共查询到20条相似文献,搜索用时 31 毫秒
1.
A.V. Andreev 《Physics letters. A》2008,372(21):3841-3845
The problem on the relativistic spinless and spin-1/2 particle motion in the Coulomb field is analyzed. The eigenvalues and eigenfunctions of particle and antiparticle bound states are calculated. The calculated spectra include the deeply bound states with the binding energy approximately equal to the particle rest mass. The antiparticle bound states play an important role in the atomic capture, radiative decay of hadronic atoms, and collision processes accompanied by recharging of reaction fragments. 相似文献
2.
The equal time limit of commutator matrix elements of conserved currents is rigorously calculated by means of structures which follow from general principles of relativistic quantum field theory and current conservation. We prove: (a) In general derivatives of δ-functions occur (gradient terms). — (b) The proper (non-gradient) part of the equal time limit is exactly given by the divergence-free causal one particle structures constructed from those intermediate one particle states which have the same main quantum numbers (mass, total spin and total isospin) as one of the external states (saturation by two one particles states!). — (c) All the other intermediate discrete one particle states drop out completely and the continuous many particle states contribute at most to gradient terms. — (d) The gradient terms emerging from the remaining two discrete intermediate one particle states can be removed without any restrictions on the form factors. — (e) From current algebras of conserved currents in the form proposed and used in the literature one cannot deduce any predictions for form factors beyond the algebraic conditions for coupling constants which already follow from the algebra of the charges. 相似文献
3.
An efficient two-step quantum key distribution (QKD) protocol with
orthogonal product states in the n\otimes n(n\geq3)Hilbert space
is presented. In this protocol, the particles in the orthogonal
product states form two particle sequences. The sender, Alice, first
sends one sequence to the receiver, Bob. After Bob receives the first
particle sequence, Alice and Bob check eavesdropping by measuring a
fraction of particles randomly chosen. After ensuring the security of
the quantum channel, Alice sends the other particle sequence to Bob.
By making an orthogonal measurement on the two particle sequences,
Bob can obtain the information of the orthogonal product states sent
by Alice. This protocol has many distinct features such as great
capacity, high efficiency in that it uses all orthogonal product
states in distributing the key except those chosen for checking
eavesdroppers. 相似文献
4.
5.
A new model is proposed for calculating angular distributions in preequilibrium reactions. In this model, as in the model of Feshbach et al. the system consisting of target plus projectile initially branches into two sets of states with either no particle in the continuum (multistep compound states) or with at least one particle in the continuum (multistep direct states). The multistep compound emission is assumed to be isotropic while the angular distribution of the multistep direct emission is described using the fast particle model of Mantzouranis et al. A similar master equation is used for both chains of states differing only in the angular dependence of the emission rates. The two chains of states are treated independantly neglecting inter-branch transitions. The angular distributions for 14.6 MeV neutrons calculated using this model are found to be in better agreement with the data than the fast particle model. 相似文献
6.
Single and two particle properties in a dense plasma are discussed in connection with their role in the mass action law for a partially ionized plasma. The two particle bound states are nearly density independent, while the continuum is essentially shifted. The single particle states are damped, and their energy has a negative shift and a parabolic behaviour for small momenta. 相似文献
7.
V. V. Dodonov I. M. Dremin O. V. Man’ko V. I. Man’ko P. G. Polynkin 《Journal of Russian Laser Research》1998,19(5):427-464
The primary aim of the present paper is to draw the attention of particle physicists to new developments in studying squeezed and correlated states of the electromagnetic field, and those working on the latest developments to new findings about multiplicity distributions and other specific effects in quantum chromodynamics. New types of nonclassical states used in quantum optics such as squeezed states, correlated states, and even and odd coherent states (Schrödinger cat states) for one-mode and multimode interactions are reviewed. Their distribution functions are analyzed according to the method first used for multiplicity distributions in high-energy particle interactions. The phenomenon of oscillations of particle distribution functions of squeezed fields is described and related to the phenomenon of oscillations of cumulant moments of some distributions for squeezed and correlated field states. Possible extension of the method to fields different from the electromagnetic field (gluons, pions, etc.) is conjectured, and some predictions of specific effects in nucleus-nucleus interactions at high energies are presented. 相似文献
8.
R. A. Nymmik 《Bulletin of the Russian Academy of Sciences: Physics》2013,77(5):490-492
The charge states of He, C, O, and Fe ions are determined for 51 gradual solar energetic particle (SEP) events of solar cycle 23 using the parameters of the particle energy spectra consisting of two power-law regions separated by the so-called knee. Experimental data from the GOES satellites (protons) and ULEIS (all particles) and SIS (H, C, O, Fe ions) instruments are employed. The charge states of the heavy ions are found to be independent of the SEP event magnitude and particle energy (in the interval of 0.3 to 30 MeV/nucleon). 相似文献
9.
10.
Coherent states for the Landau system (planar charged particle moving in a uniform magnetic field) are developed. It is convenient to use these states to describe the circular motion of the charged particle. The results obtained do not depend on gauges. 相似文献
11.
L. A. Manakova 《JETP Letters》2003,77(1):20-24
In the present paper, it is shown that the interaction between classical anharmonic oscillations of a trapped condensate and excited Josephson states corresponding to a large enough initial imbalance of particle number generates their equilibrium bound state. The dynamics of the system are determined by the self-consistent oscillations of the initial imbalance of the particle number and condensate shape. The existence of the bound state implies that the Josephson states can be detected by observing the change of the condensate shape. 相似文献
12.
