17 research outputs found
Astrophysical structures from primordial quantum black holes
The characteristic sizes of astrophysical structures, up to the whole
observed Universe, can be recovered, in principle, assuming that gravity is the
overall interaction assembling systems starting from microscopic scales, whose
order of magnitude is ruled by the Planck length and the related Compton
wavelength. This result agrees with the absence of screening mechanisms for the
gravitational interaction and could be connected to the presence of Yukawa
corrections in the Newtonian potential which introduce typical interaction
lengths. This result directly comes out from quantization of primordial black
holes and then characteristic interaction lengths directly emerge from quantum
field theory.Comment: 11 page
Sample-to-sample torque fluctuations in a system of coaxial randomly charged surfaces
Polarizable randomly charged dielectric objects have been recently shown to
exhibit long-range lateral and normal interaction forces even when they are
effectively net neutral. These forces stem from an interplay between the
quenched statistics of random charges and the induced dielectric image charges.
This type of interaction has recently been evoked to interpret measurements of
Casimir forces in vacuo, where a precise analysis of such disorder-induced
effects appears to be necessary. Here we consider the torque acting on a
randomly charged dielectric surface (or a sphere) mounted on a central axle
next to another randomly charged surface and show that although the resultant
mean torque is zero, its sample-to-sample fluctuation exhibits a long-range
behavior with the separation distance between the juxtaposed surfaces and that,
in particular, its root-mean-square value scales with the total area of the
surfaces. Therefore, the disorder-induced torque between two randomly charged
surfaces is expected to be much more pronounced than the disorder-induced
lateral force and may provide an effective way to determine possible disorder
effects in experiments, in a manner that is independent of the usual normal
force measurement.Comment: 7 pages, 3 fig
New possible detection schemes for relic Galactic neutrinos
We discuss the feasibility of the detection of relic neutrinos that may be present in the Galactic halo. We analyse their effect on macroscopic targets, comparing the detection proposals made so far and presenting new experimental schemes. In all cases the acceleration of the test masses is bounded by the value of the refractive index of neutrinos N as follows: a â 10-19(N - 1)x m s-2, where (N - 1) †10-8 for all materials and x = 0.5 in the best case. © 1996 IOP Publishing Ltd.Peer Reviewe
A beam balance method for determining the Newtonian constant of gravitation
Available from British Library Lending Division - LD:D52839/84 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
Searching for galactic axions through magnetized media: QUAX status report
The current status of the QUAX R\&D program is presented. QUAX is a feasibility study for a detection of axion as dark matter based on the coupling to the electrons. The relevant signal is a magnetization change of a magnetic material placed inside a resonant microwave cavity and polarized with a static magnetic field.The current status of the QUAX R&D program is presented. QUAX is a feasibility study for a detection of axion as dark matter based on the coupling to the electrons. The relevant signal is a magnetization change of a magnetic material placed inside a resonant microwave cavity and polarized with a static magnetic field