How do Neutrinos Propagate ? - Wave-Packet Treatment of Neutrino Oscillation

The wave-packet treatment of neutrino oscillation developed previously is extended to the case in which momentum distribution functions are taken to be a Gaussian form with both central values and dispersions depending on the mass eigenstates of the neutrinos. It is shown among other things that the velocity of the neutrino wave packets does not in general agree with what one would expect classically and that relativistic neutrinos emitted from pions nevertheless do follow, to a good approximation, the classical trajectory.Comment: 13 page. No figure. Typeset using PTPTeX.st

Digital Switching in the Quantum Domain

In this paper, we present an architecture and implementation algorithm such that digital data can be switched in the quantum domain. First we define the connection digraph which can be used to describe the behavior of a switch at a given time, then we show how a connection digraph can be implemented using elementary quantum gates. The proposed mechanism supports unicasting as well as multicasting, and is strict-sense non-blocking. It can be applied to perform either circuit switching or packet switching. Compared with a traditional space or time domain switch, the proposed switching mechanism is more scalable. Assuming an n-by-n quantum switch, the space consumption grows linearly, i.e. O(n), while the time complexity is O(1) for unicasting, and O(log n) for multicasting. Based on these advantages, a high throughput switching device can be built simply by increasing the number of I/O ports.Comment: 24 pages, 16 figures, LaTe

CP,T and/or CPT Violations in the K0-K0bar System --Implications of the KTeV,NA48 and CPLEAR Results

Possible violation of CP, T and/or CPT symmetries in the \ko-\kob system is studied from a phenomenological point of view. For this purpose, we first introduce parameters which represent violation of these symmetries in mixing parameters and decay amplitudes in a convenient and well-defined way and, treating these parameters as small, derive formulas which relate them to the experimentally measured quantities. We then perform numerical analyses, with the aid of the Bell-Steinberger relation, to derive constraints to these symmetry-violating parameters, firstly paying particular attention to the results reported by KTeV Collaboration and NA48 Collaboration, and then with the results reported by CPLEAR Collaboration as well taken into account. A case study, in which either CPT symmetry or T symmetry is assumed, is also carried out. It is demonstrated that CP and T symmetries are violated definitively at the level of 10^{-4} in $2\pi$ decays and presumably at the level of 10^{-3} in the \ko-\kob mixing, and that the Bell-Steinberger relation helps us to establish CP and T violations being definitively present in the \ko-\kob mixing and to test CPT symmetry to a level of 10^{-4} ~ 10^{-5}.Comment: 21 pages, 1 figure

A group-velocity criterion for breakdown of vortex flow: An application to measured inlet profiles

Vortex flows exhibiting breakdown in a slightly divergent duct were measured. The slowly varying vortex flow field downstream of the entrance and upstream of the breakdown region is obtained numerically by using the inviscid quasi-cylindrical approximation. In these calculations, the Faler and Lebovich's experimental data were used as the starting conditions at the entrance of the duct. The group velocity of wave propagation for the axisymmetric mode (n = 0) and the asymmetric modes (n = + or - 1 and n = + or - 2) are calculated for the entrance conditions. For the theoretically predicted slowly varying flow field downstream of the entrance, the wave characteristics of the n = 0 and n = + or - 1 modes are presented. It was concluded that the flows which subsequently undergo vortex breakdown are all predicted to be supercritical and stable to infinitesimal inviscid disturbances, including the axially symmetric as well as the nonsymmetric perturbations

An examination of a group-velocity criterion for the breakdown of an idealized vortex flow

The phenomenon of vortex breakdown is believed to be associated with a finite amplitude wave that has become trapped at the critical or breakdown location. The conditions at which the propagating waves become trapped at a certain axial location were examined by use of a group-velocity criterion implied by Landahl's general theory of wave trapping. An ideal vortex having constant vorticity and uniform axial velocity at the inlet of a slowly diverging duct was studied. The linear wave propagation analysis is applied to the base flow at several axial stations for several values of the ratio of swirl velocity to axial velocity at the inlet of the divergent duct, assuming a locally parallel flow. The dipsersion relations and hence the group velocities of both the symmetric (n = 0) and asymmetric modes (n = + or - 1) were investigated. The existence of a critical state in the flow (at which the group velocity vanishes), and its relationship to the stagnation point on the axis of the duct and to the occurrence of an irregular singularity in the equations governing wave propagation in the flow field are discussed

Addendum to the test of CP violation in tau decay

We discuss the test of CP and CPT violation in \tau decay without using the polarized electron beam by comparing partial fractions of \tau^- and \tau^+ decay into channels with strong final state interactions. For example, \Gamma(\tau^-\rarrow \pi^-+\pi^0+\nu) \ne \Gamma(\tau^+\rarrow \pi^++\pi^0+\nu) signifies violation of CP. The optimum energy to investigatge CP violation in \tau decay is discussed. We conclude that this energy is a few MeV below \psi(2s) in order to avoid the charm contribution and over abundance of hadrons at the \psi(2s) peak