On Epstein's trajectory model of non-relativistic quantum mechanics

In 1952 Bohm presented a theory about non-relativistic point-particles moving along deterministic trajectories and showed how it reproduces the predictions of standard quantum theory. This theory was actually presented before by de Broglie in 1926, but Bohm's particular formulation of the theory inspired Epstein to come up with a different trajectory model. The aim of this paper is to examine the empirical predictions of this model. It is found that the trajectories in this model are in general very different from those in the de Broglie-Bohm theory. In certain cases they even seem bizarre and rather unphysical. Nevertheless, it is argued that the model seems to reproduce the predictions of standard quantum theory (just as the de Broglie-Bohm theory).Comment: 12 pages, no figures, LaTex; v2 minor improvement

Effect of electronic angular momentum exchange on photoelectron anisotropy following the two-colour ionization of krypton atoms

We present photoelectron energy and angular distributions for resonant two-photon ionization via several low-lying Rydberg states of atomic Kr. The experiments were performed by using synchrotron radiation to pump the Rydberg states and a continuous wave laser to probe them. Photoelectron images, recorded with both linear and circular polarized pump and probe light, were obtained in coincidence with mass-analyzed Kr ions. The photoelectron angular distributions and branching ratios for direct ionization into the Kr+ 2P3/2 and 2P1/2 spin-orbit continua show considerable dependence on the intermediate level, as well as on the polarizations of the pump and probe light. Photoelectron angular distributions were also recorded with several polarization combinations following two-colour excitation of the (2P1/2)5f[5/2]2 autoionizing resonance. These results are compared with the results of recent work on the corresponding autoionizing resonance in atomic Xe

Properties of a Dilute Bose Gas near a Feshbach Resonance

In this paper, properties of a homogeneous Bose gas with a Feshbach resonance are studied in the dilute region at zero temperature. The stationary state contains condensations of atoms and molecules. The ratio of the molecule density to the atom density is $\pi na^3$. There are two types of excitations, molecular excitations and atomic excitations. Atomic excitations are gapless, consistent with the traditional theory of a dilute Bose gas. The molecular excitation energy is finite in the long wavelength limit as observed in recent experiments on $^{85}$Rb. In addition, the decay process of the condensate is studied. The coefficient of the three-body recombination rate is about 140 times larger than that of a Bose gas without a Feshbach resonance, in reasonably good agreement with the experiment on $^{23}$Na.Comment: 11 pages, 1 figure, comparison between the calculated three-body recombination rate and the experimental data for Na system has been adde

Extensional flow affecting shear viscosity: experimental evidence and comparison to models

The effect of extensional flow on apparent shear viscosity has never previously been directly measured nor is it often considered. Here, for the first time, through using a novel flow configuration (two-phase shear response under extensional flow), we have directly measured the effect extensional flow has on the apparent shear viscosity of a viscoelastic polymer solution in a controlled and kinematically mixed manner. We show, via a control transient shear experiment, that the apparent shear viscosity of the solution under mixed deformation depends not only on the shear rate but also on the extension rate and their relative direction: shear thinning being enhanced by parallel and reduced by perpendicular extensional flow, respectively. A 62% reduction in apparent viscosity with parallel extension was seen in this work. We then test the ability of the commonly used Giesekus and Carreau–Yasuda (incorporating generalized shear rate) models to predict the effect of extension rate on apparent shear viscosity against our data. The Giesekus model was found to predict the correct qualitative behavior under both parallel and perpendicular extensional flow, and depending on the fitting parameters, also provided a loosely quantitative agreement. Conversely, the generalized shear rate description does not capture the qualitative behavior, with the most significant errors occurring for perpendicular extension (i.e., expansion) flows. This work emphasizes the rarely noted shortcomings of the latter approach when used for experimental analysis and engineering design when extensional flows are additionally present

Sensitivity of an antineutrino monitor for remote nuclear reactor discovery

Antineutrinos from a nuclear reactor comprise an unshieldable signal, which carries information about the core. A gadolinium-doped, water-based Cherenkov detector has been investigated for detection of reactor antineutrinos for midfield remote reactor monitoring for nonproliferation applications. Two independent reconstruction and analysis pathways have been developed and applied to a number of representative reactor signals to evaluate the sensitivity of a kiloton-scale, gadolinium-doped Cherenkov detector as a remote monitor prototype. The sensitivity of four detector configurations to nine reactor signal combinations was evaluated for a detector situated in Boulby Mine, close to the Boulby Underground Laboratory in the UK. It was found that a 22-m detector with a gadolinium-doped, water-based liquid scintillator fill is sensitive to an approximately 3-GWth reactor at a standoff of approximately 150km within 2 years in the current reactor landscape. A larger detector would be required to achieve a more timely detection or to monitor smaller or more distant reactors

