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111.
We discuss three Hamiltonians, each with a central-field part H0 and a PT-symmetric perturbation igz. When H0 is the isotropic Harmonic oscillator the spectrum is real for all g because H is isospectral to H0+g2/2. When H0 is the Hydrogen atom then infinitely many eigenvalues are complex for all g. If the potential in H0 is linear in the radial variable r then the spectrum of H exhibits real eigenvalues for 0<g<gc and a PT phase transition at gc. 相似文献
112.
113.
Frieder Kleefeld 《Czechoslovak Journal of Physics》2006,56(9):999-1006
A simple derivation of a meaningful, manifestly covariant inner product for real Klein—Gordon (KG) fields with positive semi-definite
norm is provided, which turns out — assuming a symmetric bilinear form — to be the real-KG-field limit of the inner product
for complex KG fields reviewed by A. Mostafazadeh and F. Zamani in December 2003, and February 2006 (quant-ph/0312078, quant-ph/0602151,
quant-ph/0602161). It is explicitly shown that the positive semi-definite norm associated with the derived inner product for
real KG fields measures the number of active positive and negative energy Fourier-modes of the real KG field on the relativistic
mass shell. The very existence of an inner product with positive semi-definite norm for the considered real, i.e. neutral,
KG fields shows that the metric operator entering the inner product does not contain the charge-conjugation operator. This
observation sheds some additional light on the meaning of the C operator in the CPT inner product of PT-symmetric quantum
mechanics defined by C.M. Bender, D.C. Brody and H.F. Jones. 相似文献
114.
Young Joon Ko Yong Keun ParkByung Kil Yun Minbaek LeeJong Hoon Jung 《Current Applied Physics》2014,14(11):1486-1491
We report the pyroelectric power generation of a relaxor ferroelectric 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 (PMN–PT) single crystal. For a temperature variation rate of 0.5 K/s, the PMN–PT generated a closed-circuit current of 10 nA and an open-circuit voltage of 1.1 V at room temperature. The pyroelectric current and voltage of the PMN–PT single crystal were proportional to the temperature variation rate and were sharply enhanced near the structural phase-transition temperature. Additionally, the PMN–PT pyroelectric generator produced stable power for excessive thermal cycling and was highly sensitive to random thermal fluctuations. Our results indicate the potential importance of PMN–PT for high-power pyroelectric generator applications. 相似文献
115.
Zafar Ahmed 《Czechoslovak Journal of Physics》2004,54(10):1011-1018
Attention has been brought to the possibility that statistical fluctuation properties of several complex spectra, or well-known number sequences, may display strong signatures that the Hamiltonian yielding them as eigenvalues is PT-symmetric (pseudo-Hermitian). We find that the random matrix theory of pseudo-Hermitian Hamiltonians gives rise to new universalities of level-spacing distributions other than those of GOE, GUE and GSE of Wigner and Dyson. We call the new proposals as Gaussian Pseudo-Orthogonal Ensemble and Gaussian Pseudo-Unitary Ensemble. We are also led to speculate that the enigmatic Riemann-zeros (1/2±it
n
would rather correspond to some PT-symmetric (pseudo-Hermitian) Hamiltonian. 相似文献
116.
这里从泛系观引入一种的哲学与数学研究,包括在乏系框架下 发展哲学七论与数学和一些第二第三哲学以及对事理、物理、技理、医理与战理的某些应用。 相似文献
117.
Elastic–plastic deformation of Pb(Zn1/3Nb2/3)O3–(6–7)% PbTiO3 single crystals during nanoindentation
Meng Fei Wong 《哲学杂志》2013,93(13):1685-1700
The elastic–plastic deformation behavior of (001)- and (011)-oriented single crystal solid solutions of Pb(Zn1/3Nb2/3)O3–(6–7)% PbTiO3 (PZN–PT) have been studied using a nanoindentation technique. A procedure is presented here to isolate the elastic, elastic–plastic and plastic contributions to the deformation using the unloading data, and a parameter, referred to as relaxation, is defined to characterize the elastic–plastic deformation during nanoindentations. This relaxation parameter increases with the maximum indentation load due to the higher indentation stress induced, and it also causes less recovery of the material upon indentation unloading compared to predicted pure elastic recovery. For a (001) surface, the relaxation value remains virtually unchanged within the range of the maximum indentation load of 10–50 mN, possibly due to a complete localized depoling of the non-180° domain switching. It is also found that the unpoled surface is more prone to stress-induced depolarization compared to the poled surfaces. Furthermore, by applying the continuous stiffness measurement (CSM) technique, the effects of multiple loading/unloading are studied for both (001)- and (011)-oriented PZN–PTs using the maximum indentation loads of 20 and 50 mN. With more loading/unloading cycles at higher CSM frequencies, stress-induced depolarization becomes prevalent and the contribution of the domain reorientation towards elastic recovery is significantly reduced. As a consequence, the relaxation value is increased, indicating more elastic–plastic deformation. This CSM effect is especially pronounced for poled (011) surfaces. 相似文献
118.
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120.
O. Bercaru M. Ricci F. Ulberth C. Brunori R. Morabito I. Ipolyi A. Sahuquillo E. Rosenberg 《Trends in analytical chemistry : TRAC》2009,28(9):1073-1081
In accordance with Article 8 of the European Union (EU) Water Framework Directive (WFD), EU Member States are required to establish monitoring programs for the quality of the surface water and the groundwater within each river-basin district. As such data are the basis for regulatory decisions and measures required to achieve WFD environmental objectives, appropriate analytical quality-assurance and quality-control tools have to be implemented by the monitoring laboratories. In this respect, reference materials (RMs) play a key role. Within the framework of the SWIFT-WFD project (Screening methods for Water data InFormation in support of the WFD), several approaches to the preparation of matrix RMs for the analysis of polycyclic aromatic hydrocarbons and pesticides in water have been used in wide-scale proficiency-testing (PT) schemes. We present the different strategies employed in preparing water-matrix RMs for organic analytes. By reviewing the results from the SWIFT-WFD PT schemes, we reflect on the applicability and the suitability of the different approaches. 相似文献