Pairing vibrational and isospin rotational states are described in different approximations based on particle number and isospin projected, proton-proton, neutron-neutron and proton-neutron pairing wave functions and on the generator coordinate method (GCM). The investigations are performed in models for which an exact group theoretical solution exists. It turns out that a particle number and isospin projection is essential to yield a good approximation to the ground state or isospin yrast state energies. For strong pairing correlations (pairing force constant equal to the single-particle level distance) isospin cranking (-ωTx) yields with particle number projected pairing wave function also good agreement with the exact energies. GCM wave functions generated by particle number and isospin projected BCS functions with different amounts of pairing correlations yield for the lowest T = 0 and T = 2 states energies which are practically indistinguishable from the exact solutions. But even the second and third lowest energies of charge-symmetric states are still very reliable. Thus we conclude that also in realistic cases isospin rotational and pairing vibrational states may be described in the framework of the GCM method with isospin and particle number projected generating wave functions. 相似文献
13.
主要对量子力学一维有限深方势阱中运动粒子的束缚态存在条件进行讨论.通过求解定态薛定谔方程,得到粒子运动满足的超越方程,借助于Mathematica软件求解该超越方程得到粒子的能级结构,对粒子束缚态存在条件进行分析.结果表明,对于在一维有限深对称方势阱中运动的粒子,总会有束缚态的存在,和势阱的宽度、深度及粒子的质量无关.而在半壁有限深势阱中运动的粒子,出现束缚态是有条件的.并且分别给出了在两种势阱中粒子存在多个束缚态需要满足的条件. 相似文献
14.
文章叙述了强子结构的夸克模型的成就和不足,详细介绍了寻找多夸克新粒子态的实验进展. 寻找多夸克新粒子态对中国粒子物理实验学家可能作出世界创新成果是一个良好机遇. 相似文献
15.
A shell model calculation for 47Ti is done. The state with definite angular momenta projected from the prolate and oblate Hartree-Fock states and a few other intrinsic states obtained from these two HF states by 1 particle — 1 hole excitations were used as basis states. The calculated spectrum agrees well with the experimental one. 相似文献
16.
LIANGXian-Ting 《理论物理通讯》2004,42(4):535-538
We calculate the degree of entanglement for some bipartite entangled states of continuous variables.These states include common two-mode squeezed vacuum state, thermal vacuum state of a free single particle (where theh fictitious tilde system is regarded as another particle), and the squeezed vacuum state of two coupling harmonic oscillators.The degree of entanglement for these quantum systems are shown clearly by using the technique of integration within an ordered product of operators. 相似文献
17.
LIANG Xian-Ting 《理论物理通讯》2004,42(10)
We calculate the degree of entanglement for some bipartite entangled states of continuous variables.These states include common two-mode squeezed vacuum state, thermal vacuum state of a free single particle (where the fictitious tilde system is regarded as another particle), and the squeezed vacuum state of two coupling harmonic oscillators.The degree of entanglement for these quantum systems are shown clearly by using the technique of integration within an ordered product of operators. 相似文献
18.
Faithful long-distance quantum teleportation necessitates prior
entanglement distribution between two communicated locations. The
particle carrying on the unknown quantum information is then
combined with one particle of the entangled states for Bell-state
measurements, which leads to a transfer of the original quantum
information onto the other particle of the entangled states. However
in most of the implemented teleportation experiments nowadays, the
Bell-state measurements are performed even before successful
distribution of entanglement. This leads to an instant collapse of
the quantum state for the transmitted particle, which is actually a
single-particle transmission thereafter. Thus the true distance for
quantum teleportation is, in fact, only in a level of meters. In the
present experiment we design a novel scheme which has overcome this
limit by utilizing fiber as quantum memory. A complete quantum
teleportation is achieved upon successful entanglement distribution
over 967 meters in public free space. Active feed-forward control
techniques are developed for real-time transfer of quantum
information. The overall experimental fidelities for teleported
states are better than 89.6%, which signify high-quality
teleportation. 相似文献
19.
Teruhisa S. Komatsu Naoko Nakagawa Shin-Ichi Sasa Hal Tasaki 《Journal of statistical physics》2009,134(2):401-423
Recently a novel concise representation of the probability distribution of heat conducting nonequilibrium steady states was
derived. The representation is valid to the second order in the “degree of nonequilibrium”, and has a very suggestive form
where the effective Hamiltonian is determined by the excess entropy production. Here we extend the representation to a wide
class of nonequilibrium steady states realized in classical mechanical systems where baths (reservoirs) are also defined in
terms of deterministic mechanics. The present extension covers such nonequilibrium steady states with a heat conduction, with
particle flow (maintained either by external field or by particle reservoirs), and under an oscillating external field. We
also simplify the derivation and discuss the corresponding representation to the full order. 相似文献
20.
The asymmetric effects on the escape rates from the stable states x± in the bistable system are analyzed. The results indicate that the multiplicative noise and the additive noise always enhance the particle escape from stable states x± of bistable. However, the asymmetric parameter r enhances the
particle escape from stable state x+, and holds back the particle escape from stable state x-. 相似文献