Searcharxiv⌕ Search

arXiv subjects

J. M. LoSecco

Publications and source records attributed to J. M. LoSecco.

31 records · Page 2Linked to original sources
arXiv2002

Imperfect Detectors in Linear Optical Quantum Computers

We discuss the effects of imperfect photon detectors suffering from loss and noise on the reliability of linear optical quantum computers. We show that for a given detector efficiency, there is a maximum achievable success probability, and that increasing the number of ancillary photons and detectors used for one controlled sign flip gate beyond a critical point will decrease the probability that the computer will function correctly. We have also performed simulations of some small logic gates and estimate the efficiency and noise levels required for the linear optical quantum computer to function properly.

quant-ph↗
arXiv2000

(Mis)Understanding the Atmospheric Neutrino Anomaly

The apparent attenuation of muon neutrinos relative to electron neutrinos is a bit too low to be compatible with the most popular values of $Δm^{2}$. Fits to $R(E_ν)$ favor values of $Δm^{2}>0.1$ eV$^{2}$. The fit minimized by the Super Kamioka group in estimating neutrino oscillation parameters neglects systematic errors. The fit is dominated by systematic effects. The data being combined in recent fits may not be compatible since there appear to be significant variations in the properties of the data with time. A simple two component neutrino oscillation with $Δm^{2}$ in the range of 10$^{-3}$ to 10$^{-2}$ eV$^{2}$ seems unable to account for the observations.

hep-ph↗
arXiv2000

Bounds on Extra Dimensions from Binary Pulsars

Evidence for gravitational radiation from binary pulsars places constraints on properties of ``large'' extra dimensions. The size of these extra dimensions must exceed about 37 AU for gravitational radiation to be emitted.

hep-ph↗
arXiv2000

Implementation of a quantum phase gate by the optical Kerr effect

We show that the optical Kerr effect can be used to construct a quantum phase gate. It is well known from quantum nondemolition techniques that, as two photon field modes pass through a Kerr medium, the phase of each mode will be shifted, and the size of the phase shift will depend on the number of photons in both modes. We discuss the Hamiltonian responsible for this effect and show how this can produce an effective photon-photon interaction which corresponds to the quantum phase gate operating on two qubits each of which is represented by the elliptical polarization of one photon field. We discuss decoherence and losses and suggest some methods for dealing with them.

quant-ph↗
arXiv1999

Possible Sources of a Transient Natural Neutrino Flux

Recent observations of variability in the ``atmospheric neutrino'' rate place constraints on possible explanations of the atmospheric neutrino anomaly. Many proposed solutions to the problem are static and can not be adapted to the temporal dependence observed. Nonatmospheric sources may be needed to explain the variations.

hep-ph↗
arXiv1998

$Δm^{2}$ Limits from $R(E_ν)$

A lower bound on $Δm^{2}$ for atmospheric neutrino oscillations can be obtained from the global value of $R$ at a given energy. This bound may be more reliable than one based on the observed isotropy. Some global values of $R$ imply an anisotropy in the neutrino flux that may, or may not be manifest in the observed neutrino interactions. A limit of $Δm^{2}>0.0077$ eV$^{2}$ is easily obtained. Much higher mass scales are implied by the reported energy independence and magnitude of $R$

hep-ph↗
arXiv1998

What the Atmospheric Neutrino Anomaly is Not

The atmospheric neutrino anomaly is the apparent reduction of the $ν_μ/ν_{e}$ ratio observed in underground detectors. It represents either a reduction in the muon neutrino interaction rate or an excess of the electron neutrino interaction rate, or both. Unable to answer the question of ``What else could it be?'' this paper explores a number of alternatives which do not seem to be viable. Various methods to reduce the apparent muon rate or to increase the apparent electron rate are discussed. Perhaps our bias that the interactions are due to neutrinos of atmospheric origin is incorrect. Both of these assumptions need to be confirmed. Efforts to reduce uncertainties in the estimated atmospheric neutrino flux would also help to narrow the possibilities further.

hep-ph↗
arXiv1998

Problems with Atmospheric Neutrino Oscillations

The neutrino oscillation hypothesis does a poor job of representing the atmospheric neutrino anomaly. The anomaly is observed over 4 decades in path length and at least a factor of 30 in energy. This restricts the potential oscillation solutions to those with large amplitudes and mixing mass differences that are ruled out by other observations. The $Δm^{2}$ region in the range $10^{-4} - 10^{-2}$ leads to inconsistencies within the atmospheric neutrino data itself. The observed value of $R$ seems to be incompatible with the $Δm^{2}$ implied by recent results

hep-ph↗
arXiv1997

Bounds on Dark Matter from the ``Atmospheric Neutrino Anomaly''

Bounds are derived on the cross section, flux and energy density of new particles that may be responsible for the atmospheric neutrino anomaly. $4.6 \times 10^{-45} cm^2 < σ<2.4 \times 10^{-34} cm^2$ Decay of primordial homogeneous dark matter can be excluded.

hep-ph↗
arXiv1995

Search for Exotic Mesons in pi- P Interactions at 18 GeV/c

The recent search for non $q \bar{q}$ mesons in $π^{-}p$ interactions at Brookhaven National Laboratory is summarized. Many final states such as $ηπ$, $η' π^{-}$, $a_{0} π$, $f_{1} π$, $a_{2} π$, $b_{1} π$, which are favored decay modes of exotics, are under investigation.

hep-ex↗
arXiv1994

Studying the Quark Antiquark Force with Inelastic Pion Electron Scattering

The concept of studying the internal structure of mesons is explored. Mesons, which are in principle two body quark antiquark interactions, may be much easier to understand than the nucleon. Measurements of the inelastic form factors to specific final states may permit careful direct studies of various components of the strong force. For example by looking at vector meson final states the spin flip amplitude can be isolated. Technical difficulties involved in a realistic experiment are examined. Experiments to some final states such as $ρ$, $K^*$ and $a_{0}$ are practical today.

hep-ph↗