A geometrical interpretation of the Pauli exclusion principle in classical field theory

It is shown that classical Dirac fields with the same couplings obey the Pauli exclusion principle in the following sense: If at a certain time two Dirac fields are in different states, they can never reach the same one. This is geometrically interpreted as analogous to the impossibility of crossing of trajectories in the phase space of a dynamical system. An application is made to a model in which extended particles are represented as solitary waves of a set of several fundamental, confined nonlinear Dirac fields, with the result that the same mechanism accounts both for fermion and boson behaviors.     

用泡利原理估算自由电子的比热和电导率

类似于估算自由电子顺磁磁化率，用泡利原理估算了自由电子的比热和电导率，其物理图像清楚，简单易懂。     

Lorentz ionization of atoms in a strong magnetic field

Lorentz ionization emerges due to the motion of atoms or ions in a strong magnetic field. We use the semiclassical approximation to calculate the probability w _L of Lorentz ionization. We also find the stabilization factor S, which takes into account the reduction by the magnetic field of the probability of ionization decay of the bound s state. We estimate the probabilities w _L in magnetic-cumulation experiments and in astrophysics. We also qualitatively examine the dynamics of the magnetic cumulation process with allowance for the conductivity of the shell. Finally, we discuss a paradox related to the use of the quasistationary solution at the shell expansion stage. Zh. éksp. Teor. Fiz. 115, 1642–1663 (May 1999)     

Effect of the Pauli exclusion principle on the potential of nucleus-nucleus interaction

The dependence of the potentials of nucleus-nucleus interaction on taking into account the antisymmetrization of nucleons and the contribution of the nucleon kinetic energy to the potential is studied within approaches based on the energy-density functional, double-folding model, and the two-center shell model. It is shown that the contribution of the nucleon kinetic energy in colliding nuclei leads to the appearance of a significant core at short distances between the nuclei involved.     

Testing the Pauli exclusion principle with the NEMO-2 detector

The Pauli Exclusion Principle (PEP) was tested with the NEMO-2 detector. Limits at the 90% C.L. on the violation of PEP for p-shell nucleons in ¹²C were obtained. Specifically, transitions to the fully occupied 1s _1/2-shell yielded a limit of 4.2 · 10²⁴ y for the process with emission of a γ-quantum. Similarly limits of 3.1 · 10²⁴ y for β⁻ and 2.6 · 10²⁴ y for β⁺ Pauli-forbidden transitions of ¹²C →¹²?¹²B) are reported here. Received: 25 August 1999     

Complete state counting for Gentile's generalization of the Pauli exclusion principle

In the present work, we perform the complete state counting for Gentile's approach to the generalized Pauli exclusion principle (GPEP), which has been lacking in the literature. We count the total number of ways to allocate n identical particles occupying a group of g states with up to q particles in each state, in order to derive an exact expression for the statistical weight. Our obtained expression for the statistical weight gives the fermionic one for q=1; and for q>1, it tends fast to a bosonic weight. Moreover, we perform a numerical comparison between our state counting and Wu's (corresponding to the Haldane-Wu's formulation of the GPEP), which implies that Gentile's formulation gives rise to more boson-like behavior while Haldane-Wu's approach to more fermion-like behavior; this difference lies on the fact that each formulation has its own state-occupation rules on which correlation plays a key role.     

Influence of quantum transitions in the continuum on ionization of atoms in strong fields

The tight-binding method is used to analyze the ionization of a hydrogenlike atom by an intense monochromatic laser field. The orthogonal and normalized basis in which the solution of the time-dependent Schrödinger equation is expanded contains unperturbed wave functions of the discrete spectrum and generalized Coulomb wave functions of the continuum. In the solution of the coupled equations we make use of the fact that the bound-free and free-free transitions are efficient in different regions of complex time. Simplified equations are constructed and investigated. Results of calculations for ionization of a hydrogen atom from its ground state and of the energy distribution of the electrons in strong and superstrong linearly polarized fields are presented. It is shown that in this case the ground state decays completely, and free-free transitions play a defining role in the dynamics of the process. It is established that the total probability of population of the upper Rydberg states abutting the continuum does not exceed 0.05. The range of applicability of the approach is discussed. A comparison with numerical results obtained by other authors is given.     

Effect of electron exchange on atomic ionization in a strong electric field

Hartree-Fock atom in a strong electric static field is considered. It is demonstrated that exchange between outer and inner electrons, taken into account by the so-called Fock term affects strongly the long-range behavior of the inner electron wave function. As a result, it dramatically increases its probability to be ionized. A simple model is analyzed demonstrating that the decay probability, compared to the case of a local (Har-tree) atomic potential, increases by many orders of magnitude. As a result of such increase, the ratio of inner to outer electrons ionization probability became not too small. It is essential that the effect of exchange upon probability of inner electron ionization by strong electric field is proportional to the square of the number of outer electrons. It signals that in clusters the inner electron ionization by strong field, the very fact of which is manifested by e.g. high energy quanta emission, has to be essentially increased as compared to this process in gaseous atomic objects.     

