66,996 research outputs found
Four-path interference and uncertainty principle in photodetachment microscopy
We study the quantal motion of electrons emitted by a pointlike monochromatic
isotropic source into parallel uniform electric and magnetic fields. The
two-path interference pattern in the emerging electron wave due to the electric
force is modified by the magnetic lens effect which periodically focuses the
beam into narrow filaments along the symmetry axis. There, four classical paths
interfere. With increasing electron energy, the current distribution changes
from a quantum regime governed by the uncertainty principle, to an intricate
spatial pattern that yields to a semiclassical analysis.Comment: submitted to Europhysics Letter
A hole-ographic spacetime
We embed spherical Rindler space -- a geometry with a spherical hole in its
center -- in asymptotically AdS spacetime and show that it carries a
gravitational entropy proportional to the area of the hole. Spherical
AdS-Rindler space is holographically dual to an ultraviolet sector of the
boundary field theory given by restriction to a strip of finite duration in
time. Because measurements have finite durations, local observers in the field
theory can only access information about bounded spatial regions. We propose a
notion of Residual Entropy that captures uncertainty about the state of a
system left by the collection of local, finite-time observables. For
two-dimensional conformal field theories we use holography and the strong
subadditivity of entanglement to propose a formula for Residual Entropy and
show that it precisely reproduces the areas of circular holes in AdS3.
Extending the notion to field theories on strips with variable durations in
time, we show more generally that Residual Entropy computes the areas of all
closed, inhomogenous curves on a spatial slice of AdS3. We discuss the
extension to higher dimensional field theories, the relation of Residual
Entropy to entanglement between scales, and some implications for the emergence
of space from the RG flow of entangled field theories.Comment: v3: minor typos correcte
Study of the neutron quantum states in the gravity field
We have studied neutron quantum states in the potential well formed by the
earth's gravitational field and a horizontal mirror. The estimated
characteristic sizes of the neutron wave functions in the two lowest quantum
states correspond to expectations with an experimental accuracy. A
position-sensitive neutron detector with an extra-high spatial resolution of ~2
microns was developed and tested for this particular experiment, to be used to
measure the spatial density distribution in a standing neutron wave above a
mirror for a set of some of the lowest quantum states. The present experiment
can be used to set an upper limit for an additional short-range fundamental
force. We studied methodological uncertainties as well as the feasibility of
improving further the accuracy of this experiment
- …