Spin splitting of X-related donor impurity states in an AlAs barrier

We use magnetotunneling spectroscopy to observe the spin splitting of the ground state of an X-valley-related Si-donor impurity in an AlAs barrier. We determine the absolute magnitude of the effective Zeeman spin splitting factors of the impurity ground state to be g$_{I}$= 2.2 $\pm$ 0.1. We also investigate the spatial form of the electron wave function of the donor ground state, which is anisotropic in the growth plane

Tuning the onset voltage of resonant tunneling through InAs quantum dots by growth parameters

We investigated the size dependence of the ground state energy in self-assembled InAs quantum dots embedded in resonant tunneling diodes. Individual current steps observed in the current-voltage characteristics are attributed to resonant single-electron tunneling via the ground state of individual InAs quantum dots. The onset voltage of the first step observed is shown to decrease systematically from 200 mV to 0 with increasing InAs coverage. We relate this to a coverage-dependent size of InAs dots grown on AlAs. The results are confirmed by atomic force micrographs and photoluminescence experiments on reference samples.Comment: 3 pages, 3 figure

Magnetic-field-induced singularities in spin dependent tunneling through InAs quantum dots

Current steps attributed to resonant tunneling through individual InAs quantum dots embedded in a GaAs-AlAs-GaAs tunneling device are investigated experimentally in magnetic fields up to 28 T. The steps evolve into strongly enhanced current peaks in high fields. This can be understood as a field-induced Fermi-edge singularity due to the Coulomb interaction between the tunneling electron on the quantum dot and the partly spin polarized Fermi sea in the Landau quantized three-dimensional emitter.Comment: 5 pages, 4 figure

REMOTE INFLUENCE OF HUMAN PHYSIOLOGY BY A RITUAL HEALING TECHNIQUE

Two experiments tested the hypothesis that remote calming effects of a traditional healing ritual can be objectively measured using indicators of electrodermal activity, heart rate and blood volume. A total of 14 sessions were conducted in the initial study and 16 sessions were conducted in the replication. In both experiments, the authors exchanged roles as experimenter, healer and patient. Healers were instructed to try to calm the remote patient using a set of traditional ritual magic strategies, or to exert no influence (as a control). The patient created a doll in his or her likeness and provided mementos, pictures and an autobiographical sketch. The healer used these materials to form a sympathetic connection with the patient who was located in another building in an isolated toom. During the experiments, there were no other connections between the healer and the patient. Each session consisted of a randomized counterbalanced sequence of five calming and five control epochs of one minute each. No performance feedback was provided to the healer or patient during the session. The combined results of both experiments showed significant effects for changes in blood volume (p = .00002), heart rate (p = .001) and electrodermal activity (p = .013), suggesting that traditional magic healing rituals caused significant relaxation of the vascular system and arousal of electrodermal activity. These rituals appear to be helpful in focusing mental intention in laboratory investigations of direct mental interactions with living systems

REMOTE INFLUENCE OF HUMAN PHYSIOLOGY BY A RITUAL HEALING TECHNIQUE

Two experiments tested the hypothesis that remote calming effects of a traditional healing ritual can be objectively measured using indicators of electrodermal activity, heart rate and blood volume. A total of 14 sessions were conducted in the initial study and 16 sessions were conducted in the replication. In both experiments, the authors exchanged roles as experimenter, healer and patient. Healers were instructed to try to calm the remote patient using a set of traditional ritual magic strategies, or to exert no influence (as a control). The patient created a doll in his or her likeness and provided mementos, pictures and an autobiographical sketch. The healer used these materials to form a sympathetic connection with the patient who was located in another building in an isolated toom. During the experiments, there were no other connections between the healer and the patient. Each session consisted of a randomized counterbalanced sequence of five calming and five control epochs of one minute each. No performance feedback was provided to the healer or patient during the session. The combined results of both experiments showed significant effects for changes in blood volume (p = .00002), heart rate (p = .001) and electrodermal activity (p = .013), suggesting that traditional magic healing rituals caused significant relaxation of the vascular system and arousal of electrodermal activity. These rituals appear to be helpful in focusing mental intention in laboratory investigations of direct mental interactions with living systems

