulses. We demonstrate the efficiency of this
approach by applying it to a mixture of two nitrogen isotopologues (14N2 and
15N2), and show that strong selectivity is possible even at room temperature
Non-adiabatic Effects in the Dissociation of Oxygen Molecules at the Al(111) Surface
The measured low initial sticking probability of oxygen molecules at the
Al(111) surface that had puzzled the field for many years was recently
explained in a non-adiabatic picture invoking spin-selection rules [J. Behler
et al., Phys. Rev. Lett. 94, 036104 (2005)]. These selection rules tend to
conserve the initial spin-triplet character of the free O2 molecule during the
molecule's approach to the surface. A new locally-constrained
density-functional theory approach gave access to the corresponding
potential-energy surface (PES) seen by such an impinging spin-triplet molecule
and indicated barriers to dissociation which reduce the sticking probability.
Here, we further substantiate this non-adiabatic picture by providing a
detailed account of the employed approach. Building on the previous work, we
focus in particular on inaccuracies in present-day exchange-correlation
functionals. Our analysis shows that small quantitative differences in the
spin-triplet constrained PES obtained with different gradient-corrected
functionals have a noticeable effect on the lowest kinetic energy part of the
resulting sticking curve.Comment: 17 pages including 11 figures; related publications can be found at
http://www.fhi-berlin.mpg.de/th/th.htm
Dissociation of O2 at Al(111): The Role of Spin Selection Rules
A most basic and puzzling enigma in surface science is the description of the
dissociative adsorption of O2 at the (111) surface of Al. Already for the
sticking curve alone, the disagreement between experiment and results of
state-of-the-art first-principles calculations can hardly be more dramatic. In
this paper we show that this is caused by hitherto unaccounted spin selection
rules, which give rise to a highly non-adiabatic behavior in the O2/Al(111)
interaction. We also discuss problems caused by the insufficient accuracy of
present-day exchange-correlation functionals.Comment: 4 pages including 3 figures; related publications can be found at
http://www.fhi-berlin.mpg.de/th/th.htm
Molecular Dipolar Crystals as High Fidelity Quantum Memory for Hybrid Quantum Computing
We study collective excitations of rotational and spin states of an ensemble
of polar molecules, which are prepared in a dipolar crystalline phase, as a
candidate for a high fidelity quantum memory. While dipolar crystals are formed
in the high density limit of cold clouds of polar molecules under 1D and 2D
trapping conditions, the crystalline structure protects the molecular qubits
from detrimental effects of short range collisions. We calculate the lifetime
of the quantum memory by identifying the dominant decoherence mechanisms, and
estimate their effects on gate operations, when a molecular ensemble qubit is
transferred to a superconducting strip line cavity (circuit QED). In the case
rotational excitations coupled by dipole-dipole interactions we identify
phonons as the main limitation of the life time of qubits. We study specific
setups and conditions, where the coupling to the phonon modes is minimized.
Detailed results are presented for a 1D dipolar chain
Distributed Relay Protocol for Probabilistic Information-Theoretic Security in a Randomly-Compromised Network
We introduce a simple, practical approach with probabilistic
information-theoretic security to mitigate one of quantum key distribution's
major limitations: the short maximum transmission distance (~200 km) possible
with present day technology. Our scheme uses classical secret sharing
techniques to allow secure transmission over long distances through a network
containing randomly-distributed compromised nodes. The protocol provides
arbitrarily high confidence in the security of the protocol, with modest
scaling of resource costs with improvement of the security parameter. Although
some types of failure are undetectable, users can take preemptive measures to
make the probability of such failures arbitrarily small.Comment: 12 pages, 2 figures; added proof of verification sub-protocol, minor
correction
Animal models of chronic pain. Are naturally occurring diseases a potential model for translational research?
Despite the vast amount of molecular data obtained from classical pain studies, there is an ongoing translational pain model crisis reflected by the reduced amount of new effective and safe compounds developed to treat chronic pain in humans. Naturally occurring chronic pain in animals may offer some advantages over induced models of chronic pain, including a natural development of the condition that induces pain, the heterogenicity of the population that affects, and the chronologic age in which they develop, among others. The identification and study of naturally occurring painful diseases that resemble a particular chronic painful condition in humans has been proposed as a potential tool to investigate the molecular mechanisms and thus, accelerating drug development at the preclinical and clinical level. Currently, certain types of chronic pain in companion and large animals have gained attention as potential translational models of chronic pain. Examples of these include canine and feline osteoarthritis, neoplastic diseases as osteosarcoma and bovine and equine lameness. The present review describes the limitations of animal models of chronic pain and briefly enters in how naturally occurring pain models could represent a translational approach to chronic pain
Relative and center-of-mass motion in the attractive Bose-Hubbard model
We present first-principle numerical calculations for few particle solutions
of the attractive Bose-Hubbard model with periodic boundary conditions. We show
that the low-energy many-body states found by numerical diagonalization can be
written as translational superposition states of compact composite systems of
particles. These compact states break the translational symmetry of the problem
and their center-of-mass and internal excitations offer simple explanations of
the energy spectrum of the full model.Comment: 12 pages, 9 figure
- …