共查询到20条相似文献,搜索用时 15 毫秒
1.
H. Naik T. Datta S. P. Dange P. K. Pujari S. Prakash M. V. Ramaniah 《Zeitschrift für Physik A Hadrons and Nuclei》1988,331(3):335-342
In the present work angular momenta of the fragments corresponding to132Im,g have been deduced from the radiochemically determined independent isomeric yield ratios and statistical model based analysis in neutron induced fission of235U,239Pu and245Cm and spontaneous fission of252Cf. These data along with similar data on134I, reported earlier from this laboratory, bring out the effects of deformed 66n and spherical 82n shells on fragment angular momentum showing also an inverse correlation of the latter with elemental yields. Quantitative estimates of fragment scission point deformation and the coefficient of change of fragment angular momentum with kinetic/excitation energy have been deduced and are seen to be in good agreement with the expected theoretical estimates. 相似文献
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To test whether the theory of macroscopic quantum tunneling (MQT) is applicable to systems with 2 degrees of freedom, we experimentally investigated the switching current distribution of a dc SQUID. Using sample parameters determined from measurements at T=4.2 K, we are able to make quantitative comparison to the theories from 8 mK to 4.2 K. The excellent agreement between the data and the MQT theory demonstrates that tunneling from the zero-voltage state of the dc SQUID is well described by the quantum mechanics. 相似文献
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The structure of the interaction of giant dipole and giant quadrupole oscillations with nuclear surface vibrations is established. The various coupling parameters are calculated in the hydrodynamic model. The significance of the interaction terms is discussed. 相似文献
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Yamen Hamdouni 《Physics letters. A》2009,373(14):1233-1238
We derive analytical properties for the degeneracy ν(N,j) occurring in the decomposition of the state space C2⊗N. We also investigate the dynamics of two qubits coupled via Ising interactions to separate spin baths, and we study the thermodynamic limit. 相似文献
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T. Datta S. P. Dange S. M. Sahakundu S. Prakash M. V. Ramaniah 《Zeitschrift für Physik A Hadrons and Nuclei》1988,330(1):103-109
In the present work rms angular momenta have been deduced for the fission fragments corresponding to131Tem,g and133Tem,g in232Th(α 40 MeV,f) and238U(α 40 MeV,f) systems from the radiochemically determined independent isomeric yield ratios and statistical model based analysis. For131Te and133Te the rms angular momenta deduced are 5.9±1.0 and 7.9±1.2 ? respectively in232Th(α 40 MeV,f) and 7.2±0.6 and 8.0±0.8 ? respectively in238U(α 40 MeV,f). Comparison of the present data with the literature data for these fragments in the same compound nuclei236U* and242Pu* at lower excitation energies shows increase in the fragment angular momentum with increasing excitation energy and angular momenta of the fissioning nuclei. Fragment angular momentum deduced theoretically for asymmetric and deformed fragments on the basis of thermal equilibration of the collective rotational degrees e.g., rigid rotation, wriggling, tilting, bending and twisting modes considering the effect of multichance fission, are in good agreement with the experimental observations. 相似文献
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量子通信是一个量子密钥分发过程,目前采用的通信技术严重制约了量子密钥分发的比特率.将多输入多输出(MIMO)技术应用于量子通信系统,提高量子密钥分发的比特率,促进量子通信向高速大容量发展.然而,量子场本身不可避免地存在量子噪声约束容量的增长,限制了可利用空间资源,即空间自由度.文中采用光子场的量子化和满足Schrdinger方程条件的电磁场波动方程推导出MIMO量子信道的空间自由度上限,为开发稳健的MIMO量子通信空时处理算法和优化设计高性能MIMO量子通信系统提供理论基础和技术支持.
