7,032 research outputs found
Reaching the continuum limit in lattice gauge theory - without a computer
The scaling slope of the anti-symmetric mass gap M of compact U(1)_{2+1}
lattice gauge theory is obtained analytically in the Hamiltonian formalism
using the plaquette expansion. Based on the first four moments of the
Hamiltonian with respect to a one-plaquette mean field state the results
demonstrate clear scaling of M at and beyond the transition from strong to weak
coupling. The scaling parameters determined agree well with the range of
numerical determinations available.Comment: 4 pages, 2 figure
Adiabatic & non-adiabatic perturbation theory for coherence vector description of neutrino oscillations
The standard wave function approach for the treatment of neutrino
oscillations fails in situations where quantum ensembles at a finite
temperature with or without an interacting background plasma are encountered.
As a first step to treat such phenomena in a novel way, we propose a unified
approach to both adiabatic and non-adiabatic two-flavor oscillations in
neutrino ensembles with finite temperature and generic (e.g. matter)
potentials. Neglecting effects of ensemble decoherence for now we study the
evolution of a neutrino ensemble governed by the associated Quantum Kinetic
Equations, which apply to systems with finite temperature. The Quantum Kinetic
Equations are solved formally using the Magnus expansion and it is shown that a
convenient choice of the quantum mechanical picture (e.g. the interaction
picture) reveals suitable parameters to characterize the physics of the
underlying system (e.g. an effective oscillation length). It is understood that
this method also provides a promising starting point for the treatment of the
more general case in which decoherence is taken into account.Comment: 14 page
Analytic Solution for the Ground State Energy of the Extensive Many-Body Problem
A closed form expression for the ground state energy density of the general
extensive many-body problem is given in terms of the Lanczos tri-diagonal form
of the Hamiltonian. Given the general expressions of the diagonal and
off-diagonal elements of the Hamiltonian Lanczos matrix, and
, asymptotic forms and can be defined in
terms of a new parameter ( is the Lanczos iteration and is
the size of the system). By application of theorems on the zeros of orthogonal
polynomials we find the ground-state energy density in the bulk limit to be
given in general by .Comment: 10 pages REVTex3.0, 3 PS figure
Neutrino-antineutrino oscillations as a possible solution for the LSND and MiniBooNE anomalies?
We investigate resonance structures in CPT and Lorentz symmetry violating
neutrino-antineutrino oscillations in a two generation framework. We work with
four non-zero CPT-violating parameters that allow for resonant enhancements in
neutrino-antineutrino oscillation phenomena in vacuo which are suitably
described in terms of charge conjugation eigenstates of the system. We study
the relation between the flavor, charge conjugation and mass eigenbasis of
neutrino-antineutrino oscillations and examine the interplay between the
available CPT-violating parameter space and possible resonance structures.
Eventually we remark on the consequences of such scenarios for neutrino
oscillation experiments, namely possible solutions for the LSND and MiniBooNE
anomalies.Comment: 14 pages, 3 figure
Explaining LSND and MiniBooNE using altered neutrino dispersion relations
We investigate the possibility to explain the MiniBooNE anomaly by CPT and
Lorentz symmetry violating neutrino-antineutrino oscillations in a two
generation framework. We work with four non-zero CPT-violating parameters that
allow for resonant enhancements in neutrino-antineutrino oscillation phenomena
in vacuo which are suitably described in terms of charge conjugation
eigenstates of the system. We study the relation between the flavor, charge
conjugation and mass eigenbasis of neutrino-antineutrino oscillations and
examine the interplay between the available CPT-violating parameter space and
possible resonance structures.Comment: 3 pages, 1 figure, Proceedings for Erice 2009 Neutrinos in Cosmology,
in Astro-, Particle- and Nuclear Physic
Optimising Matrix Product State Simulations of Shor's Algorithm
We detail techniques to optimise high-level classical simulations of Shor's
quantum factoring algorithm. Chief among these is to examine the entangling
properties of the circuit and to effectively map it across the one-dimensional
structure of a matrix product state. Compared to previous approaches whose
space requirements depend on , the solution to the underlying order-finding
problem of Shor's algorithm, our approach depends on its factors. We performed
a matrix product state simulation of a 60-qubit instance of Shor's algorithm
that would otherwise be infeasible to complete without an optimised
entanglement mapping.Comment: 8 pages, 2 figures, 2 tables. v2 using PDFLaTeX compiler. v3 to
include extra references. v4 for publication in Quantu
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