Change in the Shape of Nuclei in the Chains of Krypton,Strontium, Zirconium,Molybdenum, and Ruthenium Isotopes in the Relativistic-Mean-Field Approximation

Physics of Atomic Nuclei - Changes in the shape of nuclei in the chains of even—even crypton, strontium, zirconium, molybdenum, and ruthenium isotopes are studied on the basis of the...     

Amplitude-N-power squeezing of pure superposition states

The N-order squeezing of the pure superposition states |a,β>_(mn)=a|m> β|n> is studied. We find that there is only N=n—m order squeezing for odd (n—m) except for (n—m)=1(m≥1) , but there are N=n—m order and N=(n—m)/2 order squeezings for even (n—m).     

Systematics of spontaneous-fission barrier heights

Heights of (static) spontaneous-fission barriers of heaviest nuclei are calculated within a macroscopic—microscopic approach. Even—even nuclei with proton numbers Z = 96–120 are considered.     

Regular periodic “explosions” of electron—hole drops under steady-state illumination and microwave heating

DC conductivity measurements on (strained) Ge at 4 K under steady-state illumination show that even in the presence of fairly strong steady-state microwave heating electron—hole drops continue to form, but rather than assuming a steady-state they “explode” periodically. The results are readily explained by — and provide corroboration for — a model by Altukhov.     

微波消解样品ICP-AES同时测定桄榔粉中的锌、铁、钙、镁、锰、铜、钾和钠

用硝酸-过氧化氢(3+2)混合溶液作为消解剂,微波消解法处理桄榔粉样品,采用电感耦合等离子体-原子发射光谱法(ICP-AES)同时测定所得样品溶液中锌、铁、钙、镁、锰、铜、钾和钠的含量。选择谱线(nm)Zn:213.8、Fe:239.5、Ca:317.9、Mg:280.2、Mn:257.6、Cu:224.7、K:766.4、Na:589.5等进行测定。所有元素校准曲线的相关系数均大于0.9997;该方法线性范围(μg.mL-1)Zn、Cu:0.0—2.0,Fe:0.0—10.0,Ca:0.0—60.0,Mg:0.0—40.0,Mn:0.0—5.0,K:0.0—80.0、Na:0.0—20.0;检出限(3Sd,μg.mL-1)为Zn:0.001、Fe:0.025、、Ca:0.020、Mg:0.001、Mn:0.002、Cu:0.006、K:0.069、Na:0.022;样品测定的相对标准偏差(n=6)在0.45%—9.05%之间。用本法测定4个国家标准物质大米粉GBW(E)080684、小麦GBW10011、玉米GBW10012和苹果GBW10019,测定值与标准值相吻合。     

Study of Platinum Isotopes: A Comparison of the Fermion Dynamical Symmetry Model and the Interacting Boson Model

The systematics of the even platinum isotopes are described within the framework of the Fermion Dynamical Symmetry Model. By using a pairing—plus—quadrupole type interactions, we show that the transitional behavior of these isotopes can be effectively accounted for. Good agreement is obtained between theory and data for energy levels, B(E₂) values, electric quadrupole moments, gyromagnetic factors, and the isomer shifts and isotope shifts for ^190—196Pt. The Calculations are also compared with various results obtained from the Interacting Boson Model. Consequently, our numerical calculation show that a very accurate effective SO(6) dynamical sysmmetry exists around ¹⁹⁶Pt, even though the proton-neutron coupled system (SO^π(8)×SP^ν(6)) does not formally contain such a dynamical symmetry in the fermion dynamical symmetry model. Implications of this effective dynamical symmetry are discussed.     

The form factors in (HI,HI') direct reactions

Using a semiclassical theory, we analyze the inelastic transition form factor. We find that: (i) In the strong absorption limit, the Austern-Blair theory is a good approximation to the inelastic form factor — even in highly mismatched reactions, (ii) In weak to moderate absorption, the amplitude of the inelastic form factor oscillates due to overlapping potential resonances. Here the internal part of the form factor can be expressed in a simple form, which may easily be used to analyze heavy-ion inelastic scattering, (iii) In the presence of an isolated resonance, the inelastic form factor is enhanced greatly at the resonance due to multiple reflections inside the potential well.     