United classification of cosmic gamma-ray bursts and their counterparts

United classification of gamma-ray bursts and their counterparts is established on the basis of measured characteristics: photon energy E and emission duration T. The founded interrelation between the mentioned characteristics of events consists in that, as the energy increases, the duration decreases (and vice versa). The given interrelation reflects the nature of the phenomenon and forms the E-T diagram, which represents a natural classification of all observed events in the energy range from 10E9 to 10E-6 eV and in the corresponding interval of durations from about 10E-2 up to 10E8 s. The proposed classification results in the consequences, which are principal for the theory and practical study of the phenomenon.Comment: Keywords Gamma rays: burst

Resonance Superfluidity: Renormalization of Resonance Scattering Theory

We derive a theory of superfluidity for a dilute Fermi gas that is valid when scattering resonances are present. The treatment of a resonance in many-body atomic physics requires a novel mean-field approach starting from an unconventional microscopic Hamiltonian. The mean-field equations incorporate the microscopic scattering physics, and the solutions to these equations reproduce the energy-dependent scattering properties. This theory describes the high-$T_c$ behavior of the system, and predicts a value of $T_c$ which is a significant fraction of the Fermi temperature. It is shown that this novel mean-field approach does not break down for typical experimental circumstances, even at detunings close to resonance. As an example of the application of our theory we investigate the feasibility for achieving superfluidity in an ultracold gas of fermionic $^6$Li.Comment: 15 pages, 10 figure

Sensitivity of an antineutrino monitor for remote nuclear reactor discovery

Antineutrinos from a nuclear reactor comprise an unshieldable signal which carries information about the core. A gadolinium-doped, water-based Cherenkov detector could detect reactor antineutrinos for mid- to far-field remote reactor monitoring for non-proliferation applications. Two novel and independent reconstruction and analysis pathways have been developed and applied to a number of representative reactor signals to evaluate the sensitivity of a kiloton-scale, gadolinium-doped Cherenkov detector as a remote monitor. The sensitivity of four detector configurations to nine reactor signal combinations was evaluated for a detector situated in Boulby Mine, close to the Boulby Underground Laboratory in the UK. It was found that a 22~m detector with a gadolinium-doped, water-based liquid scintillator fill is sensitive to a ∼3 GWth reactor at a standoff of ∼150 km within two years in the current reactor landscape. A larger detector would be required to achieve a more timely detection or to monitor smaller or more distant reactors

Remote reactor ranging via antineutrino oscillations

Antineutrinos from nuclear reactors can be used for monitoring in the mid- to far-field as part of a non-proliferation toolkit. Antineutrinos are an unshieldable signal and carry information about the reactor core and the distance they travel. Using gadolinium-doped water Cherenkov detectors for this purpose has been previously proposed alongside rate-only analyses. As antineutrinos carry information about their distance of travel in their energy spectrum, the analyses can be extended to a spectral analysis to gain more knowledge about the detected core. Two complementary analyses are used to evaluate the distance between a proposed gadolinium-doped water-based liquid scintillator detector and a detected nuclear reactor. Example cases are shown for a detector in Boulby Mine, near the Boulby Underground Laboratory in the UK, and six reactor sites in the UK and France. The analyses both show strong potential to range reactors, but are limited by the detector design

Coherent States and Modified de Broglie-Bohm Complex Quantum Trajectories

This paper examines the nature of classical correspondence in the case of coherent states at the level of quantum trajectories. We first show that for a harmonic oscillator, the coherent state complex quantum trajectories and the complex classical trajectories are identical to each other. This congruence in the complex plane, not restricted to high quantum numbers alone, illustrates that the harmonic oscillator in a coherent state executes classical motion. The quantum trajectories are those conceived in a modified de Broglie-Bohm scheme and we note that identical classical and quantum trajectories for coherent states are obtained only in the present approach. The study is extended to Gazeau-Klauder and SUSY quantum mechanics-based coherent states of a particle in an infinite potential well and that in a symmetric Poschl-Teller (PT) potential by solving for the trajectories numerically. For the coherent state of the infinite potential well, almost identical classical and quantum trajectories are obtained whereas for the PT potential, though classical trajectories are not regained, a periodic motion results as t --> \infty.Comment: More example