关键词:
多输入多输出
量子密钥分发
Schrdinger方程
光子场的量子化 相似文献
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The barrier-penetration problem in the presence of couplings to intrinsic degrees of freedom is discussed in a framework suitable for describing heavy-ion fusion reactions. The inward-outward integration formulation with an ingoing-wave boundary condition leads to an efficient algorithm for numerical calculations. Short-wavelength approximations are introduced to obtain semi-quantal equations. These are used to derive the leading-order effects of the coupling on the barrier-penetration probability for the general case and to solve a coupled-harmonic-oscillator problem to all orders. The characteristic enhancement of the penetration due to the coupling in the barrier region and the interference between the inside and outside regions are discussed. 相似文献
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Various models have been proposed in order to understand the near barrier heavy-ion fusion data. Amongst others the coupled
channel approach of Dasso and Landowne and the neutron flow picture of Stelson are two of the mechanisms which describe well
a large body of near barrier fusion data. From an analysis of16O induced fusion reaction around the barrier for various targets an attempt has been made to identify which out of the above
two mechanisms is more appropriate to explain these data. 相似文献
11.
Measurement-device-independent quantum key distribution(MDI-QKD)provides us a powerful approach to resist all attacks at detection side.Besides the unconditional security,people also seek for high key generation rate,but MDI-QKD has relatively low key generation rate.In this paper,we provide an efficient approach to increase the key generation rate of MDI-QKD by adopting multiple degrees of freedom(DOFs)of single photons to generate keys.Compared with other high-dimension MDI-QKD protocols encoding in one DOF,our protocol is more flexible,for our protocol generating keys in independent subsystems and the detection failure or error in a DOF not affecting the information encoding in other DOFs.Based on above features,our MDI-QKD protocol may have potential application in future quantum comniunication field. 相似文献
12.
Bojowald M 《Physical review letters》2005,95(6):061301
Spherically symmetric space-times provide many examples for interesting black hole solutions, which classically are all singular. Following a general program, space-like singularities in spherically symmetric quantum geometry, as well as other inhomogeneous models, are shown to be absent. Moreover, one sees how the classical reduction from infinitely many kinematical degrees of freedom to only one physical one, the mass, can arise, where aspects of quantum cosmology such as the problem of initial conditions play a role. 相似文献
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Y. Chizaki H. Kashiwaya S. Kashiwaya T. Koyama S. Kawabata 《Physica C: Superconductivity and its Applications》2011,471(21-22):758-759
We theoretically study macroscopic quantum tunneling (MQT) in capacitively coupled Josephson junctions in the case that one of the junctions is in the finite voltage state. We find that the system can be mapped into a one dimensional model with a spontaneous periodic perturbation and calculate the MQT rate by using the time-dependent WKB method. Then the MQT rate is found to be resonantly enhanced and the enhancement of MQT rate is found even off the resonant point. 相似文献
16.
S.N.M Ruijsenaars 《Annals of Physics》1980,128(2):335-362
We study one-dimensional quantum systems whose S-operator conserves the incoming momenta and particle identities. A survey of systems with known S-operators and an approach for solving them rigorously are presented, and several problems and conjectures are formulated. Subsequently, this approach is used to arrive at relativistic dynamics whose S-operators are those of the Ising model in the scaling limit and of the Federbush model. An invariance property of the wave and scattering operators is discovered and argued to hold at the classical level, too. 相似文献
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We demonstrate a method to describe quantum systems with infinitely many degrees of freedom in concrete Hilbert spaces, using the electromagnetic radiation field as a well-known example of such a system. Since our method is not only applicable to the case of countably many but even to the case of uncountably many degrees of freedom, there is no need for a finite quantization volume in radiation theory. 相似文献
20.
Breakdown of Landau Fermi liquid theory: Restrictions on the degrees of freedom of quantum electrons
One challenge in contemporary condensed matter physics is to understand unconventional electronic physics beyond the paradigm of Landau Fermi-liquid theory. Here, we present a perspective that posits that most such examples of unconventional electronic physics stem from restrictions on the degrees of freedom of quantum electrons in Landau Fermi liquids. Since the degrees of freedom are deeply connected to the system’s symmetries and topology, these restrictions can thus be realized by external constraints or by interaction-driven processes via the following mechanisms: (i) symmetry breaking, (ii) new emergent symmetries, and (iii) nontrivial topology. Various examples of unconventional electronic physics beyond the reach of traditional Landau Fermi liquid theory are extensively investigated from this point of view. Our perspective yields basic pathways to study the breakdown of Landau Fermi liquids and also provides a guiding principle in the search for novel electronic systems and devices. 相似文献