Relativistic theory of tunnel and multiphoton ionization of atoms in a strong laser field

Relativistic generalization is developed for the semiclassical theory of tunnel and multiphoton ionization of atoms and ions in the field of an intense electromagnetic wave (Keldysh theory). The cases of linear, circular, and elliptic polarizations of radiation are considered. For arbitrary values of the adiabaticity parameter γ, the exponential factor in the ionization rate for a relativistic bound state is calculated. For low-frequency laser radiation , an asymptotically exact formula for the tunnel ionization rate for the atomic s level is obtained including the Coulomb, spin, and adiabatic corrections and the preexponential factor. The ionization rate for the ground level of a hydrogen-like atom (ion) with Z ? 100 is calculated as a function of the laser radiation intensity. The range of applicability is determined for nonrelativistic ionization theory. The imaginary time method is used in the calculations.     

Influence of the laser field polarization on the electron impact ionization of hydrogen

The triple differential cross-sections for the ionization of hydrogen by electron impact in the presence of a laser field have been calculated in the coplanar asymmetric geometry by using the first Born approximation and the symmetric geometry by using the Coulomb-Born approximation at an incident electron energy of 250 eV. The variation of the triple differential cross-sections, for fixed values of the angles of scattering and ejection, is studied as a function of the linear polarization of the laser field. The changes are quite amenable to experimental investigation.     

New experimental limits on violations of the Pauli exclusion principle obtained with the Borexino Counting Test Facility

The Pauli exclusion principle (PEP) has been tested for nucleons (n,p) in and nuclei, using the results of background measurements with the prototype of the Borexino detector, the Counting Test Facility (CTF). The approach consisted of a search for , n, p and/or s emitted in a non-Paulian transition of 1P- shell nucleons to the filled 1S _1/2 shell in nuclei. Similarly, the Pauli-forbidden decay processes were searched for. Due to the extremely low background and the large mass (4.2 tons) of the CTF detector, the following most stringent up-to-date experimental bounds on PEP violating transitions of nucleons have been established: , , , , and , all at C.L.Received: 18 June 2004, Published online: 1 October 2004PACS: 11.30.-j, 24.80. + y, 23.20.-g, 27.20. + nG. Bellini: SpokesmanL. Cadonati: Now at Massachusetts Institute of Technology, NW17-161, 175 Albany St. Cambridge, MA 02139O. Dadoun: Marie Curie fellowship at LNGS Correspondence to: A. Derbin. On leave of absence from St. Petersburg Nuclear Physics Inst. - Gatchina, RussiaM. Deutsch: DeceasedR. Ford: No w at Sudbury Neutrino Observatory, INCO Creighton Mine, P.O.Box 159 Lively, Ontario, Canada, P3Y 1M3B. Freudiger: Marie Curie fellowship at LNGS. Now at Institute for Nuclear Physics, Forschungszentrum Karlsruhe, Postfach 3640, 76021 KarlsruheS. Gazzana: GLIMOSV.V. Kobychev: Now at Institute for Nuclear Research, Prospekt Nauki 47, MSP 03680, Kiev, UkraineG. Korga: On leave of absence from KFKI-RMKI, Konkoly Thege ut 29-33 H-1121 Budapest, HungaryC. Lendvai: Marie Curie fellowship at LNGSP. Lombardi: Detector installation managerA. Martemianov: DeceasedV. Muratova: On leave of absence from St. Petersburg Nuclear Physics Inst. - Gatchina, RussiaL. Niedermeier: Marie Curie fellowship at LNGSL. Papp: On leave of absence from KFKI-RMKI, Konkoly Thege ut 29-33 H-1121 Budapest, HungaryR.S. Raghavan: Present Address: Department of Physics, Virginia Polytechnic Institute and State University, Blacksburg VA 24061G. Ranucci: Project managerC. Salvo: Operational manager Correspondence to: O. SmirnovA. Sonnenschein: Center for Cosmological Physics, University of Chicago, 933 E.56^th St., Chicago, IL 60637     

Influence of cesium atoms on the field electron emission from multi-walled carbon nanotubes

It has been shown that the deposition of cesium atoms on multi-wall carbon nanotubes abruptly increases the current of the field electron emission, decreases the threshold electric field by a factor of three (to 0.8 V/m), and decreases the work function to 2.1–2.3 eV. It has been found that the flowing of the large emission current I ≥ 2 × 10^?6 A leads to a change in the current-voltage characteristics and a decrease in the emission current. This effect has been explained by escape of cesium atoms from the tips of most nanotubes into the nanotube depth due to desorption or intercalation. At the same time, the low work function is retained for some nanotubes, probably, due to the stronger bonding of Cs atoms with these nanotubes.     

Influence of Coulomb force between two electrons on double ionization of He-like atoms

In strong-field double ionization,two electrons are ionized by intense laser field.These two electrons move in the laser field and the state is described by a Coulomb-Volkov state,where the repulsive Coulomb state describes the relative motion of the two electrons and the Volkov state describes the center-of-mass motion of the two electrons in the laser field.In the frame of scattering theory,we derive a simple analytical formula of the double ionization of He-like atoms.The effect of the Coulomb force between two electrons on the double ionization process is discussed.Numerical studies disclose that the Coulomb force enhances the ionization rate of high-energy electrons but suppresses the ionization rate of the lowest-energy electrons.