Physics
http://hdl.handle.net/2022/14235
2015-11-29T03:31:14ZAbsolute measurement of thermal noise in a resonant short-range force experiment
http://hdl.handle.net/2022/20512
Absolute measurement of thermal noise in a resonant short-range force experiment
Long, Josh
Planar, double-torsional oscillators are especially suitable for short-range
macroscopic force search experiments, since they can be operated at the limit
of instrumental thermal noise. As a study of this limit, we report a measurement
of the noise kinetic energy of a polycrystalline tungsten oscillator in
thermal equilibrium at room temperature. The fluctuations of the oscillator in a
high-Q torsional mode with a resonance frequency near 1 kHz are detected
with capacitive transducers coupled to a sensitive differential amplifier. The
electronic processing is calibrated by means of a known electrostatic force and
input from a finite-element model. The measured average kinetic energy,
Eexp = (2.0 ± 0.3) × 10E-21 J, is in agreement with the expected value of 1/2kBT.
Public domain version of publication, supporting data sets and analysis programs
2014-10-03T00:00:00ZBipartite Riemann–Finsler geometry and Lorentz violation
http://hdl.handle.net/2022/19672
Bipartite Riemann–Finsler geometry and Lorentz violation
Kostelecký, V.A.; Russell, N.; Tso, R.
Bipartite Riemann–Finsler geometries with complementary Finsler structures are constructed. Calculable examples are presented based on a bilinear-form coefficient for explicit Lorentz violation.
2012-01-01T00:00:00ZClassical kinematics for Lorentz violation
http://hdl.handle.net/2022/19671
Classical kinematics for Lorentz violation
Kostelecký, V.A.; Russell, N.
Classical point-particle relativistic lagrangians are constructed that generate the momentum–velocity and dispersion relations for quantum wave packets in Lorentz-violating effective field theory.
2010-01-01T00:00:00ZAstrophysical Tests of Lorentz and CPT Violation with Photons
http://hdl.handle.net/2022/19670
Astrophysical Tests of Lorentz and CPT Violation with Photons
Kostelecký, V.A.; Mewes, M.
A general framework for tests of Lorentz invariance with electromagnetic waves is presented, allowing for operators of arbitrary mass dimension. Signatures of Lorentz violations include vacuum birefringence, vacuum dispersion, and anisotropies. Sensitive searches for violations using sources such as active galaxies, gamma-ray bursts, and the cosmic microwave background are discussed. Direction-dependent dispersion constraints are obtained on operators of dimension 6 and 8 using gamma-ray bursts and the blazar Markarian 501. Stringent constraints on operators of dimension 3 are found using 5 year data from the Wilkinson Microwave Anisotropy Probe. No evidence appears for isotropic Lorentz violation, while some support at 1 σ is found for anisotropic violation.
2008-01-01T00:00:00Z