Quantum anti-Zeno effect in artificial quantum systems

In this paper, we study a quantum anti-Zeno effect (QAZE) purely induced by repetitive measurements for an artificial atom interacting with a structured bath. This bath can be artificially realized with coupled resonators in one dimension and possesses photonic band structure like Bloch electron in a periodic potential. In the presence of repetitive measurements, the pure QAZE is discovered as the observable decay is not negligible even for the atomic energy level spacing outside of the energy band of the artificial bath. If there were no measurements, the decay would not happen outside of the band. In this sense, the enhanced decay is completely induced by measurements through the relaxation channels provided by the bath. Besides, we also discuss the controversial golden rule decay rates originated from the van Hove's singularities and the effects of the counter-rotating terms.Comment: 12 pages, 8 figure

Effective Focal Area Dimension Optimization of Shear Horizontal Point-Focusing EMAT Using Orthogonal Test Method

To overcome the shortcomings of low energy conversion efficiency of electromagnetic acoustic transducers (EMATs), point-focusing shear horizontal (PFSH) wave EMAT is used to focus the wave energy into a specific area. Many factors will affect the capability of the focusing transducer, and in addition to considering the signal intensity, the detection accuracy is also required to be investigated. Specifically, to simplify the test process, we use the orthogonal test method to study the effect of different influence parameters on signal intensity and focal area dimensions. Seven factors are selected, and three results are determined in the test. Range analysis shows that for signal amplitude M , the top three impact factors are the coil width w , coil turns n , and focal length lF (equal to bandwidth factor α ). Moreover, magnet number m and frequency fc dominate the effective focal length lfd , and aperture angle θ determines the effective focal width wfd . To enable higher signal intensity and smaller focal area dimensions, it is necessary to consider various factors on the PFSH-EMAT focusing performance. The test’s signal intensity with optimized parameters’ combination at the focal point is nearly 144.42% higher than the average of all the tests, lfd decreased by 37.84%, and wfd decreased by 50.59%. The experiment also verified that focusing EMAT with optimized parameters has a better focusing performance

Defect detection and identification of point-focusing shear-horizontal EMAT for plate inspection

As a kind of nondestructive testing (NDT) method, shear-horizontal (SH)-guided wave detection technology is widely used on an electromagnetic acoustic transducer (EMAT). Although ultrasonic-guided waves perform well in defect location, it is difficult to obtain detailed information about defects, and the low efficiency of EMAT energy conversion still reduces the EMAT’s performance. Therefore, in this work, the defect detection method of different shapes and sizes by point-focusing shear-horizontal (PFSH)-guided wave EMAT with the use of periodic permanent magnet (PPM) is investigated through simulation and experiment. For the purpose of defect classification and quantification, the extraction principles of defect features are obtained through simulation based on the circumferential scatter diagrams, and the neural network (NN) is used to process the features extracted from the experimental data. The results show that by extracting effective defect features from the scatter diagram, high-accuracy classification and high-precision quantification of defects under the influence of the focusing transducer can be achieved

Anomalous rotational-alignment in N=Z nuclei and residual neutron-proton interaction

Recent experiments have demonstrated that the rotational-alignment for the $N=Z$ nuclei in the mass-80 region is considerably delayed as compared to the neighboring $N \ne Z$ nuclei. We investigate whether this observation can be understood by a known component of nuclear residual interactions. It is shown that the quadrupole-pairing interaction, which explains many of the delays known in rare-earth nuclei, does not produce the substantial delay observed for these $N=Z$ nuclei. However, the residual neutron-proton interaction which is conjectured to be relevant for $N=Z$ nuclei is shown to be quite important in explaining the new experimental data.Comment: 4 pages, 3 figures, final version accepted by Phys. Rev. C as a Rapid Communicatio

Quark and Nucleon Self-Energy in Dense Matter

In a recent work we introduced a nonlocal version of the Nambu--Jona-Lasinio(NJL) model that was designed to generate a quark self-energy in Euclidean space that was similar to that obtained in lattice simulations of QCD. In the present work we carry out related calculations in Minkowski space, so that we can study the effects of the significant vector and axial-vector interactions that appear in extended NJL models and which play an important role in the study of the $\rho$, $\omega$ and $a_1$ mesons. We study the modification of the quark self-energy in the presence of matter and find that our model reproduces the behavior of the quark condensate predicted by the model-independent relation $_{\rho} = <\bar qq>_0(1-\sigma_N\rho_N/f_{\pi}^2m_{\pi}^2 +...)$, where $\sigma_N$ is the pion-nucleon sigma term and $\rho_N$ is the density of nuclear matter. (Since we do not include a model of confinement, our study is restricted to the analysis of quark matter. We provide some discussion of the modification of the above formula for quark matter.) The inclusion of a quark current mass leads to a second-order phase transition for the restoration of chiral symmetry. That restoration is about 80% at twice nuclear matter density for the model considered in this work. We also find that the part of the quark self-energy that is explicitly dependent upon density has a strong negative Lorentz-scalar term and a strong positive Lorentz-vector term, which is analogous to the self-energy found for the nucleon in nuclear matter when one makes use of the Dirac equation for the nucleon. In this work we calculate the nucleon self -energy in nuclear matter using our model of the quark self-energy and obtain satisfactory results.Comment: 19 pages, 8 figures, 2 tables, revte

