12,552 research outputs found
Reciprocal relativity of noninertial frames: quantum mechanics
Noninertial transformations on time-position-momentum-energy space {t,q,p,e}
with invariant Born-Green metric ds^2=-dt^2+dq^2/c^2+(1/b^2)(dp^2-de^2/c^2) and
the symplectic metric -de/\dt+dp/\dq are studied. This U(1,3) group of
transformations contains the Lorentz group as the inertial special case. In the
limit of small forces and velocities, it reduces to the expected Hamilton
transformations leaving invariant the symplectic metric and the nonrelativistic
line element ds^2=dt^2. The U(1,3) transformations bound relative velocities by
c and relative forces by b. Spacetime is no longer an invariant subspace but is
relative to noninertial observer frames. Born was lead to the metric by a
concept of reciprocity between position and momentum degrees of freedom and for
this reason we call this reciprocal relativity.
For large b, such effects will almost certainly only manifest in a quantum
regime. Wigner showed that special relativistic quantum mechanics follows from
the projective representations of the inhomogeneous Lorentz group. Projective
representations of a Lie group are equivalent to the unitary reprentations of
its central extension. The same method of projective representations of the
inhomogeneous U(1,3) group is used to define the quantum theory in the
noninertial case. The central extension of the inhomogeneous U(1,3) group is
the cover of the quaplectic group Q(1,3)=U(1,3)*s H(4). H(4) is the
Weyl-Heisenberg group. A set of second order wave equations results from the
representations of the Casimir operators
Electrostatic propulsion system with a direct nuclear electrogenerator Patent
Nuclear electric generator for accelerating charged propellant particles in electrostatic propulsion syste
Unexploited Connections Between Intra- and Inter-temporal Allocation
This paper shows that a power utility specification of preferences over total expenditure (ie. CRRA preferences) implies that intratemporal demands are in the PIGL/PIGLOG class. This class generates (at most) rank two demand systems and we can test the validity of power utility on cross-section data. Further, if we maintain the assumption of power utility, and within period preferences are not homothetic, then the intertemporal preference parameter is identified by the curvature of Engel curves. Under the power utility assumption, neither Euler equation estimation nor structural consumption function estimation is necessary to identify the power parameter. In our empirical work, we use demand data to estimate the power utility parameter and to test the assumption of the power utility representation. We find estimates of the power parameter larger than obtained from Euler equation estimation, but we reject the power specification of within period utility.elasticity of intertemporal substitution, Euler equation estimation, demand systems
Borrowing Constraints, the Cost of Precautionary Saving, and Unemployment Insurance
Job losers exhibit significant heterogeneity in wealth holdings and in the marginal propensity to consume transitory income. We consider potential sources of this heterogeneity, whether (some of) the unemployed face borrowing constraints, and the implications of this heterogeneity for unemployment insurance. We show theoretically how the optimal benefit can depend significantly on borrowing constraints, and on other (non-precautionary) savings motives. We report empirical evidence that (i) a quarter of job losers cannot borrow for current consumption, (ii) this constraint is binding for a much smaller fraction, and (iii) that "excess sensitivity" is not limited to the constrained.unemployment, savings, credit constraints, life-cycle, consumption, unemployment insurance
Borrowing Constraints, the Cost of Precautionary Saving, and Unemployment Insurance
Job losers exhibit significant heterogeneity in wealth holdings and in the marginal propensity to consume transitory income. We consider potential sources of this heterogeneity, whether (some of) the unemployed face borrowing constraints, and the implications of this heterogeneity for unemployment insurance. We show theoretically how the optimal benefit can depend significantly on borrowing constraints, and on other (non-precautionary) savings motives. We report empirical evidence that (i) a quarter of job losers cannot borrow for current consumption, (ii) this constraint is binding for a much smaller fraction, and (iii) that "excess sensitivity" is not limited to the constrained.unemployment, savings, credit constraints, life-cycle, consumption, unemployment insurance
Unexploited Connections Between Intra- and Inter-temporal Allocation
This paper shows that a power utility specification of preferences over total expenditure (ie. CRRA preferences) implies that intratemporal demands are in the PIGL/PIGLOG class. This class generates (at most) rank two demand systems and we can test the validity of power utility on cross-section data. Further, if we maintain the assumption of power utility, and within period preferences are not homothetic, then the intertemporal preference parameter is identified by the curvature of Engel curves. Under the power utility assumption, neither Euler equation estimation nor structural consumption function estimation is necessary to identify the power parameter. In our empirical work, we use demand data to estimate the power utility parameter and to test the assumption of the power utility representation. We find estimates of the power parameter larger than obtained from Euler equation estimation, but we reject the power specification of within period utility.elasticity of intertemporal substitution, Euler equation estimation, demand systems
Generating extremal neutrino mixing angles with Higgs family symmetries
The existence of maximal and minimal mixing angles in the neutrino mixing
matrix motivates the search for extensions to the Standard Model that may
explain these angles. A previous study (C.I.Low and R.R.Volkas,
Phys.Rev.D68,033007(2003)), began a systematic search to find the minimal
extension to the Standard Model that explains these mixing angles. It was found
that in the minimal extensions to the Standard Model which allow neutrino
oscillations, discrete unbroken lepton family symmetries only generate neutrino
mixing matrices that are ruled out by experiment. This paper continues the
search by investigating all models with two or more Higgs doublets, and an
Abelian family symmetry. It is found that discrete Abelian family symmetries
permit, but cannot explain, maximal atmospheric mixing, however these models
can ensure theta_{13}=0.Comment: Minor modifications, references added, typos corrected. LaTeX, 16
page
Job Loss, Credit Constraints and Consumption Growth
We use direct evidence on credit constraints to study their importance for household consumption growth and for welfare. We distentangle the direct effect on consumption growth of a currently binding credit constraints from the indirect effect of a potentially binding credit constraint which generates consumption risk. Our data is focused on job losers. We find that less than 5% of job losers experience a binding credit constraint, but for those that do, they experience significant welfare losses, and consumption growth is 24% higher than for the rest of the population. However, even among those who are currently unconstrained and who are able to borrow if needed, consumption responds to transitory income.Job Loss, Credit Constraints, Consumption
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