8,513 research outputs found
A New Algebraic Structure of Finite Quantum Systems and the Modified Bessel Functions
In this paper we present a new algebraic structure (a super hyperbolic system
in our terminology) for finite quantum systems, which is a generalization of
the usual one in the two-level system.
It fits into the so-called generalized Pauli matrices, so they play an
important role in the theory. Some deep relation to the modified Bessel
functions of integer order is pointed out.
By taking a skillful limit finite quantum systems become quantum mechanics on
the circle developed by Ohnuki and Kitakado.Comment: Latex ; 14 pages ; no figure ; minor changes. To appear in
International Journal of Geometric Methods in Modern Physics, (Vo.4, No.7),
200
Flow Equations for Uplifting Half-Flat to Spin(7) Manifolds
In this short supplement to [1], we discuss the uplift of half-flat six-folds
to Spin(7) eight-folds by fibration of the former over a product of two
intervals. We show that the same can be done in two ways - one, such that the
required Spin(7) eight-fold is a double G_2 seven-fold fibration over an
interval, the G_2 seven-fold itself being the half-flat six-fold fibered over
the other interval, and second, by simply considering the fibration of the
half-flat six-fold over a product of two intervals. The flow equations one gets
are an obvious generalization of the Hitchin's flow equations (to obtain
seven-folds of G_2 holonomy from half-flat six-folds [2]). We explicitly show
the uplift of the Iwasawa using both methods, thereby proposing the form of the
new Spin(7) metrics. We give a plausibility argument ruling out the uplift of
the Iwasawa manifold to a Spin(7) eight fold at the "edge", using the second
method. For eight-folds of the type , being a
seven-fold of SU(3) structure, we motivate the possibility of including
elliptic functions into the "shape deformation" functions of seven-folds of
SU(3) structure of [1] via some connections between elliptic functions, the
Heisenberg group, theta functions, the already known -brane metric [3] and
hyper-K\"{a}hler metrics obtained in twistor spaces by deformations of
Atiyah-Hitchin manifolds by a Legendre transform in [4].Comment: 12 pages, LaTeX; v3: (JMP) journal version which includes clarifying
remarks related to connection between Spin(7)-folds and SU(3)structur
Static and Dynamic Properties of Trapped Fermionic Tonks-Girardeau Gases
We investigate some exact static and dynamic properties of one-dimensional
fermionic Tonks-Girardeau gases in tight de Broglie waveguides with attractive
p-wave interactions induced by a Feshbach resonance. A closed form solution for
the one-body density matrix for harmonic trapping is analyzed in terms of its
natural orbitals, with the surprising result that for odd, but not for even,
numbers of fermions the maximally occupied natural orbital coincides with the
ground harmonic oscillator orbital and has the maximally allowed fermionic
occupancy of unity. The exact dynamics of the trapped gas following turnoff of
the p-wave interactions are explored.Comment: 4 pages, 2 figures, submitted to PR
Static, massive fields and vacuum polarization potential in Rindler space
In Rindler space, we determine in terms of special functions the expression
of the static, massive scalar or vector field generated by a point source. We
find also an explicit integral expression of the induced electrostatic
potential resulting from the vacuum polarization due to an electric charge at
rest in the Rindler coordinates. For a weak acceleration, we give then an
approximate expression in the Fermi coordinates associated with the uniformly
accelerated observer.Comment: 11 pages, latex, no figure
The Effects of Prehydration on Cement Performance
This study investigated the effects of cement prehydration on cement’s engineering properties. Anhydrous cement was exposed over a saturated KCl solution to maintain 85% RH, for 7 and 28 days. Mortar and cement pastes were tested for strength, workability and setting time, with sample analysis by XRD and DTA. Results showed a decreased reactivity of the prehydrated cements resulting in reduced strength and increased setting times. We propose that this may be due to an upset of the sulphate balance in the cement upon prehydration
On the type species of Aubignyna and a description of A. hamblensis, a new microforaminifer from temperate shallow waters
The genus Aubignyna Margerel, 1970 (type A. mariei) was originally described from the upper Pliocene of NW France. Examination and re-illustration of topotypes of A. mariei Margerel, 1970, the holotype of Buccella planidorso Atkinson, 1969 (from the Recent of Cardigan Bay, Wales) and syntypes of Rotalia perlucida Heron-Allen and Earland, 1913 (from the Clare Island Survey, western Ireland) shows them to be conspecific. Consequently, the type-species of Aubignyna becomes R. perlucida, for which a lectotype is chosen. A new species of microforaminifera formally described here is assigned to Aubignyna and shown to occur in a wide range of intertidal - shallow subtidal, brackish - normal marine estuaries and lagoons in Europe and North America
Gravity-induced resonances in a rotating trap
It is shown that in an anisotropic harmonic trap that rotates with the
properly chosen rotation rate, the force of gravity leads to a resonant
behavior. Full analysis of the dynamics in an anisotropic, rotating trap in 3D
is presented and several regions of stability are identified. On resonance, the
oscillation amplitude of a single particle, or of the center of mass of a
many-particle system (for example, BEC), grows linearly with time and all
particles are expelled from the trap. The resonances can only occur when the
rotation axis is tilted away from the vertical position. The positions of the
resonances (there are always two of them) do not depend on the mass but only on
the characteristic frequencies of the trap and on the direction of the angular
velocity of rotation.Comment: 10 pages, 12 figures, to appear in Physical Review
Modular symmetry and temperature flow of conductivities in quantum Hall systems with varying Zeeman energy
The behaviour of the critical point between quantum Hall plateaux, as the
Zeeman energy is varied, is analysed using modular symmetry of the Hall
conductivities following from the law of corresponding states. Flow diagrams
for the conductivities as a function of temperature, with the magnetic field
fixed, are constructed for different Zeeman energies, for samples with
particle-hole symmetry.Comment: 15 pages, 13 figure
The Passagassawakeag Rail Trail, Belfast, Maine
Maine Geological Survey, Geologic Facts and Localities, Circular GFL-224https://digitalmaine.com/mgs_publications/1515/thumbnail.jp
Improvising Linguistic Style: Social and Affective Bases for Agent Personality
This paper introduces Linguistic Style Improvisation, a theory and set of
algorithms for improvisation of spoken utterances by artificial agents, with
applications to interactive story and dialogue systems. We argue that
linguistic style is a key aspect of character, and show how speech act
representations common in AI can provide abstract representations from which
computer characters can improvise. We show that the mechanisms proposed
introduce the possibility of socially oriented agents, meet the requirements
that lifelike characters be believable, and satisfy particular criteria for
improvisation proposed by Hayes-Roth.Comment: 10 pages, uses aaai.sty, lingmacros.sty, psfig.st
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