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Mensky has suggested to account for "continuous measurement" by attaching to a path integral a weight function centered around the classical path to which the integral assigns a probability amplitude. We show that in fact this weight function does not have to be viewed as an additional ingredient put in by hand. It can be derived instead from the conventional path integral if the infinitesimal term ie in the propagator is made finite; the "classical trajectory" is proportional to the current. [ABSTRACT FROM AUTHOR]

Accurately modeling an extreme-mass-ratio inspirai requires knowledge of the second-order gravita-tional self-force on the inspiraling small object. Recently, numerical puncture schemes have been formulated to calculate this force, and their essential analytical ingredients have been derived from first principles. However, the "puncture," a local representation of the small object's self-field, in each of these schemes has been presented only in a local coordinate system centered on the small object, while a numerical implementation will require the puncture in coordinates covering the entire numerical domain. In this paper we provide an explicit covariant self-field as a local expansion in terms of Synge's world function. The self-field is written in the Lorenz gauge, in an arbitrary vacuum background, and in forms suitable for both self-consistent and Gralla-Wald-type representations of the object's trajectory. We illustrate the local expansion's utility by sketching the procedure of constructing from it a numerically practical puncture in any chosen coordinate system. [ABSTRACT FROM AUTHOR]

We demonstrate experimentally the guiding of cold and slow ND3 molecules along a thin charged wire over a distance of ~0.34 m through an entire molecular beam apparatus. Trajectory simulations confirm that both linear and quadratic high-field-seeking Stark states can be efficiently guided from the beam source up to the detector. A density enhancement up to a factor 7 is reached for beams with velocities ranging down to ~ 150 m/s generated by the rotating nozzle technique. [ABSTRACT FROM AUTHOR]

An extreme mass ratio inspiral consists of two parts: adiabatic inspiral and plunge. The plunge trajectory from the innermost stable circular orbit is special (somewhat independent of initial conditions). We write an expression for its solution in closed form and for the emitted waveform. In particular we extract an expression for the associated black-hole ringdown amplitudes, and evaluate them numerically. [ABSTRACT FROM AUTHOR]

The gravitational couplings of matter are studied in the presence of Lorentz and CPT violation. At leading order in the coefficients for Lorentz violation, the relativistic quantum Hamiltonian is derived from the gravitationally coupled minimal standard-model extension. For spin-independent effects, the nonrelativistic quantum Hamiltonian and the classical dynamics for test and source bodies are obtained. A systematic perturbative method is developed to treat small metric and coefficient fluctuations about a Lorentz-violating and Minkowski background. The post-Newtonian metric and the trajectory of a test body freely falling under gravity in the presence of Lorentz violation are established. An illustrative example is presented for a bumblebee model. The general methodology is used to identify observable signals of Lorentz and CPT violation in a variety of gravitational experiments and observations, including gravimeter measurements, laboratory and satellite tests of the weak equivalence principle, antimatter studies, solar-system observations, and investigations of the gravitational properties of light. Numerous sensitivities to coefficients for Lorentz violation can be achieved in existing or near-future experiments at the level of parts in 103 down to parts in 1015. Certain coefficients are uniquely detectable in gravitational searches and remain unmeasured to date. [ABSTRACT FROM AUTHOR]

The predictive information required for proper trajectory sampling of a stochastic process can be more efficiently transmitted via a quantum channel than a classical one. This recent discovery allows quantum information processing to drastically reduce the memory necessary to simulate complex classical stochastic processes. It also points to a new perspective on the intrinsic complexity that nature must employ in generating the processes we observe. The quantum advantage increases with codeword length: the length of process sequences used in constructing the quantum communication scheme. In analogy with the classical complexity measure, statistical complexity, we use this reduced communication cost as an entropic measure of state complexity in the quantum representation. Previously difficult to compute, the quantum advantage is expressed here in closed form using spectral decomposition. This allows for efficient numerical computation of the quantum-reduced state complexity at all encoding lengths, including infinite. Additionally, it makes clear how finite-codeword reduction in state complexity is controlled by the classical process's cryptic order, and it allows asymptotic analysis of infinite-cryptic-order processes. [ABSTRACT FROM AUTHOR]