Condensation phenomena in gravity

Gravity can play a role in critical phenomena. Topological singularities induce ground state degeneracy and break the continuum symmetry of the vacuum. They also generate momenta oscillations about an average momentum and a positive gravitational susceptibility. Gravitational analogues of the laws of Curie and Bloch have been found for a one-dimensional model. The critical temperature for a change in phase from bound to unbound vortices has also been calculated in a XY-model.

Quantum Interference of Force

We show that a quantum particle subjected to a positive force in one path of a Mach-Zehnder interferometer and a null force in the other path may receive a negative average momentum transfer when it leaves the interferometer by a particular exit. In this scenario, an ensemble of particles may receive an average momentum in the opposite direction of the applied force due to quantum interference, a behavior with no classical analogue. We discuss some experimental schemes that could verify the effect with current technology, with electrons or neutrons in Mach-Zehnder interferometers in free space and with atoms from a Bose-Einstein condensate.

A Model of a Quantum Particle in a Quantum Environment: A Numerical Study

We define and investigate, via numerical analysis, a one dimensional toy-model of a cloud chamber. An energetic quantum particle, whose initial state is a superposition of two identical wave packets with opposite average momentum, interacts during its evolution and exchanges (small amounts of) energy with an array of localized spins. Triggered by the interaction with the environment, the initial superposition state turns into an incoherent sum of two states describing the following situation: or the particle is going to the left and a large number of spins on the left side changed their states, or the same is happening on the right side. This evolution is reminiscent of what happens in a cloud chamber where a quantum particle, emitted as a spherical wave by a radioactive source, marks its passage inside a supersaturated vapour-chamber in the form of a sequence of small liquid bubbles arranging themselves around a possible classical trajectory of the particle.

Target Single-Spin Asymmetry in Inclusive Hadron Production

We present the first measurement of target single-spin asymmetries (AN) in the inclusive hadron production reaction, e+3 He ↑ →h+X, using a transversely polarized 3 He target at an electron-nucleon center-of-mass energy [Formula: see text] GeV. The experiment was conducted at Jefferson Lab in Hall A using a 5.9-GeV electron beam. Several types of hadrons (π±, K± and proton) were detected with an average momentum 〈Ph〉 = 2.35 GeV/c, and an average transverse momentum 〈pT〉 = 0.64 GeV/c. The observed asymmetry strongly depends on the type of hadron. A positive asymmetry is observed for π+ and K+. A negative asymmetry is observed for π-. The π+ and π- asymmetries measured for the 3 He target and extracted the "effective- neutron" SSA. Amazingly, we found that the ratio of our observed SSA between π+ and π- productions closely resemble the ratio of up- to down-quark's contributions to neutron's anomalous magnetic moment.

Electron Mobility Model for Tensile Strained-Si(101)

Nowadays, the strained-Si technology has been used to maintain the momentum of semiconductor scaling due to its enhancement performance result from the higher mobility. In this paper, the influence of ionizing impurity scattering, acoustic phonon scattering and intervalley scattering to strained-Si (101) material is discussed.In addition, a calculation of the electron mobility in Strained-Si (101) material is made using the average momentum relaxation time method described in Ref [1]. The results show that the electron mobility increases gradually for both [001] and [100] orientations while for [010] orientation increases rapidly with the increasing Ge fraction x.[1]

Light nuclei formation in 12CC collisions at 4.2A GeV/c

Some properties: average multiplicity, average momentum and average transverse momentum of light nuclei (without identification), produced in 12 CC collisions at 4.2 A GeV /c are studied as a function of centrality. An unexpected change in the behavior of these properties is observed within the same region of centrality, where the multiplicity of the produced light nuclei is increased. These measurements are compared with models, Cascade and Fritiof predictions, which fail to account for the observed effect. It is suggested that the inclusion of nuclear coalescence effect may explain the difference between the measurements and the predictions.