Einstein-Podolsky-Rosen entanglement in bad cavity case

This paper explores continuous variable entanglement in four-wave mixing when the atomic relaxation time is comparable to and longer than the cavity relaxation time.In this case the atomic memory is included in the field correlations and the entanglement in the output fields can be significantly enhanced.Einstein-Podolsky-Rosen (EPR) entanglement is achievable even in the bad cavity limit.This shows the EPR entanglement generation without need of good cavity.     

The Eyes of Texas Are Upon You

The first symposium on gravitational collapse and other aspects of relativistic astrophysics (Texas 1, in retrospect) was inspired by one idea—gravitational collapse of massive objects as an energy source—and one observational discovery—the large red shifts of optical counterparts of the quasistellar radiosources (soon quasars, even when radio quiet). Since that time, there has been fierce interplay at Symposia 2–26 between new ideas, new observations (or experiments if you are a physicist) and old ideas given new life. The talk and this paper explore a subset of the interactions. Texas has typically been a broad church, admitting nonstandard ideas and disputed data. Very approximately, half are still part of our universe of discourse.     

Competition between BCS and FFLO States in Magnetic Superconductors in a Cryptoferromagnetic Phase

The possibility of appearance of inhomogeneous superconducting Fulde—Ferrell—Larkin—Ovchinnikov (FFLO) states in magnetic superconductors in a cryptoferromagnetic phase with helical magnetic ordering has been analyzed. The dependence of the critical temperature on the angle between the wave vectors of the spatial modulation of the FFLO state and helical magnetic structure has been calculated within the proposed model. It has been shown that their mutually perpendicular orientation corresponds to the most energetically favorable state. The numerical calculations have also shown the existence of a tricritical point on a line separating the Bardeen—Cooper—Schrieffer and FFLO phases on the phase diagram of states. Furthermore, FFLO states can appear in a magnetic superconductor even at fairly strong exchange fields because of the difference between the effective masses of conduction electrons in different spin subbands and the anisotropy of the Fermi surface.

     

Residual closeness in networks

A new characteristic (residual closeness) which can measure the network resistance is presented. It evaluates closeness after removal of vertices or links, hence two types are considered—vertices and links residual closeness. This characteristic is more sensitive than the well-known measures of vulnerability—it captures the result of actions even if they are small enough not to disconnect the graph. A definition for closeness is modified so it still can be used for unconnected graphs but the calculations are easier.     

Electromechanical-induced antiferroelectricben ferroelectric phase transition in PbLa(Zr,Sn,Ti)O3 ceramic

Antiferroelectric—ferroelectric (AFE—FE) phase transition in ceramic Pb_0.97La_0.02(Zr_0.75Sn_0.136Ti_0.114)O₃ (PLZST) was studied by dielectric spectroscopy as functions of frequency (10²—10⁵ Hz) and pressure (0—500 MPa) under a DC electric field. The hydrostatic pressure-dependent remnant polarization and dielectric constant were measured. The results show that remnant polarization of the metastable rhombohedral ferroelectric PLZST poled ceramic decreases sharply and depoles completely at phase transition under hydrostatic pressure. The dielectric constant undergoes an abrupt jump twice during a load and unload cycle under an electric field. The two abrupt jumps correspond to two phase transitions, FE—AFE and AFE—FE.     

Sequences from number theory for physics,signal processing,and art

In this article I discuss numerical sequences of potential interest to physicists, engineers, and artists. Foremost among these are the maximum-length or “Galois” sequences, based on the prime number 2 and larger primes, which have found wide use in physics, including acoustics, and engineering:

• —the measurement of impulse responses in concert halls, radar echoes from planets (to check the General Theory of Relativity), and travel times in the deep-ocean sound channel (to monitor water temperature and global warming)
• —the spatial diffusion of sound waves, coherent (laser) light, and electromagnetic waves
• —algebraic error-correcting codes (Simplex and Hamming codes)
• —minimizing peak-factors for radar and sonar signals, synthetic speech, and computer music
• —the formation of X-ray images with 2D masks (in X-ray astronomy).