Analysis of Granular Packing Structure by Scattering of THz Radiation

Scattering methods are widespread used to characterize the structure and constituents of matter on small length scales. This motivates this introductory text on identifying prospective approaches to scattering-based methods for granular media. A survey to light scattering by particles and particle ensembles is given. It is elaborated why the established scattering methods using X-rays and visible light cannot in general be transferred to granular media. Spectroscopic measurements using Terahertz radiation are highlighted as they to probe the scattering properties of granular media, which are sensitive to the packing structure. Experimental details to optimize spectrometer for measurements on granular media are discussed. We perform transmission measurements on static and agitated granular media using Fourier-transform spectroscopy at the THz beamline of the BessyII storage ring. The measurements demonstrate the potential to evaluate degrees of order in the media and to track transient structural states in agitated bulk granular media.Comment: 12 Pages, 9 Figures, 56 Reference

Shot noise of coupled semiconductor quantum dots

The low-frequency shot noise properties of two electrostatically coupled semiconductor quantum dot states which are connected to emitter/collector contacts are studied. A master equation approach is used to analyze the bias voltage dependence of the Fano factor as a measure of temporal correlations in tunneling current caused by Pauli's exclusion principle and the Coulomb interaction. In particular, the influence of the Coulomb interaction on the shot noise behavior is discussed in detail and predictions for future experiments will be given. Furthermore, we propose a mechanism for negative differential conductance and investigate the related super-Poissonian shot noise.Comment: submitted to PR

Strong quantum memory at resonant Fermi edges revealed by shot noise

Studies of non-equilibrium current fluctuations enable assessing correlations involved in quantum transport through nanoscale conductors. They provide additional information to the mean current on charge statistics and the presence of coherence, dissipation, disorder, or entanglement. Shot noise, being a temporal integral of the current autocorrelation function, reveals dynamical information. In particular, it detects presence of non-Markovian dynamics, i.e., memory, within open systems, which has been subject of many current theoretical studies. We report on low-temperature shot noise measurements of electronic transport through InAs quantum dots in the Fermi-edge singularity regime and show that it exhibits strong memory effects caused by quantum correlations between the dot and fermionic reservoirs. Our work, apart from addressing noise in archetypical strongly correlated system of prime interest, discloses generic quantum dynamical mechanism occurring at interacting resonant Fermi edges.Comment: 6 pages, 3 figure

Criticality Analysis of Activity Networks under Interval Uncertainty

Dedicated to the memory of Professor Stefan Chanas - The extended abstract version of this paper has appeared in Proceedings of 11th International Conference on Principles and Practice of Constraint Programming (CP2005) ("Interval Analysis in Scheduling", Fortin et al. 2005)International audienceThis paper reconsiders the Project Evaluation and Review Technique (PERT) scheduling problem when information about task duration is incomplete. We model uncertainty on task durations by intervals. With this problem formulation, our goal is to assert possible and necessary criticality of the different tasks and to compute their possible earliest starting dates, latest starting dates, and floats. This paper combines various results and provides a complete solution to the problem. We present the complexity results of all considered subproblems and efficient algorithms to solve them

Measurement of triple gauge boson couplings from WW production at LEP energies up to 189 GeV

A measurement of triple gauge boson couplings is presented, based on W-pair data recorded by the OPAL detector at LEP during 1998 at a centre-of-mass energy of 189 GeV with an integrated luminosity of 183 pb^-1. After combining with our previous measurements at centre-of-mass energies of 161-183 GeV we obtain k_g=0.97 +0.20 -0.16, g_1^z=0.991 +0.060 -0.057 and lambda_g=-0.110 +0.058 -0.055, where the errors include both statistical and systematic uncertainties and each coupling is determined by setting the other two couplings to their SM values. These results are consistent with the Standard Model expectations.Comment: 28 pages, 8 figures, submitted to Eur. Phys. J.