Stress detection using wearable physiological sensors

As the population increases in the world, the ratio of health carers is rapidly decreasing. Therefore, there is an urgent need to create new technologies to monitor the physical and mental health of people during their daily life. In particular, negative mental states like depression and anxiety are big problems in modern societies, usually due to stressful situations during everyday activities including work. This paper presents a machine learning approach for stress detection on people using wearable physiological sensors with the �final aim of improving their quality of life. The presented technique can monitor the state of the subject continuously and classify it into "stressful" or "non-stressful" situations. Our classification results show that this method is a good starting point towards real-time stress detection

A calculus for generic, QoS-aware component composition

Software QoS properties, such as response time, availability, bandwidth requirement, memory usage, among many others, play a major role in the processes of selecting and composing software components. This paper extends a component calculus to deal, in an effective way, with them. The calculus models components as generalised Mealy machines, i.e., state-based entities interacting along their life time through well defined interfaces of observers and actions. QoS is introduced through an algebraic structure specifying the relevant QoS domain and how its values are composed under different disciplines. A major effect of introducing QoS-awareness is that a number of equivalences holding in the plain calculus become refinement laws. The paper also introduces a prototyper for the calculus developed as a ‘proof-of-concept’ implementation.FCT -Fuel Cell Technologies Program(FCOMP-01-0124-FEDER-020537

Response of an Indented Square Tube under Impact Loading

The dynamic buckling of the square tube with a V-shape indent under impact loading was investigated by experimental and numerical methods. The collapse modes of square tubes with different locations of indentation points were obtained experimentally. Numerical calculations of each experimental load case were conducted to analyze the effect of the indentation point location on the crush force and energy absorption of the tube. Numerical results agree well with the experimental ones. The results show that the indentation point location exerts a significant influence on the crush force and energy absorption. Compared to an indentation-free tube, the peak force of the indented tube is evidently reduced. The collapse process of the tube includes two buckling steps. The first one begins from the indentation either forward or backward with respect to the end until the folds are densified, then the second buckling starts backward or forward, which results in a second peak force in the collapse process.Динамическое коробление квадратной трубки с V-образным отпечатком в условиях ударного нагружения исследовано экспериментальными и численными методами. Режимы сплющивания квадратных трубок с различным расположением точек индентирования реализовывали экспериментально. Выполнены численные расчеты каждого случая экспериментального нагружения с целью анализа влияния месторасположения точки индентирования на разрушающее усилие и энергию поглощения квадратной трубки. Численные результаты хорошо согласуются с экспериментом. Установлено, что расположение точки индентирования оказывает значительное влияние на разрушающее усилие и энергию поглощения. По сравнению с неиндентированной трубкой максимальное усилие, действующее на индентированную трубку, явно уменьшается. Процесс сплющивания трубки включает два этапа коробления. Первый начинается с индентирования вперед или назад относительно конца до тех пор, пока не происходит уплотнения складок, второй осуществляется назад или вперед , что создает в результате второе максимальное усилие

Dynamically generated resonances from the vector octet-baryon decuplet interaction

We study the interaction of the octet of vector mesons with the decuplet of baryons using Lagrangians of the hidden gauge theory for vector interactions. The unitary amplitudes in coupled channels develop poles that can be associated with some known baryonic resonances, while there are predictions for new ones at the energy frontier of the experimental research. The work offers guidelines on how to search for these resonances

Quasiparticle spectrum of the hybrid s+g-wave superconductors YNi_2B_2C and LuNi_2B_2C

Recent experiments on single crystals of YNi$_2$B$_2$C have revealed the presence of point nodes in the superconducting energy gap Delta(k} at k = (1,0,0), (0,1,0), (-1,0,0), and (0,-1,0). In this paper we investigate the effects of impurity scattering on the quasiparticle spectrum in the vortex state of s+g-wave superconductors, which is found to be strongly modified in the presence of disorder. In particular, a gap in the quasiparticle energy spectrum is found to open even for infinitesimal impurity scattering, giving rise to exponentially activated thermodynamic response functions, such as the specific heat, the spin susceptibility, the superfluid density, and the nuclear spin lattice relaxation. Predictions derived from this study can be verified by measurements of the angular dependent magnetospecific heat and the magnetothermal conductivity.Comment: 8 pages, RevTex, 4 figure