Other sequences include

• —quadratic-residue sequences for the construction of wide-band diffusing reflection-phase-gratings in one and two dimensions
• —the Morse-Thue sequence, the Fibonacci and “rabbit” sequences and their musical potential; and
• —certain self-similar sequences from number theory that engender attractive visual patterns, rhythms, and melodies.

     

Overdamping of coherently driven quantum systems

The phenomenon of overdamping, when frictional forces overwhelm the restoring force of an harmonic oscillator, is well known in classical mechanics. Analogous phenomena occur in time-dependent quantum mechanics when probability loss rates (e.g. photoionization rates) become larger than the characteristic inverse times for coherent excitation (the Rabi frequencies). These results often seem surprising, even for simple two-state quantum systems. We discuss examples of this overdamping phenomenon—when an increase of the loss rate actually produces a slower rate of probability loss and even freezes population—for a number of quantum systems: steady and pulsed two-state excitation, time evolution with adiabatic passage, simple multistate chains, and branched chains of excitation linkage. In each situation there occurs for very large damping, often unexpectedly, phenomena akin to the overdamping of the classical harmonic oscillator.     

原子吸收光谱法测定水泥中的钠、钾、镁和铁

对火焰原子吸收光谱法测定水泥中的钠、钾、镁和铁的方法进行研究。在选定的最佳仪器条件下,测定钠、钾、镁和铁的RSD分别为1.81%、1.05%、2.68%、1.12%。水泥样品中钠、钾、镁和铁的回收率分别为102.0%—104.0%、98.4%—100.4、98.0%—102.0%、98.0%—100.3%。方法操作简单,测试快速,结果准确稳定。     

O(5) symmetry in IBA-1 — the O(6)—U(5) transition region

All IBA-1 hamiltonians whose eigenstates are combinations of states with numbers of d-bosons differing by an even number have O(5) symmetry. Consequences of this symmetry are presented for the O(6)—U(5) transition region for energy levels and electromagnetic transitions. We draw the distinction between evidence for O(6) character of nuclei and that for O(5) symmetry only.     

A Digital Perspective and the Quest for Substrate-Universal Behaviors

Should the Digital Perspective essays collected in these proceedings be viewed more seriously than attempts to play “fundamental theory”—which even in the hands of an Eddington was hard to tell from mythology and numerology? We argue that a nonfrivolous aspect of this Digital Perspective is its heuristic capacity: to help us guess which aspects of our understanding of nature are more “universal,” more robust, more likely to survive theoretical and experimental challenges. Behaviors that are substrate-independent—that can, for instance, thrive well on a digital support, even though they are traditionally imagined as taking place in a continuum—are especially promising candidates.     

Edward Teller, the Hungarian, American and Jew, too

As explained on p. 57 of George Marx’ comprehensive treatiseThe Voice of the Martians [1] (a pun on Leo Szilárd’sVoice of the Dolphins [2]), the titleThe Martians refers to another Szilárd joke, namely to his reply to a question of Fermi’s. In end-of-the-Century parlance, Fermi’s question would be formulated as follows: —With the galaxy presumably full of planetary systems, thereby also of life and thus of intelligence, where are all those extraterrestrials? [3] — to which Szilárd answered —They are among us, but they call themselves Hungarian… — One of these individuals of high intellectual stature, is (“let him be distinguished by a long life” as we would add in such cases by Jewish custom)Edward Teller.     

On current-density algebras,gradient terms and saturation

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.     

OsnN0,±(n=1—6)团簇几何结构与稳定性的理论研究

采用密度泛函理论(DFT)中的B3LYP方法,在Lanl2dz基组水平上对(Os_nN)^0,±(n=1—6)团簇的各种可能构型进行了几何参数全优化,得到了它们的基态构型;并对基态构型的平均结合能(E_b) 、二阶能量差分(Δ₂E_n) 、解离能(E_d)和能隙(E_g)进行了理论研 关键词： nN^{0')" href="#">Os_nN0 (n=1—6)团簇')" href="#">±(n=1—6)团簇 几何结构 稳定性 密度泛函理论}